The Miniliths: A project based on the Seas CA21REX, Neo8 PDR & Neo3 PDR

Collapse
This topic is closed.
X
X
 
  • Time
  • Show
Clear All
new posts
  • fjhuerta
    Super Senior Member
    • Jun 2006
    • 1140

    The Miniliths: A project based on the Seas CA21REX, Neo8 PDR & Neo3 PDR

    So, I had a couple of weeks to start some work on my Neo-based project. Since I already have a pair of Monoliths (my last project), and I'm considering building the Megaliths (an MTMWW tower), I thought the Miniliths name would fit within the "series".

    Anyway, as always, here are my objectives for this project.

    1) An accurate 3 way monitor speaker.
    2) As small as possible.
    3) Mostly for nearfield listening (as huge PC speakers), or semi-full range speakers (need a sub to sound their best).
    4) Able to be biamped (my main idea is to use two T-Amps with a bit regulated power supply).
    5) Accurate - as flat as possible (a huge issue, considering the FR of the Neo3).
    6) Monopolar.
    7) High WAF.

    I have the following issues.

    1) FR of the Neo3 & Neo8.
    2) Crossover slopes and cut-off points.
    3) Diffraction issues.
    4) Mounting the Neo3 and 8.
    5) Size of the cabinet.

    More to come...
    Javier Huerta
  • fjhuerta
    Super Senior Member
    • Jun 2006
    • 1140

    #2
    Baffle layout and size

    I decided to go sealed. Considering that my available 8" woofers (in case I didn't like something about the Seas) could work well with about 12 liters (the Dayton 225, and the Audax AP210ZO), that's what I used.

    Here's the layout and size.

    Click image for larger version

Name:	baffle.png
Views:	15154
Size:	53.5 KB
ID:	849162

    1" MDF all around, veneered. Nothing fancy, just something practical and nice.

    According to Edge, diffraction shouldn't be an issue with drivers this big. We'll see.

    Click image for larger version

Name:	21072007048.jpg
Views:	15408
Size:	46.2 KB
ID:	849164

    Click image for larger version

Name:	22072007053.jpg
Views:	20261
Size:	74.3 KB
ID:	849165

    Click image for larger version

Name:	front.jpg
Views:	15639
Size:	37.9 KB
ID:	849166
    Last edited by theSven; 07 May 2023, 09:18 Sunday. Reason: Update image location
    Javier Huerta

    Comment

    • JonMarsh
      Mad Max Moderator
      • Aug 2000
      • 15254

      #3
      Aren't there always issues? :W

      Sounds like an interesting project, Javier- anything special in mind for the size and shape of the cabinet?

      I'll be interested to see how this turns out for you.

      A lot of three ways popping up lately... :B
      the AudioWorx
      Natalie P
      M8ta
      Modula Neo DCC
      Modula MT XE
      Modula Xtreme
      Isiris
      Wavecor Ardent

      SMJ
      Minerva Monitor
      Calliope
      Ardent D

      In Development...
      Isiris Mk II updates- in final test stage!
      Obi-Wan
      Saint-Saëns Symphonique/AKA SMJ-40
      Modula PWB
      Calliope CC Supreme
      Natalie P Ultra
      Natalie P Supreme
      Janus BP1 Sub


      Resistance is not futile, it is Volts divided by Amperes...
      Just ask Mr. Ohm....

      Comment

      • fjhuerta
        Super Senior Member
        • Jun 2006
        • 1140

        #4
        Originally posted by JonMarsh
        Aren't there always issues? :W

        Sounds like an interesting project, Javier- anything special in mind for the size and shape of the cabinet?

        I'll be interested to see how this turns out for you.

        A lot of three ways popping up lately... :B
        Hi Jon!

        Yep, I tried to immitate a MartinLogan in a smaller size (yeah, things don't always work that way, as you'll soon see!).

        And a lot of issues came up. Good thing is, I'm in no rush to finish this speaker.
        Javier Huerta

        Comment

        • fjhuerta
          Super Senior Member
          • Jun 2006
          • 1140

          #5
          Bass response and cabinet

          Here's the plot of FR for the cabinet. Nice, not to deep a response, but OK. Measured with the Woofer Tester 2, I got a nice 0.64 Qts.

          Click image for larger version

Name:	Seas CA21REX.gif
Views:	15007
Size:	24.1 KB
ID:	849163

          Here are the finished baffles, with wiring included.





          Last edited by theSven; 07 May 2023, 09:19 Sunday. Reason: Update image location
          Javier Huerta

          Comment

          • fjhuerta
            Super Senior Member
            • Jun 2006
            • 1140

            #6
            This is where the fun stops

            According to my estimates, the speaker would be an 89 dB/W model...

            But something's definitely wrong here. Either I got a pair of macho woofers, or...

            Here's the woofer's FR plot, according to SEAS.

            Click image for larger version

Name:	SeasFR.gif
Views:	14913
Size:	62.6 KB
ID:	849167

            Almost 90 dB, considering baffle step. Not bad!

            The Neo3 and Neo8 graphs have their lowest point at 90 dB, so I assumed I wouldn't have any problems here. Well, not really.

            Here's the FR of my first iteration of the crossover.

            Click image for larger version

Name:	Nueva imagen.gif
Views:	15343
Size:	49.0 KB
ID:	849168

            Hey, not bad, considering it's the Neo3 and Neo8 PDR...

            Here's the impedance plot:

            Click image for larger version

Name:	Nueva imagen (2).gif
Views:	14738
Size:	47.4 KB
ID:	849170

            A little bit too low for my taste, but still not bad... hey, there's something wrong with the bass unit. See if you can guess what the problem is...

            Well, here is the problem:

            Click image for larger version

Name:	Nueva imagen (1).gif
Views:	15411
Size:	39.0 KB
ID:	849169

            See that resistor on the woofer leg of the circuit?

            Yep. The woofer is more efficient than the mids or tweeters. By a whopping 3 dB.

            This can't be happening.

            Right now, the only thing I can think of is that I overstuffed the tweeter and midrange cavities. I used a lot (A LOT) of dacron. Basically, the Neos chassis are pushing against it.

            I surely hope this is the problem. I need to correct it and take measurements again.

            Here's the response without the padding resistor.

            Click image for larger version

Name:	UnmoddedFR.gif
Views:	14652
Size:	49.0 KB
ID:	849171

            And my problem turns out to be a bit more tricky. Even if I the tweeter and mids respond well to taking out some dacron... the impedance on the woofer drops below 2 Ohm when trying to use a 4th order electrical filter.

            Wow.

            What do you think about this problem? I think I need to do a couple of things.

            1) Re-measure the speaker without so much dacron.
            2) Re-design the woofer / mid portion, shoot for a 2nd order filter at 800 Hz.

            If this doesn't help, I'll switch drivers and go for the Dayton RS woofer... with an 8 Ohm impedance and lower sensitivity it may help.
            Last edited by theSven; 07 May 2023, 11:33 Sunday. Reason: Update image location
            Javier Huerta

            Comment

            • cjd
              Ultra Senior Member
              • Dec 2004
              • 5568

              #7
              Have you verified the voltage at the speaker terminals?

              Also, at what distance are you measuring?

              Do you know what the baffle conditions were for the b&w measurement you've provided are? If it's effectively dipole....

              C
              diVine Sound - my DIY speaker designs at diVine Audio

              Comment

              • Dennis H
                Ultra Senior Member
                • Aug 2002
                • 3791

                #8
                Is the planar baffle sealed on the back? If so, I think B&G recommends at least at least 5" of depth and light stuffing for the big RD planars which cover a similar freq range as the Neo8.

                Comment

                • Jed
                  Ultra Senior Member
                  • Apr 2005
                  • 3617

                  #9
                  How are you handling BSC?

                  Comment

                  • fjhuerta
                    Super Senior Member
                    • Jun 2006
                    • 1140

                    #10
                    Hi C,

                    I did verify the voltage... well, I think that's what JustMLS does when in 2-channel measurement mode. It has never failed me before.

                    I measured at 1.2 meters. That distance seemed to help regarding the FR of the planar drivers.

                    The baffle conditions are: 10L box, anechoic. I don't think the baffle dimensions are shown on the graph (I got it from the SEAS web site).

                    Dennis, the baffle is sealed, indeed, but it has only a 1" depth. Yikes. I surely hope the Neo8 doesn't require a 5" depth - if not, I'm in serious trouble!!!

                    Thanks a lot for your help.
                    Javier Huerta

                    Comment

                    • Jed
                      Ultra Senior Member
                      • Apr 2005
                      • 3617

                      #11
                      Did you splice the nearfield data of the woofer with farfield and forget to add in BSC? The woofer data may be incorrect.

                      Comment

                      • fjhuerta
                        Super Senior Member
                        • Jun 2006
                        • 1140

                        #12
                        Originally posted by Jed
                        How are you handling BSC?
                        Via the woofer circuit. As far as I can tell, there's no BSC on the midrange (I'm crossing over at 700 Hz).

                        I calculated the correct woofer response by doing the usual things... nearfield, farfield, KHF tool...
                        Javier Huerta

                        Comment

                        • fjhuerta
                          Super Senior Member
                          • Jun 2006
                          • 1140

                          #13
                          Originally posted by Jed
                          Did you splice the nearfield data of the woofer with farfield and forget to add in BSC? The woofer data may be incorrect.
                          Heh, that was exactly the first thing I thought of! Still, I just re-checked (just in case) and I'm using the corrected woofer response.
                          Javier Huerta

                          Comment

                          • fjhuerta
                            Super Senior Member
                            • Jun 2006
                            • 1140

                            #14
                            2nd x-over revision

                            Since I won't be able to re-measure the speaker until later this week, I spent some time playing with the x-over layout.

                            I changed the woofer's 4th order electrical to a 2nd order electrical, and tried to hit a 4th order acoustical slope. The result was great from an impedance standpoint. Then I shaped the response so as to create a downward slope (a bit of warmth).

                            In case the measurements are correct, I'll be using this crossover as a starting point for the definitive version.

                            According to my measurements, off-axis response will be pretty good, although it's only a simulation. I'll take 30° and 60° measurements this weekend, to be on the safe side.

                            So far, pairing the Neo3 and the Neo8 has been most helpful. The Neo8 is far easier to work with. Also, removing the Neo3's small baffle and using a sealed box extended its FR by at least 600 Hz!

                            FR

                            Click image for larger version

Name:	Miniliths21.gif
Views:	14580
Size:	45.9 KB
ID:	849176

                            Impedance

                            Click image for larger version

Name:	Miniliths22.gif
Views:	14274
Size:	40.8 KB
ID:	849177

                            New circuit

                            Click image for larger version

Name:	Miniliths23.gif
Views:	14291
Size:	40.5 KB
ID:	849178
                            Last edited by theSven; 07 May 2023, 11:34 Sunday. Reason: Update image location
                            Javier Huerta

                            Comment

                            • cjd
                              Ultra Senior Member
                              • Dec 2004
                              • 5568

                              #15
                              I bet you could get away with softer slopes mid-tweeter. 2nd order acoustic perhaps. Might help with various things and will obviously simplify the circuit.

                              C
                              diVine Sound - my DIY speaker designs at diVine Audio

                              Comment

                              • fjhuerta
                                Super Senior Member
                                • Jun 2006
                                • 1140

                                #16
                                Originally posted by cjd
                                I bet you could get away with softer slopes mid-tweeter. 2nd order acoustic perhaps. Might help with various things and will obviously simplify the circuit.

                                C
                                Thanks a lot for your input (again!) C. The reason I rolled the Neo3 so fast was because I've had bad experience trying to work around its FR, and when I saw the Neo8 was actually flatter, I decided to mainly use the 3 almost as a supertweeter.

                                One thing I've noticed is that after removing its back enclosure and giving it some room to breathe, its FR measured a bit better.

                                I'll try 2nd order, just like you said. I tried doing the same between woofer and Neo8, and the results weren't that great... at 700 Hz, actually, the 8's roll-off was basically 2nd order acoustic!
                                Javier Huerta

                                Comment

                                • cjd
                                  Ultra Senior Member
                                  • Dec 2004
                                  • 5568

                                  #17
                                  Yeah, I'd still keep the target frequency where it is - you'll still get primary contribution from the Neo8, but you may pick up response levels a bit more and even out some of the peakiness that exists in the top octave.

                                  C
                                  diVine Sound - my DIY speaker designs at diVine Audio

                                  Comment

                                  • fjhuerta
                                    Super Senior Member
                                    • Jun 2006
                                    • 1140

                                    #18
                                    Forgot to add - I usede Meniscus' Audio metal plates for mounting. I can't recommend them enough - they look as if they were an integral part of the Neo's. Awesome product at a great price.

                                    Anyway, I've been playing with 2nd order slopes. I have an issue... the drivers' aren't in phase, so I have even worse of a frequency response.

                                    I'm thinking about emulating the crossover and listening to it with both crossovers. The 2nd order ones are a lot simpler.

                                    I also need those off-axis FR plots...
                                    Javier Huerta

                                    Comment

                                    • Landroval
                                      Senior Member
                                      • Dec 2005
                                      • 175

                                      #19
                                      Interesting project Javier. I guess all the bad stories about B&G Neo drivers tell only that they need a bit of trial&error to get good performance out.. many people don't bother to try enough.

                                      I came across this:


                                      Looks like Neo8 with quite a low price. Do you guys have any idea what's the story behind that one?

                                      Comment

                                      • cjd
                                        Ultra Senior Member
                                        • Dec 2004
                                        • 5568

                                        #20
                                        Originally posted by fjhuerta
                                        Anyway, I've been playing with 2nd order slopes. I have an issue... the drivers' aren't in phase, so I have even worse of a frequency response.
                                        Keep fiddling. Perhaps the target frequency has to shift a little. Or try switching to a series hybrid. I often find that I have to fiddle quite a bit before things really gel, but when they do it's SO nice. How far off is phase? Maybe a 3rd order slope would be a better fit. Or an asymmetrical mix, 4th on the Neo8, 2nd on the Neo3. Or...

                                        This is the fun part, you know?!

                                        C
                                        diVine Sound - my DIY speaker designs at diVine Audio

                                        Comment

                                        • fjhuerta
                                          Super Senior Member
                                          • Jun 2006
                                          • 1140

                                          #21
                                          OK, I finally re-measured the speakers and took off-axis measurements. I then compared the measurements to the original ones, and used the off-axis measurements to find out which version of the crossover looks better (2nd order vs. 4th order).

                                          1) The original measurements are correct. The Seas woofer seems to have a higher sensitivity than the Neo drivers. I measured voltages, measured every curve, etc. Removing the stuffing from the drivers seemed to make their responses a bit more ragged - sensitivity was unchanged.

                                          2) Off-axis, the 2nd order filter has some major suck-outs on the mid-tweeter crossover region at 30°. While, at 0°, both drivers sum perfectly well, at 30° they look to be out of phase.

                                          3) Off axis, the 3rd order filter has a flare at 5 KHz. I had to shape the response curve to mitigate it as much as possible without affecting FR on-axis.

                                          So, for now, 4th order acoustical seems to be the best bet. I'll still keep on playing with 2nd order... or different topologies.

                                          I'll post some graphs later today, or tomorrow.
                                          Javier Huerta

                                          Comment

                                          • fjhuerta
                                            Super Senior Member
                                            • Jun 2006
                                            • 1140

                                            #22
                                            AAAaaargghhhh

                                            I should have suspected it. There's a reason there aren't many 3-ways being designed in this forum.

                                            3-ways are hard!

                                            Especially when the drivers are physically big, and they don't have nice horizontal dispersion.

                                            At this point, I'm seriously considering just unplugging the Neo3 PDR.

                                            The issue?

                                            Off-axis response! Due to their horizontal placement and (I assume) the distance between drivers, off axis response is terrible!

                                            Depending on the listening axis, response develops major suck-outs - when I use a 2nd order x-over, the only difference is that they appear at different angles.

                                            I seriously don't think this issue can be solved, unless I raise the x-over frequency and make the Neo3 irrelevant. But I'd like to avoid the peak in FR from the Neo8.

                                            Any ideas?



                                            (The only FR with nearfield / farfield is at 0°).

                                            Click image for larger version

Name:	FR.gif
Views:	14001
Size:	59.9 KB
ID:	849195

                                            (My next speaker WILL be a 2 way).
                                            Last edited by theSven; 07 May 2023, 11:35 Sunday. Reason: Update image location
                                            Javier Huerta

                                            Comment

                                            • Jed
                                              Ultra Senior Member
                                              • Apr 2005
                                              • 3617

                                              #23
                                              looks like the tweeter phase should be reversed, with that null off axis, so maybe instead of doing that, you could shoot for a lower crossover point to avoid the cancellations you are getting in the higher frequencies.

                                              Comment

                                              • fjhuerta
                                                Super Senior Member
                                                • Jun 2006
                                                • 1140

                                                #24
                                                So far, no luck.

                                                I spent all night playing with X-over points. From 4KHz to 12 KHz, and every time I get a null at 15° off-axis.

                                                At this point, I can't help but realize this design is flawed from the start.

                                                The reason why I placed the drivers side by side instead of top-down was because I saw a MartinLogan which used this baffle layout. I suspected they did this because of the limited vertical dispersion of the Neo8, and thought it was a good idea.

                                                Now I realize that a better idea would have been to do a T-M-W and design using the M as the listening axis, letting the Neo3 fill in the upper octave with its wider vertical dispersion.

                                                I'm still wondering whether to build this speaker, or re-design with a new cabinet.
                                                Javier Huerta

                                                Comment

                                                • Jed
                                                  Ultra Senior Member
                                                  • Apr 2005
                                                  • 3617

                                                  #25
                                                  Originally posted by fjhuerta
                                                  So far, no luck.

                                                  I spent all night playing with X-over points. From 4KHz to 12 KHz, and every time I get a null at 15° off-axis.

                                                  At this point, I can't help but realize this design is flawed from the start.

                                                  The reason why I placed the drivers side by side instead of top-down was because I saw a MartinLogan which used this baffle layout. I suspected they did this because of the limited vertical dispersion of the Neo8, and thought it was a good idea.

                                                  Now I realize that a better idea would have been to do a T-M-W and design using the M as the listening axis, letting the Neo3 fill in the upper octave with its wider vertical dispersion.

                                                  I'm still wondering whether to build this speaker, or re-design with a new cabinet.
                                                  If you are using 4th order acoustic slopes in a 3-way for HP, LP, and bandpass, all drivers should be in positive polarity. It appears that you have the tweeter reversed, and although on axis is flat, it is not where it should be for a technically correct system.

                                                  So, reverse that tweeter polarity like I suggested earlier, before you scrap this project because I think that is the problem.

                                                  Comment

                                                  • fjhuerta
                                                    Super Senior Member
                                                    • Jun 2006
                                                    • 1140

                                                    #26
                                                    Hi Jed,

                                                    The graphs I posted were for the system with everything with positive polarity. I made an error in my original measurements - the tweeter polarity was reversed.

                                                    I just modeled the speaker in a TMW arrangement, and I see there's no tweeter cancellation if designed with the listener axis on the Neo8. When I model it as I have it right now, I can see that the cancellation is there (memo to myself: model before building!).

                                                    As it is, right now I'm wondering whether I should build the speaker correctly, or just live with the FR for a while.
                                                    Javier Huerta

                                                    Comment

                                                    • Jed
                                                      Ultra Senior Member
                                                      • Apr 2005
                                                      • 3617

                                                      #27
                                                      Originally posted by fjhuerta
                                                      Hi Jed,

                                                      The graphs I posted were for the system with everything with positive polarity. I made an error in my original measurements - the tweeter polarity was reversed.
                                                      I see, that tweeter phase still looks wrong to me. Are your slopes true 4th order, or more like asymmetrical?

                                                      Comment

                                                      • fjhuerta
                                                        Super Senior Member
                                                        • Jun 2006
                                                        • 1140

                                                        #28
                                                        True 4th order.
                                                        Javier Huerta

                                                        Comment

                                                        • Jed
                                                          Ultra Senior Member
                                                          • Apr 2005
                                                          • 3617

                                                          #29
                                                          Would you mind posting a screenshot of the system when the tweeter is in negative polarity?

                                                          Another option might be a steeper slope between mid and tweeter.

                                                          Comment

                                                          • fjhuerta
                                                            Super Senior Member
                                                            • Jun 2006
                                                            • 1140

                                                            #30
                                                            Originally posted by Jed
                                                            Would you mind posting a screenshot of the system when the tweeter is in negative polarity?

                                                            Another option might be a steeper slope between mid and tweeter.
                                                            Sure thing. Great idea on the steeper slopes - I tried slower ones.

                                                            Image not available

                                                            Image not available
                                                            Last edited by theSven; 07 May 2023, 11:37 Sunday. Reason: Update image location
                                                            Javier Huerta

                                                            Comment

                                                            • Jed
                                                              Ultra Senior Member
                                                              • Apr 2005
                                                              • 3617

                                                              #31
                                                              Thanks, but I can't see your pics, broken links.

                                                              Comment

                                                              • fjhuerta
                                                                Super Senior Member
                                                                • Jun 2006
                                                                • 1140

                                                                #32
                                                                Click image for larger version

Name:	FreqResp.gif
Views:	13918
Size:	39.5 KB
ID:	849198

                                                                Click image for larger version

Name:	FreqResp2.gif
Views:	13711
Size:	45.5 KB
ID:	849199

                                                                Here they are. That's strange - I was certain I had uploaded them before.
                                                                Last edited by theSven; 07 May 2023, 11:37 Sunday. Reason: Update image location
                                                                Javier Huerta

                                                                Comment

                                                                • Jed
                                                                  Ultra Senior Member
                                                                  • Apr 2005
                                                                  • 3617

                                                                  #33
                                                                  Originally posted by fjhuerta

                                                                  Here they are. That's strange - I was certain I had uploaded them before.
                                                                  Lookin better and how is the off axis now?

                                                                  Comment

                                                                  • fjhuerta
                                                                    Super Senior Member
                                                                    • Jun 2006
                                                                    • 1140

                                                                    #34
                                                                    Originally posted by Jed
                                                                    Lookin better and how is the off axis now?
                                                                    It isn't still how I'd like it to be, Jed.

                                                                    Still, I've noticed something. I quickly built a higher order crossover, and the cancellaton isn't anywhere as severe as a 4th order (I went for a 6th order), the FR is flatter... and I found out that when tweeters are placed on the outside, cancellation doesn't occur at all. Tweeters on the inside are problematic.

                                                                    This could be the solution to this problem. As long as the listener is in the sweet spot, the speakers will sound good. Since I already knew vertical dispersion would be poor, the "sweet spot" listening won't be an issue.
                                                                    Javier Huerta

                                                                    Comment

                                                                    • Jed
                                                                      Ultra Senior Member
                                                                      • Apr 2005
                                                                      • 3617

                                                                      #35
                                                                      Sounds like you are getting to the bottom of it. :T

                                                                      Comment

                                                                      • fjhuerta
                                                                        Super Senior Member
                                                                        • Jun 2006
                                                                        • 1140

                                                                        #36
                                                                        Jed, you are probably right, and I have to thank you for it. Quite frankly, if you hadn't guided me through it, I'd have probably forgotten about this cabinet.

                                                                        Anyway, a 6th order filter seemed to help a lot. I'll probably be refining the crossover point a bit during the week, but I don't expect the topology to change that much.

                                                                        I have very minor cancellation now, considering the size of the drivers, I guess this was pretty much unavoidable.

                                                                        Anyway, I may try to drop a bit the x-over frequency on the tweeter, but nothing too serious (500 Hz or less, perhaps).

                                                                        Click image for larger version

Name:	6th1.gif
Views:	11572
Size:	43.8 KB
ID:	849200

                                                                        Click image for larger version

Name:	6th2.gif
Views:	10730
Size:	47.7 KB
ID:	849201

                                                                        (FR as measured with the tweeters on the outside).
                                                                        Last edited by theSven; 07 May 2023, 11:52 Sunday. Reason: Update image location
                                                                        Javier Huerta

                                                                        Comment

                                                                        • Jed
                                                                          Ultra Senior Member
                                                                          • Apr 2005
                                                                          • 3617

                                                                          #37
                                                                          :T Glad I could help out. I'm sure they'll sound as good as they look. I haven't tried those BG mids/tweets yet myself, so let us know your impressions.

                                                                          Comment

                                                                          • fjhuerta
                                                                            Super Senior Member
                                                                            • Jun 2006
                                                                            • 1140

                                                                            #38
                                                                            I forgot to check one thing... impedance.

                                                                            It drops below 2 Ohm.

                                                                            I'm designing a new cabinet with side-firing woofers. I simulated in LSPCad the required distances to avoid phase cancellation. And yes, the tweeter is now on top of the mid.

                                                                            I'll build it in el-cheapo MDF, just in case I sc**w something up again.

                                                                            (Hey, if I'm using relatively expensive / nice drivers, there's no use in paying good $ for a crossover when I'm not sure of the results! - plus, the new cabinets may look very cool).

                                                                            I'll post again when I sort these issues out.
                                                                            Javier Huerta

                                                                            Comment

                                                                            • Jed
                                                                              Ultra Senior Member
                                                                              • Apr 2005
                                                                              • 3617

                                                                              #39
                                                                              Originally posted by fjhuerta
                                                                              I forgot to check one thing... impedance.

                                                                              It drops below 2 Ohm.


                                                                              I'll post again when I sort these issues out.
                                                                              Ouch, oh well you tried to salvage those boxes. Live and learn as they say.

                                                                              Comment

                                                                              • cjd
                                                                                Ultra Senior Member
                                                                                • Dec 2004
                                                                                • 5568

                                                                                #40
                                                                                They always say, you learn more from your mistakes... I may have been unsure about whether a side-by-side alignment would work before - now we all KNOW the answer far more specifically. :P

                                                                                You can leave a little more volume in there for the mid this time too.

                                                                                Having fun still I hope!

                                                                                C
                                                                                diVine Sound - my DIY speaker designs at diVine Audio

                                                                                Comment

                                                                                • fjhuerta
                                                                                  Super Senior Member
                                                                                  • Jun 2006
                                                                                  • 1140

                                                                                  #41
                                                                                  C, it's always about having fun

                                                                                  I designed two new cabinets. This time, I'll have them built out of raw MDF, and choose between them. One of them is a standard 3 way tower, T-M-W. It's quite probable the listening axis will be on the center of the Neo8, but we'll see. I'm sure this one will work, since I already modeled it extensively.

                                                                                  The second one is a rather unusual design. It has the Neo8 and 3 mounted in the front baffle, and the 8" woofer firing sideways. According to LSPCad, at 200 mm from the front baffle, and with inverse polarity, the woofer sums up with the Neo8. Since LSPCad isn't taking into consideration the size and shape of the actual box, I'm not sure this box will work. I hope it does, since I think it'd look very cool.

                                                                                  Any thoughts about it? The boxes themselves were not that expensive, so I'll have them by next week.

                                                                                  Click image for larger version

Name:	baffle2gif.gif
Views:	215
Size:	84.9 KB
ID:	936326
                                                                                  Last edited by theSven; 07 May 2023, 11:54 Sunday. Reason: Update image location
                                                                                  Javier Huerta

                                                                                  Comment

                                                                                  • fjhuerta
                                                                                    Super Senior Member
                                                                                    • Jun 2006
                                                                                    • 1140

                                                                                    #42
                                                                                    Some real progress.

                                                                                    After finally deciding the baffles were all wrong (and the woofer enclosure could be a bit bigger), I built two new enclosures.

                                                                                    One of them had a side-firing woofer, the other is a normal TMW baffle.

                                                                                    Anyway, the one with the side-firing woofer was GREAT... on axis. Off axis (obviously enough now, not so obvious back then), FR depended on whether you were listening directly to the woofer or not. Since the x-over point was around 700 Hz, the speaker was unusable.

                                                                                    The TMW baffle showed some promise, so I decided to work on it... and after a couple of weeks, this is what I ended with. Other tha vertical off-axis response (which I already knew wouldn't be that great, due to the tallish drivers), I think the design turned out quite fine.

                                                                                    One of the things I love about it is that it uses no resistors whatsoever. Levels were adjusted using the inductors' resistance (and, quite honestly, they aren't that critical - but the values I have for them are the most exact ones).

                                                                                    I don't have any pictures of the baffles, since they are being finished right now, but here's the final circuit and lots of graphs.

                                                                                    Another thing - these drivers' response off axis is... ahem, well, not really flat. Things start looking much better at 15°. I can't imagine designing a speaker using these drivers without considering off-axis response as well as on-axis.

                                                                                    (Note: Off-axis response is not an LSPCad simulation - it's taken from real 15° and 30° off-axis measurements. This is the only way to see how critical off-axis response seems to be with these drivers).

                                                                                    Schema:

                                                                                    Click image for larger version

Name:	Schema.gif
Views:	10255
Size:	37.7 KB
ID:	849304

                                                                                    On axis:

                                                                                    Click image for larger version

Name:	OnAxis.gif
Views:	10061
Size:	68.0 KB
ID:	849305

                                                                                    15° off axis:

                                                                                    Click image for larger version

Name:	15deg.gif
Views:	10042
Size:	69.3 KB
ID:	849307

                                                                                    30° off axis:

                                                                                    Click image for larger version

Name:	30deg.gif
Views:	10154
Size:	69.1 KB
ID:	849308

                                                                                    Power response:

                                                                                    Click image for larger version

Name:	PowerResponse.gif
Views:	10577
Size:	70.0 KB
ID:	849306
                                                                                    Last edited by theSven; 07 May 2023, 11:55 Sunday. Reason: Update image location
                                                                                    Javier Huerta

                                                                                    Comment

                                                                                    • fjhuerta
                                                                                      Super Senior Member
                                                                                      • Jun 2006
                                                                                      • 1140

                                                                                      #43
                                                                                      Transfer function:

                                                                                      Click image for larger version

Name:	transferfunction.gif
Views:	9928
Size:	62.0 KB
ID:	849309

                                                                                      Impedance:

                                                                                      Click image for larger version

Name:	imp.gif
Views:	10161
Size:	63.3 KB
ID:	849310
                                                                                      Last edited by theSven; 07 May 2023, 11:55 Sunday. Reason: Update image location
                                                                                      Javier Huerta

                                                                                      Comment

                                                                                      • Landroval
                                                                                        Senior Member
                                                                                        • Dec 2005
                                                                                        • 175

                                                                                        #44
                                                                                        I really appreciate how you get an idea and then try it out no matter how unusual it is. That's the way to get new cool inventions. As someone wise said, most breakthroughs in science didn't come after "Heureka, I did it" but "hmmh, that's interesting".

                                                                                        The sidefiring could work if:
                                                                                        1) It had lower xo point and/or
                                                                                        2) smaller woofers and/or
                                                                                        3) woofers firing to both sides

                                                                                        Here's some examples where sidefiring woofers are used:

                                                                                        Extreme High-End Audio products  Simply the Best Loudspeakers in the World!


                                                                                        Comment

                                                                                        • fjhuerta
                                                                                          Super Senior Member
                                                                                          • Jun 2006
                                                                                          • 1140

                                                                                          #45
                                                                                          Success!

                                                                                          After what seemed like months of hard work (oh, wait - it really took that long), I finally finished my speakers

                                                                                          I'm absolutely blown away at the Neo drivers in this configuration. By combining the 8 and 3 , I avoided most of the issues (especially regarding FR) I had with the Neo3 alone.

                                                                                          The Neo8, crossed at 800Hz, is simply superb.

                                                                                          How good is it?

                                                                                          Here's an idea - I was listening to the "Brothers in Arms" XRCD2 disc today, and I was sure I had blown a speaker. It had a very strange distortion I had never heard. After swapping channels, speakers, amplifiers, versions of the album, and listening to both speakers side by side I realized something - the distortion I was listening to came from the bass guitar itself. It was so real and pure, I thought the Neo8 had blown up! :E

                                                                                          Now I have a question... can a dynamic driver sound as realistic as the planar ones? I've listened to many, but I had never confused real life distortion with recorded distortion. And I don't think I've ever heard a speaker with such dynamic transients, either (except for my old MartinLogan Scenarios, which were quite quick with transients, but sounded terrible).

                                                                                          I'm sold on these drivers. I'll try to post some pictures and more information tomorrow.
                                                                                          Javier Huerta

                                                                                          Comment

                                                                                          Working...
                                                                                          😀
                                                                                          😂
                                                                                          🥰
                                                                                          😘
                                                                                          🤢
                                                                                          😎
                                                                                          😞
                                                                                          😡
                                                                                          👍
                                                                                          👎
                                                                                          Searching...Please wait.
                                                                                          An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

                                                                                          Please push the back button and reload the previous window.'
                                                                                          An unexpected error was returned: 'Your submission could not be processed because the token has expired.

                                                                                          Please push the back button and reload the previous window.'
                                                                                          An internal error has occurred and the module cannot be displayed.
                                                                                          There are no results that meet this criteria.
                                                                                          Search Result for "|||"