Speaker-Camp, R&D for Modula NeoD CC speaker variants

[Hdale85]

Hey Jon, Would these work out good in a floor standing enclosure for the fronts? Especially something like the RS180 version I would think would benefit from something like this? Was just thinking how much lower do you think it would run in a floorstanding enclosure.

[Brian Bunge]

I would think that you could go with the same volume and tuning as with the NatP/Modula MTM tower cabinet design if you were so inclined.

[Gir]

Whoa, I have that exact same workbench.

Me too!! :E :E :E

[TacoD]

Conclusion:
You need a B&D workmate if you want to make proper loudspeakers .

p.s. I've a smaller one.

[JonMarsh]

As Brian notes in his post, the same LF tuning principles apply as for the MTM's using these woofers... no doubt the larger cabinet would be of benefit for those wanting to build from scratch and preferring a tower configuration. In the final build thread we'll post Unibox analysis for the suggested midwoofers documenting that. I'm not personally planning on building and testing larger versions- (there's where the Y in DIY comes in), as I have other fish to fry... such as finishing assembling the next test article on the Arvo Isiris.

[JonMarsh]

Conclusion:
You need a B&D workmate if you want to make proper loudspeakers .

p.s. I've a smaller one.

It's a very handy piece of kit for not much money- the current version of the 400, the 425, sells for about $75 at Amazon, $90 at Target online.

[chasw98]

such as finishing assembling the next test article on the Arvo Isiris.

I am looking forward to that!







P. P. S. And hopefully a glimpse at a circuit! :W

[ThomasW]

I was also going to ask, would it help anything to squeeze in the woofers?

Any tigher and there's no baffle material between the drivers holding everything together.

[JonMarsh]

hi guys- made some progress on cross over assembly today- should have the first test run tomorrow morning.

Jon

[Jed]

hi guys- made some progress on cross over assembly today- should have the first test run tomorrow morning.

Jon

Wow Jon, you don't mess around when you're "on vacation." :T Looking forward to seeing the results of all your hard work.

[WillyD]

hi guys- made some progress on cross over assembly today- should have the first test run tomorrow morning.

Jon

Yay!

[ThomasW]

The setup ready for the XO build. Been a long day so I post more pics tomorrow.

[tyler]

The setup ready for the XO build. Been a long day so I post more pics tomorrow.

https://www.htguide.com/forum/attach...id=10283&stc=1

I can't wait to see more of the progress!

[JamesK]

That's an impressive workbench!

[exojam]

Sorry, but I just have to say, I love the phone. I remember those guys, always trying to get that last inch of line pulled. Going to another room and closing the door with the wire in there. Ah the good old days. Looking forward to further info on the design. I have all ready started laying the ground work with the wife concerning them.

[ThomasW]

Fueled with a stiff Peaberry double latte', we're building now....

[technimac]

How'ya gonna fit that cap in the foreground - y'know, the one the size of an oil drum - into the PE box? :W

Your production is mighty impressive. I can hardly wait to see the results.

Three cheers for the Denver Duo :T :T :T

[ThomasW]

How'ya gonna fit that cap in the foreground - y'know, the one the size of an oil drum - into the PE box? :W

The whole crossover is a design study of putting 10lbs of parts into a 5 lb can..... :B

Low tack masking tape to protect the dome tweeter from dust.



Notching the sides of the opening for the dome mid.

[ThomasW]

Occasionally I'm going to throw in a part of the build thread.

This is how the finished port looks when installed in the PE 1 cu ft box. The inner flare rests on the interior brace. The bead of hot glue stabilizes the end of the port. The port itself is glued together with ABS cement.



He leaves no holes unscrewed.... :B

[JonW]

Excellent thread! Very glad to see you two together and doing some of the fun things in life. :T

[Paul H]

Occasionally I'm going to throw in a part of the build thread.

This is how the finished port looks when installed in the PE 1 cu ft box. The inner flare rests on the interior brace. The bead of hot glue stabilizes the end of the port. The port itself is glued together with ABS cement.



He leaves no holes unscrewed.... :B

These pictures remind me of something - here :

http://bventertainment.go.com/tv/touchstone/homeimprovement/bios/Images/earl.jpg

[ThomasW]

It's alive....... :T :B




This is the 'first pass' FR plot of the crossover.... 8O




Parts is parts.....




AP test mic, it needs 200V of phantom power... 8)

[JonMarsh]

Ever had one of those days when I lot of niggly things don't cooperate?

This was one of those days when a lot of little things presented obstacles, from test cables that were left behind, a dead passive preamp, an an initially miswired low frequency crossover (oops! ops: ) that was spotted and rectified before testing.

However, overall, the net result of the first measurements of the completed crossover were much as expected from development simulation. We stepped through each driver checking the transfer function of filter and driver for midwoofer and midrange separately before combining the mid and midwoofer, then adding in the tweeter.

The final result before any tweaking came out fairly well:



In fact, considering that this was measured about 5-6 feet out into the room, and most folks will use it much closer to boundaries (which will elevate the low mids and mid bass, I'm not sure I want to go in and bring the midrange and treble level down to match. As is, it's within a +/- 3 dB window down to 80 Hz, so perhaps two versions should be published, this one for close boundary placement, and one with a skosh more attenuation for the mid and tweeter.

Using it as a mains standing up is not something I'm sure about yet- further off axis, there is a dip in the mid-tweeter crossover region.

Time to finish my guacamole break and maybe listen to it. :W

[ThomasW]

These pictures remind me of something - here

At least someone figured it out.... :T

[technimac]

Gosh, for a moment there I thought you two had solved the in-flight entertainment wiring glitch that's delayed production of the Airbus A380. :W


Congrats on your progress so far...lookin' good!

[ColoradoTom]

This was one of those days when a lot of little things presented obstacles, from test cables that were left behind, a dead passive preamp, an an initially miswired low frequency crossover (oops! ops: ) that was spotted and rectified before testing.

Using it as a mains standing up is not something I'm sure about yet- further off axis, there is a dip in the mid-tweeter crossover region.

Time to finish my guacamole break and maybe listen to it. :W

I was actually one of the little things that presented an obstacle today (I'm only 5' 9" :rofl: ) I was invited to see Jon and ThomasW at work (camp!)... my contribution was to "KEEP OUT OF THE WAY AND DON'T DISTRACT JON WHEN HE'S WIRING THE CROSSOVERS!!"

Since I am a noob at measurment - it was perfect timing for me as I arrived just as crossover work was completing and testing was beginning.

What I learned at camp today is:

The most time in speaker measurement is spent finding the adapters to the various cables used. :W

Two people can hold a conversation during the actual measurement process and still get reliable results! ops:

Guacamole is a great motivator! :T

JonMarsh and ThomasW know each other so well I think that they can actually communicate without speaking.


Thanks guys for letting me distract you for a couple of hours. ;x(


I was able to get two pictures of Jon that actually showed his face.... the first one is when he realized that the passive preamp wasn't working.....





the second one is his special speaker testing helmet! :rofl:

[---k---]

:rofl: Good Stuff.

BTW, I also had fresh Guacamole tonight.

[kingpin]

The most time in speaker measurement is spent finding the adapters to the various cables used. :W

:rofl: :rofl: :rofl: :rofl: :rofl: :rofl:

[tyler]

I was actually one of the little things that presented an obstacle today (I'm only 5' 9" :rofl: ) I was invited to see Jon and ThomasW at work (camp!)... my contribution was to "KEEP OUT OF THE WAY AND DON'T DISTRACT JON WHEN HE'S WIRING THE CROSSOVERS!!"

Since I am a noob at measurment - it was perfect timing for me as I arrived just as crossover work was completing and testing was beginning.

What I learned at camp today is:

The most time in speaker measurement is spent finding the adapters to the various cables used. :W

Two people can hold a conversation during the actual measurement process and still get reliable results! ops:

Guacamole is a great motivator! :T

Jon and ThomasW know each other so well I think that they can actually communicate without speaking.


Thanks guys for letting me distract you for a couple of hours. ;x(


I was able to get two pictures of Jon that actually showed his face.... the first one is when he realized that the passive preamp wasn't working.....

https://www.htguide.com/forum/attachment.php?attachmentid=10327&stc=1

the second one is his special speaker testing helmet! :rofl:


https://www.htguide.com/forum/attach...id=10328&stc=1

Tom, were you shocked that you didn't find something like this in the living room?

[TacoD]

Ever had one of those days when I lot of niggly things don't cooperate?

This was one of those days when a lot of little things presented obstacles, from test cables that were left behind, a dead passive preamp, an an initially miswired low frequency crossover (oops! ops: ) that was spotted and rectified before testing.

However, overall, the net result of the first measurements of the completed crossover were much as expected from development simulation. We stepped through each driver checking the transfer function of filter and driver for midwoofer and midrange separately before combining the mid and midwoofer, then adding in the tweeter.

The final result before any tweaking came out fairly well:



In fact, considering that this was measured about 5-6 feet out into the room, and most folks will use it much closer to boundaries (which will elevate the low mids and mid bass, I'm not sure I want to go in and bring the midrange and treble level down to match. As is, it's within a +/- 3 dB window down to 80 Hz, so perhaps two versions should be published, this one for close boundary placement, and one with a skosh more attenuation for the mid and tweeter.

Using it as a mains standing up is not something I'm sure about yet- further off axis, there is a dip in the mid-tweeter crossover region.

Time to finish my guacamole break and maybe listen to it. :W

Great work, what program are you using for your mobile measurements? For such a complex loudspeaker I think this filter already looks great.

[JonMarsh]

Hi Taco,

After listening a bit, I decided I will knock down the midrange and tweeter levels about 3 dB and try that out.

My "mobile" measurement setup uses Fuzzmeasure 2.0 for the Mac (Universal Binary). Fuzzmeasure 2.0 It's not designed just a speaker measuring product, but a little more general purpose than that. (It does other stuff useful to an installer, like room reverberation time measurements, delay measurements (useful for live sound) and CSD plots.

Like Praxis is uses a swept sine chirp convoluted to an impulse for gating and windowing; in the main measurement window it displays both the SPL response and the impulse response in separate graphs for each measurement. You can make and store multiple measurements and graphs in one project file, and you can drag and drop from one project to another, as well as select multiple measurements and create a common graph comparing or adding or subtracting them. Has nice features for graphing, including how it zooms in and allows you to pan a zoomed in area within the window to set the axis extents. It's quite easy to use and has some nice features; it doesn't do any type of distortion measurements at this time. Maybe version 3.0, who knows.

This is an older version pic, it doesn't show the current windowing controls.



I use it with a M-Audio Firewire Solo as the front end, which is bus powered from the six pin Firewire cable. Once you get the current drivers downloaded and installed, it's quite easy to use, has a nice control panel applet. Fuzzmeasure has a variety of inspector panes, including for configuration of the audio channels and hardware.

It's the easiest to use "mobile" setup I've been able to put together. Praxis is more powerful, but is more like flying an Airbus 320, where this is like an agile acrobatic plane with just a VFR instrument set.

~Jon

[JonMarsh]

After listening a bit to a pair, with modified crossover, I have to say that the RS52 is a very nice sounding dome midrange driver- or rather, that's it's just plain very clean and transparent. Whatever shortcomings this design may or may not have, it won't be because of the RS52. :T

Thomas just brought up an Aragon, to see how things fare with an upgrade from the Adcom ST545 to an Aragon 8008ST.

The bass tuning still needs to be sorted out- by the port output, it appears to have a rough port tuning of 26-28 Hz, a bit lower than I expect. When they're delivered to California, I'll have to run some impedance sweeps and check the tuning.

OK folks, we have a few minutes now with the 8008ST vs. Adcom 545. Thomas realized there was something he didn't like, and out of desparation he went down stairs and schlepped the Aragon up here, even though the temps in Denver today are kind of brutal. There's so comparison, so we can safely cross the Adcom's off the list of recommended associated equipment. :B :W

The Adcom was OK for testing, but I don't recommend it for music.

OK, I know most of the folks here are interested in these primarily as centers, but remember I do these science experiments in the service of music- music is my muse, HT my hobby.

Thomas and I are already discussing a bass bin setup to use with these for stereo music. These really get acoustic music and voice very nice, a good indicator for me of whether they're on target. :T

[Jed]

After listening a bit to a pair, with modified crossover, I have to say that the RS52 is a very nice sounding dome midrange driver- or rather, that's it's just plain very clean and transparent. Whatever shortcomings this design may or may not have, it won't be because of the RS52. :T

Thomas just brought up an Aragon, to see how things fare with an upgrade from the Adcom ST545 to an Aragon 8008ST.

The bass tuning still needs to be sorted out- by the port output, it appears to have a rough port tuning of 26-28 Hz, a bit lower than I expect. When they're delivered to California, I'll have to run some impedance sweeps and check the tuning.

OK folks, we have a few minutes now with the 8008ST vs. Adcom 545. Thomas realized there was something he didn't like, and out of desparation he went down stairs and schlepped the Aragon up here, even though the temps in Denver today are kind of brutal. There's so comparison, so we can safely cross the Adcom's off the list of recommended associated equipment. :B :W

The Adcom was OK for testing, but I don't recommend it for music. ;W

OK, I know most of the folks here are interested in these primarily as centers, but remember I do these science experiments in the service of music- music is my muse, HT my hobby.

Thomas and I are already discussing a bass bin setup to use with these for stereo music. These really get acoustic music and voice very nice, a good indicator for me of whether they're on target. :T

Sounds like you guys are having way too much fun!

I bet if you shorten that port an inch or so things might sound a bit more balanced at the low end. The RS52 definitely has my interest. It may be the best mid dome I've seen distortion wise. Haven't listened to them yet, but with PE free shipping this week that may change.

Do you find the little Vifa is "quick" or clean enough to keep up the the RS52? Same goes for the poly woofers.

I know, probably too early for reviews, but you've got me interested.

Awesome work!

Jed

[tyler]

OK, I know most of the folks here are interested in these primarily as centers, but remember I do these science experiments in the service of music- music is my muse, HT my hobby.

Thomas and I are already discussing a bass bin setup to use with these for stereo music. These really get acoustic music and voice very nice, a good indicator for me of whether they're on target. :T

It is good that you are considering these to be used for music and HT applications. My primary focus is also music listening w\HT being second. I can't wait to see the final results and the build thread of course.

BTW, the performance on the RS52 is very interesting indeed.

[exojam]

Jon,

I see you mentioned most folks maybe interested in these as centers. Do you see any issues with a L-C-R setup with these? Thanks.

[JonMarsh]

Hi Jed!

The integration of the Vifa and the RS52 is probably one of the real highlights of this design- I'd say it's doing a fine job of keeping up, and we're pretty much using in the area it's happy. BTW, the built up pair are using the new Chinese D26CN55, not one from my stash of "original" Vifa's. Neither the mid or tweeter are drawing any attention to themselves (must be something to Steen Duelund's concept here); the music is just there. Got Patricia Barber "Companion" on at the moment (MFL SACD). Just running a Yamaha carousel SACD player for now ("not" high end, but decent).

The crossovers are all outside the box, so the box volume is higher than the design value, which may account for the difference in planned vs current port tuning.

Hmmm, on to Allison Krause, one of long time favorites. Nice.

Did I mention these sound pretty nice on female vocals?

The D6.8 don't seem to have any problem with "speed" in their range (nominal 800 Hz crossover, but some contribution up to 1500 Hz), right now they're a bit over damped in the lower midbass, but the overall midrange detail with fast material like Kaki King's "Everybody Loves You" is more like headphones than a lot of speakers, so that's encouraging. (that's with an Aragon, too, so perhaps there should be some qualification- impedance probably dips to about 3.5 ohms). (Kaki has been likened to channeling Michael Hedges, and with no apologies or demerits in chops. She does more percussive stuff while playing on both the body and neck. )

This is the revised frequency response-




Now, it's Dave's True Story "Unauthorized Version", a Chesky SACD, and the focus an naturalness of timber is a step up from when we heard this earlier today with the Adcom. Great horns and vocals....


Of course, the next step will be getting the RS180 version together... I've got some more cabinets, and at least one set of "sort of" spare RS180's. I suspect the crossover will need to be a little more complicated, just to deal with the RS180 breakup. The RS52 peak is handled just by adding one cap to the mid low pass inductor to turn it into a CE notch filter at the 13 kHz resonance.

Well, it's been a heck of a week starting this Monday, when the first raw measurements were done, but I think we've made some good progress with this science experiment, uh,, I mean, HT Center Channel.

(They are not laying down as we listen to them, but standing...

[JonMarsh]

Jon,

I see you mentioned most folks maybe interested in these as centers. Do you see any issues with a L-C-R setup with these? Thanks.

This project originally started as a "forum request" in order to develop center channel using the RS52. In that mode, it would be laid down, the tweeter and mid stacked. So, I'm kind of "cheating" running a pair for music, but I'm quite pleased with the results. Actually, I'm going to be building 5 of these or 6, to equip my main HT and add a center to the bedroom system.

So, a L - C - R system should be right up the alley- that was what I hoped, but it wasn't the "original" agenda- you can read more about that in this thread. It covers the genesis of the idea.


OK, now we're spinning some vintage Stanley Clarke from "The Bass-IC Collection", which includes the only CD version of School Days with dynamics and frequency extension similar to the original 70's vinyl. (14 cuts from different stages in his career). Playing it pretty loud, and things sound unstrained.

[ThomasW]

Jon,

I see you mentioned most folks maybe interested in these as centers. Do you see any issues with a L-C-R setup with these? Thanks.

My guess is this picture will answer your question.... :T

[Dennis H]

Where can I buy some of those audiophile-grade five-nines polyethylene buckets for speaker stands?

[augerpro]

Looks good Jon! Nice to see a feasible 3way stuffed into that PE enclosure. how much do you think these weigh? My current center channel is just huge and I really don't care for that. These look much more acceptable.

So you used the Deuland concept for these? How closely were you able to follow the slopes? Any problems incorporating BSC with this sort of filter? What value for aleph did you use?

[JonMarsh]

Because the midwoofers and midrange aren't acoustically aligned, the lower side of the crossover strictly speaking isn't a Duelund. The upper side worked out quite well, though. BSC is just a compensation to realize the acoustical target, no more difficult than for a typical Flat Delay Bessel 4th order, which was the basic target used on the LF network.

This was the starting target and crossover points, other data is in the "Obi Wan you're my only hope" thread.

More later, gotta run to the airport.



Speaker Camp is closed for the week, but the thread isn't. :W

My Forcse sense indicated that with the range of acoustic targets already built in to LspCAD, it should be possible to realize one of the more usable Duelund alignments in a three way configuration, without a MathCAD generated reference target. This is because Ingemar offers flat delay filters (minimum group delay) in both 2nd and 4th order. Flat delay is a characteristic of the lower order coefficient Duelund alignments.


This was undertaken as a mental diversion from my normal responsibiities- the basic results and method posted below for those interested in dabbling with this without a major time and intellectual commitment.


This does not include having to use driver data with baffle step fall off and the other usual irregularities- those are dependent on the drivers chosen and the cabinet design. This is merely to describe the basic filter impelmentation and targets - much like the difference between a text book LR4 two way, and what you have to do in the real world to pull off the complete design.

The basic target functions are derived from the LspCAD Flat Delay functions- the LP target is the Flat Delay 4th order with a Fs of 1000 Hz, which hits the target -18 dB level at ~1.6 kHz, and the HP Flat Delay target with Fp set to ~2200 Hz, again hitting the -18 dB crossover target at ~1.6 kHz.

The midrange target is somewhat more difficult, as it must be generated from the combination of HP and LP 2nd order Flat delay targets; the LP set to 1400 Hz, the HP to 1600 Hz, and the target level adjusted for the peak at ~ -3 dB.

Components can be calculated from the Duelund equations, or use an LR4 and LR2 networks as the starting point.

The basic network result is shown next:



As these are idealized drivers, with simple impedance, there are no zobel networks or equalization used in this demonstration. The network configuration for the bandpass is my preferred configuration for 2nd order bandpass. I do not recommned cascading two conventional filters.

After the LP and HP networks have been optimized to the Flat delay targets, and the bandpass likewise for the synthesized target, response is close, but still with a dB or so ripple- this is because the flat delay target is not exactly equivalent to the chosen Duelund (aleph = 2.828), but very close. The final step is to optimize ONLY the bandpass components, and setup the target as flat response between 200 Hz and 10 kHz, to bring the midrange passband into compliance.


The result will look like this-




The relatively low Q crossover transistions have higher impedance than most "conventional" filters in the transistion region, and the network impedance even with a 4 ohm target woofer was at or above four ohms at all frequencies. How that will fare in a network with BSC and driver equalization is yet to be seen, but my Force sense is optimistic...

Note that through out the overlap range the drivers are in phase (midrange is wired backwards), and reversing the midrange produces the expected nulls.

Note the phase characteristic- All Pass- with one 360 degree phase rotation between 20 Hz and 20 kHz.

There is one more important determination to make regarding this approach, of course- how does it sound, based on the network impact on power repsonse?

The above was a target function- not the network ultimately used for the speakers including the influence of driver behavior, though it's very similar.

[Dennis H]

Speaker Camp is closed for the week,

Man, Jon, you shame me. My idea of a vacation is lying on the beach watching bikini babes. Yours is doing more work than most people would get done in a month.

[exojam]

Very nice. Thanks for the reply.

[ThomasW]

Man, Jon, you shame me. My idea of a vacation is lying on the beach watching bikini babes. Yours is doing more work than most people would get done in a month.

Given the record setting heat and the workload, it was more like a Roman slave galley than a vacation for all parities involved.... :gah:

The pay-off however is a set of very good sounding speakers in comparatively 'small' boxes... :T

[JamesK]

No air con?