Driver Evaluations for a new project

[Scottg]

..given the recent Dayton disappointment, was the Dark Lord aware? of these:

https://www.parts-express.com/peerless-by-tymphany-gbs-115n25al01-04-4-1-2-aluminum-dome-woofer-4-ohm--264-1484

https://www.parts-express.com/peerless-by-tymphany-gbs-85n25pr03-04-3-1-2-paper-cone-midrange-4-ohm--264-1494

..of course I doubt they will offer the sort of subjective performance that the more expensive *Morel will provide, so this is just a sort of "helmets/heads-up".

*and likely the Satori dome mid..

[augerpro]

Great timing: https://www.madisoundspeakerstore.co...dome-midrange/

Comparative measurements against the Morel and old RS52 would be awesome! BTW, if the mounting flange won't fit the cabinet, but can be removed, I can design and print a new faceplate and ship asap.

[augerpro]

Looks like the MD60N was intended as a drop-in replacement of the Morel 1308, flange diameter and bolt circle are identical.

[Evil Twin]

..given the recent Dayton disappointment, was the Dark Lord aware? of these:

https://www.parts-express.com/peerless-by-tymphany-gbs-115n25al01-04-4-1-2-aluminum-dome-woofer-4-ohm--264-1484

https://www.parts-express.com/peerless-by-tymphany-gbs-85n25pr03-04-3-1-2-paper-cone-midrange-4-ohm--264-1494

..of course I doubt they will offer the sort of subjective performance that the more expensive *Morel will provide, so this is just a sort of "helmets/heads-up".

*and likely the Satori dome mid..

Yes, I am. Parts Express is not a good source for the more off the beaten path Peerless parts- Digikey, for example, has the GBS-85N25PR03-04 in stock, as do I.

In this case, form factor for the cabinet already built was an important factor, especially considering the press of time. Future investigations will look further afield when time allows. With the current test system, the physical parameters narrowed down the choices quickly.

[Evil Twin]

Looks like the MD60N was intended as a drop-in replacement of the Morel 1308, flange diameter and bolt circle are identical.

An astute observation, and one I made also from the early data- most unfortunate that the low frequency extension is lacking in comparison...






Measured response with the crossover to be tested in system, showing with and without the RLC EQ for the 1500Hz region bump:

[technodanvan]

Altogether, a dozen were discarded today.

I'm currently imagining a small business running off your trash can.

Steen Duelund developed a closed form equation set....

One of the problems I've had with understanding the Duelund concept is how one then turns these graphs into a crossover. I imagine you can extrapolate approximate crossover frequencies and slopes from the final graph, and then it is just trial and error in the form of measurements? I believe you use a sort of series crossover design during your process, but can the same be accomplished using a parallel crossover?

[augerpro]

An astute observation, and one I made also from the early data- most unfortunate that the low frequency extension is lacking in comparison...

Yeah. Still would love to see a comparison with the Morel on a measurement system I trust.

One of the problems I've had with understanding the Duelund concept is how one then turns these graphs into a crossover.

There is a spreadsheet for the filter values, and Soundeasy (and others) can pull in those values as target slopes.

[Evil Twin]

Refer to Steen's papers. He gives equations for calculating starting values- then, given that drivers and impedances are non ideal, those values need to be adjusted. This must of course be done in reference to the master transfer function, which is defined mostly simply- just by the center frequency and the aleph gain coefficient.

All of this is spelled out in Duelund's paper titled "The Art of building a loudspeaker to the end". I found this over ten years ago, but I do not recall where.

If anyone has trouble locating this, send me a PM with your email address and I can forward it to you.

[Gerald Jansen]

I guess the mentioned Duelund's paper titled "The Art of building a loudspeaker to the end" can be found at:

https://duelundaudio.com/wp-content/uploads/sites/3621/2013/12/duelund-filter.pdf

[Bear]

Refer to Steen's papers. He gives equations for calculating starting values- then, given that drivers and impedances are non ideal, those values need to be adjusted. This must of course be done in reference to the master transfer function, which is defined mostly simply- just by the center frequency and the aleph gain coefficient.

All of this is spelled out in Duelund's paper titled "The Art of building a loudspeaker to the end". I found this over ten years ago, but I do not recall where.

If anyone has trouble locating this, send me a PM with your email address and I can forward it to you.

I did this a while ago, so no warranty, express or implied, nor any claims of merchantability or fitness of purpose.
Duelund.zip

[Zvu]

Amir Majidmehr measures the hell out of (in between other things) loudspeakers and recently this was measured:

https://www.audiosciencereview.com/forum/index.php?threads/hivi-3-1a-diy-speaker-with-sehlin-mod-review.15802/

It uses HiVi dome midrange which performed really well under stress.

https://www.aliexpress.com/item/32810919938.html

https://www.parts-express.com/hivi-dmn-a-soft-dome-fabric-midrange--297-415

Now i know that in this case there is a need for a bit more extension down low, but i think that this one could be used in one of the iterations.

https://ampslab.com/blog/2020/04/20/hivi-dmn-a/

[Evil Twin]

SB26CDC-C0004 revisited

This is a follow up on the SB Acoustics SB29CDC-C0004, which I noted in early 2019 has some interesting characteristics, and general performance at a level higher than it's price would indicate, compared with many other products from SB Acoustics or others. At that time, I was searching for candidates for waveguide use primarily, but also looking at flat baffle applications.

The web site data has been updated, including the frequency response plots. This raised the question of whether there was a useful update in performance, or if like some other vendors, things were deteriorating a bit. The web site data indicated improvements, but there is a local saying which I find appealing in cases like this- "In God We Trust, all others we verify."


Do not attempt to compare these results directly with anyone else's test- these were made on a specific test baffle related to the intended application, not on an infinite baffle. In particular, there is a "bump" in the response characteristic around 1kHz due to baffle step behavior- you can easily model this in Edge.


So, I shall share just a few of the more interesting measurements...


Polar 0-60 degrees, 10 degree increments




The polar response is promising in it's characteristic and smooth roll off out to 60 degrees... this is with the phase shield intact, as were all other measurements


For the planned/intended applications in HT, such as a center channel or small mains, a narrower off axis spread is of greater interest...

Polar 0-40 degrees




An important consideration in evaluation is the impedance curve, and whether there are artifacts present and if inductive rise is well controlled...





So far, quite promising... somethings similar to the March 2019 measurements, but the overall smoothness is better, and it's possible the phase shield design has been tweaked. It's also possible that my use of a felt rebate is superior to a routed rebate, but I question that, merely leave it open for investigation. I do not have the original test baffles anymore.


So, to a key parameter- distortion- any issues or surprises?





From 2kHz up, HD2 is at about -65dB, and HD3 is at about -75 dB. This is very satisfactory performance at 90 dB output. It is also substantially better than the last ones measured, especially in regards to HD2.



Perhaps a comparison to a previously measured more expensive model from SB Acoustics would be in order- a model exhibiting very "Scanspeak" like characteristics...

TW29BN




I think we may have a new contender, perhaps winner, in the "Under $100 tweeter that is the best $400 tweeter you can buy" category.

[Bear]

So, to a key parameter- distortion- any issues or surprises?


[ATTACH=CONFIG]30712[/ATTACH]

The data provided by my Bothan spies indicates that this should not be a surprise. Even the standard aluminum dome from Sienar Industries has claimed many victories over rebel scum.

I think we may have a new contender, perhaps winner, in the "Under $100 tweeter that is the best $400 tweeter you can buy" category.

Has it unseated the DA25, or merely providing competition? Similar laudits were directed at the DA25 not too many cycles ago.

[HiroPro]

Talking SB Acoustics Satori Be tweeters, has the TW29BNWG shown up on Coruscant yet? Looks like a very nice waveguide Be tweeter and I can't help but imagine how well it would pair with a Purifi PTT6.5W and passive radiator in a Helios/Buchardt S400 inspired design.

[JonMarsh]

I have done some tests on it- have a pair. I’m out of town right now, though...

the polar behavior is disappointing.

[HiroPro]

Hi Jon. Thanks for posting the bad news LOL. Uh what's the deal with the polars? BTW I can't help but wonder if Evil Twin is you and if not who is it?

[Bear]

Talking SB Acoustics Satori Be tweeters, has the TW29BNWG shown up on Coruscant yet? Looks like a very nice waveguide Be tweeter and I can't help but imagine how well it would pair with a Purifi PTT6.5W and passive radiator in a Helios/Buchardt S400 inspired design.

There are a few different threads bouncing around, so it's hard to remember which one this was discussed in. However, for similar money, the Bliesma T34A in a Jantzen waveguide was a substantially better performer for about the same money. Realistically, since it can play down to 1300Hz without the waveguide, it would be a MUCH stronger candidate for a Helios-inspired design that was not a vendor showpiece. The best-of-breed at a similar budget that makes sense to me would be:

• Bliesma T34A
• Jantzen Waveguide
• WO24P
• ScanSpeak 26W passive radiator

In 35 - 45L, this would trade the as-designed impulse response for a substantially heavier bottom-end. I went with ~40L as my target to trade a touch of bottom end for a little more safety on the Xmech. If one wanted a more budget-friendly option, then something like the SB26 in one of Augerpro's larger waveguides would be a strong value play.

[HiroPro]

Thanks for sharing the info on the T34A/Jantzen combo. That tweet sure can drive low and is a great candidate. I wonder how well the T34A would run in a SEOS-8 dome tweeter waveguide if mountable. I haven't seen any dome SEOS builds so that might be an interesting option.

[Bear]

Thanks for sharing the info on the T34A/Jantzen combo. That tweet sure can drive low and is a great candidate. I wonder how well the T34A would run in a SEOS-8 dome tweeter waveguide if mountable. I haven't seen any dome SEOS builds so that might be an interesting option.

I think that the Dayton RS28 may have been popular among the SEOS crowd, but I haven't looked into that one in a while. The Jantzen waveguide is designed for a SEAS tweeter, but it apparently works quite well with the T34. If you want to spend more money, go beryllium. The Jantzen WGs are Not Cheap, but they seem to be very effective.

[5th element]

The SB29CDC-C0004 is insanely good. It reminds me of the good old fashioned, narrow surround, D2905/97 and 99. I do not understand why companies though this move to the wide surround was a good idea. It's not.

[HiroPro]

The SB29CDC-C0004 is insanely good. It reminds me of the good old fashioned, narrow surround, D2905/97 and 99. I do not understand why companies though this move to the wide surround was a good idea. It's not.

That very much seems to be the case when I look at the performance of the BlieSMa tweeters with their narrow and concave surrounds. The off axis for such a large dome is really impressive. I had in mind a waveguide design using the SB tweeters but after looking at the BlieSMa and Troels Gravensen's work I'm thinking the AlMg T34A-4.

[augerpro]

Jon, if you ever have some time, could you get me dimensions of the Satori Be diaphragm? I'd like to start modeling it in ABEC?

[JonMarsh]

Hmm, I've been gone to Idaho for a logistics run this weekend, but you guys have been busy! Just got back late last night, and packing to head out again tomorrow with a trailer load.

First, let me enthusiastically endorse Matt's specific comments... surrounds are just as much a challenge for tweeters as for mid woofers and dome midranges, and the skinnier, the better, if other factors are managed appropriately. At least that way, there's less radiation from it. Also, I have a "hunch" (can't dignify it by calling it a theory) that larger surrounds get in the way of the coupling you need working into a waveguide.


So, to comment a bit on the DA25 vs. SB26CDC, the DA25 is just as good as it's always been. And it's a tad less expensive. But, as tweeter's go, it's ginormous, due to the large diameter magnet. This can be a problem for some applications, especially with higher crossover frequency overlap. Of course, it needs an ultrasonic trap to bring the resonance amplification of distortion product down. The distortion isn't quite as low down at 2kHz running raw, as the two SB26CDC I have on hand, but it's still very good. As used in the Calliope, it's certainly not a problem.

So, just to part the curtain a little bit on some work I'm doing for Steve, ponder this picture...




On the left is the Satori tweeter+ WG assembly. On the right, is a German made low cost waveguide, with a BlieSMa T34A.


Below is the measured polar response of the Satori for 0-60 degrees on a 10" wide baffle. This tends to boost the output in the 1kHz area; don't compare this measurement to infinite baffle. For me, the point of interest is how well the curves track and the degree of separation at say, 10kHz.





I have a pair of T34B which are planned/in the queue for a similar configuration test. This work is being done for Steve and ET. I hear mumblings about a reborn NatalieP Ultra... scary stuff... reborn Star Wars references don't always end well....

I will go so far as to say that the 10kHz tracking for the T34A is quite a bit better... over 10dB better. And we know what a monster the T34 motor is in the low end, so something like a 1600-1700 Hz crossover could work pretty well... managing the baffle design might be the interesting part.
The difference is kind of like the difference between a Faital LTH142 horn/waveguide I tested an an 18Sound XT1086.

With the relocation effort seriously engaged, the next few months won't be very productive on this front... but early 2021 should be a different story.

Auger Pro, I'll see what I can do for you on the dimensions... might be a bit tricky.

[ergo]

Hi Jon,

Very interesting. Would you be willing to post a measurement set for the right combo too - Id assume the alu dome Bliesma would be quite similar to Be version below 15k?
And is it the Monacor WG300 on the right or is it something 3rd I don't know about?

[Bear]

Hi Jon,

Very interesting. Would you be willing to post a measurement set for the right combo too - Id assume the alu dome Bliesma would be quite similar to Be version below 15k?
And is it the Monacor WG300 on the right or is it something 3rd I don't know about?

See back to post #272. It's the Jantzen WG.

Also, some additional performance data was posted here.

[ergo]

Thanks Bear, I had missed those posts.

What threw me was the "On the right, is a German made low cost waveguide, with a BlieSMa T34A." - I believe the Jantzen one is made in Denmark and Monacor is german - hence the confusion.

[JonMarsh]

Though I’ve done a lot of testing with the Jantzen waveguide, for many tweeters, this combination shown above is with a Visaton waveguide. I’m on logistics travel most of this week but I can post some measurements later, around the weekend.

[Bear]

Though I’ve done a lot of testing with the Jantzen waveguide, for many tweeters, this combination shown above is with a Visaton waveguide. I’m on logistics travel most of this week but I can post some measurements later, around the weekend.

Thanks! I had thought that the Jantzen version was the WG in question. The Visaton 148 is pretty cheap in comparison. That may be a (relative) bargain as a package.

[Zvu]

...I do not understand why companies though this move to the wide surround was a good idea. It's not.

I'm not sure that wide surround is a bad idea per se. I've listened Peerles DX25 and it sounds and measures great. It looks to me that wider surround impacts breakup for soft domes and that can reflect on off axis behaviour if done right.

https://hificompass.com/en/speakers/measurements/vifa/vifa-dx25tg09-04

https://hificompass.com/en/speakers/measurements/scan-speak/scanspeak-d3004660000

https://hificompass.com/en/speakers/measurements/scan-speak/scanspeak-d3004/602000

https://hificompass.com/en/speakers/measurements/scan-speak/scanspeak-d2608/913000

https://hificompass.com/en/speakers/measurements/morel/morel-mdt32s

https://hificompass.com/en/speakers/measurements/bliesma/bliesma-t25s-6-pre-production-sample

Not sure about wide surrounds on hard domes though. I really don't like how that Satori Be tweeter measures.

@JonMarsh: Regarding waveguide coupling, Heissmann got very good results with Peerless DX25 using Monacor WG300. Maybe that waveguide is worth a try.

[JonMarsh]

Thanks for the reminder, Zvu- the Monacor is on my to-do list, but with relocation efforts underway and taking priority, it will be a while, in all likelihood...

[Evil Twin]

Nero-6mrn150d

Matters are becoming more settled in the outer rim, enough that the resumption of test activities is not only warranted, but mandated.

As I generally prefer, let us examine some impedance data for what is believed by some to be a promising new midrange driver...








Now, the impedance data is not reviewed without concern...





But one thing it clearly reveals.. if you took it... with the DATS system, the excitation current is quite low, and the driver SPL is also... but in this case, the claimed sensitivity bears no questioning, given the high playback volume during the sweep...

Combined with the high Fs, this opens up some interesting equalization possibilities for those occasions when the full playback sensitivity is not required.

But close examination of CSD plots will be needed, given the observed resonance at 2kHz.

[5th element]

Well the resonance at 2kHz was to be expected, it's there on the datasheet and in the review that audioxpress did. The one at 800Hz is less evident but is nevertheless obviously present.

If you read the Audioxpress review you will find that the suspension is so stiff that the coil has difficulty getting itself out of the gap even when over driven. At least that's how I read it. I guess it would act like a kind of automatic compression, not that you'd expect this limit to be reached in a domestic speaker when properly crossed.

It looks built like a tank though with ventilation in all the right places.

I quite like the idea of removing the dust cap and seeing what the situation might be for turning it into a coax :P It would have been very nice if SB had included full copper in the gap though.

[fatmarley]

Yeah this is shockingly bad. You sure it's not something to do with the dome venting and/or stuffing issues on the chamber?

It looks like you were right (Page 10, Post #330). I cut the back off one of my Dayton RS52NA mids and played around with various types of stuffing. With 2 x 10mm thick 100% wool felt discs fitted tight against the driver (there's mesh to stop anything touching it) and sat on a large block of 50mm acoustic foam, the 1.8khz impedance peak is smoothed out. I took a quick frequency response measuremement and found the dip filled in but it's caused small peaks and dips elsewhere.

I'd say there's a good chance of achieving a flat response with the correct chamber and stuffing. Something similar to the B&W style mid enclosure that you use (or used?) would be well worth a try. It's something I'm going to experiment with a bit more when I get back from holiday.

One thing of note, whilst searching around for pictures of the RS152NA internals, I noticed that they used to use a yellow stuffing that looks suspiciously like fibreglass. Mine have what looks like white polyester stuffing. Hmmm - where can I buy a small bag of fibreglass?

[JonMarsh]

You might try looking for fiberglass used to wrap pipes- they're pretty small bags, places like Home Depot carry them.

[fatmarley]

Not sure if you can buy fibreglass pipe wrap on the UK. Stealing some from our loft is a possibility, but I've never been up there, so don't know what type of insulation is used.

[JonMarsh]

Not sure if you can buy fibreglass pipe wrap on the UK. Stealing some from our loft is a possibility, but I've never been up there, so don't know what type of insulation is used.

well, I'll concede I've never been in a big box store in the UK, and not even in Germany, though I was tempted to a few times out of curiosity. Have a look... it all depends I suppose on what local practices are.

[5th element]

It makes me wonder if the changes to the mid were brought about by wanting to shift away from fiberglass. Seems like a really bad choice as it's performance goes from excellent to ugly.

I've no idea where you can get it from in the UK.

[fatmarley]

Just found this (post #24) : http://www.htguide.com/forum/showthr...sts-and-tweaks

So it was full of fibreglass.

I'm back from our short break. Not sure if anyones interested, or if I should start a new thread, but I can post results of a fibreglass filled chamber when I get the chance. Interesting to note that someone else in that thread suggested a B&W style enclosure.

[fatmarley]

On holiday, I found some funnels that looked about the right size, so I bought a couple.
I pushed three 10mm felt discs in tight, 50mm acoustic foam and some loose wool stuffed in. The blue tack I used to temporarily join the funnel to the tweeter enclosure only just held when pushed hard because everything is crammed in very tight. As you can see, the impedance peak is gone.
The right hand pic is now glued together with a glue gun.

Impedance before mods -







Typed in the numbers on the label and found the funnel at CPC - https://cpc.farnell.com/whitefurze/h...nel/dp/SI18690

Ordered some silencer fibreglass wadding from ebay. 10mm thick sheet, so should be easy to cut the right sized discs to wedge in tight - https://www.ebay.co.uk/itm/133668535468

Also ordered some A-Glass Long Strand Fibre Glass Wool - https://www.ebay.co.uk/itm/111944393...r=410891458078



Not sure why there's a peak at 3khz now



Just for comparison, here's the unmodified driver response:

[Evil Twin]

Just found this (post #24) : http://www.htguide.com/forum/showthr...sts-and-tweaks

So it was full of fibreglass.

I'm back from our short break. Not sure if anyones interested, or if I should start a new thread, but I can post results of a fibreglass filled chamber when I get the chance. Interesting to note that someone else in that thread suggested a B&W style enclosure.

Sharing could be quite useful- please proceed.

[Evil Twin]

New drivers for testing soon...

My logistics efforts between the galactic core and the outer rim continue, and will still continue for a while, as my Imperial shuttle does not have the carrying capacity of a Star Destroyer.

Just yesterday night I returned to find an expected shipment and one which was a small surprise...




These are new midrange drivers from PuriFi to evaluate, ordered direct, and at last the new Epique 7" drivers.


Both cartons were heavier than their appearance might lead one to expect... but the Dayton carton won in the weight category.





The factory data is... interesting. Several possibilities are suggested, with the right design approach. Sensitivity for a single driver is low but not exceptionally so, and a parallel pair will approach 90 dB.





And then there is the "dark horse" driver, probably not as well known, but possibly of integral importance to one ongoing and one future effort...

[Evil Twin]

Now, for those willing to cast aside brand purity and loyalty, imagine what might be possible combining these two... Ardent PE(TM)? (Trademark belonging to the creator, Steve Manning.)

The gating issue would be detailed comparisons of the PuriFi woofers on hand and the new Epique. Though for a somewhat budget oriented build, the Epique could remain intriguing even if they are out performed by the PuriFi in some areas, such as IM distortion, as long as they perform well compared with "conventional" driver solutions.

[5th element]

I do love the look of the epique.

[JonMarsh]

Handsome is as handsome does, but I do agree.

[Bear]

Interesting that it's being marketed as a subwoofer. A small subwoofer, though. I'll be curious how it stacks up against the 7" Anarchy, as well.