Some speaker driver measurements...

Throwing out some ideas... ScanSpeak Revelator 18M4631T00, an older design but still very relevant. Eighteen Sound 6ND430 is another one. Its a short list !
Here's what I'm getting out of 6ND430 and a Wavecor TW030WA11 measured at 12" on center crossed at about 1800hz. I had to use 10db increments because the distortion comes out too low for 5 DB. The 350hz peak is the table vibrating not the speaker. The raw response is pretty close to manufacturers data. I use an active crossover at about 300hz to a TD15S. Distortion on this pair is a little higher than the horns I use.

TBH, I'd consider the Dayton RS180P-8 over the 6ND430. I did XSims with the RS180 and TW030WA11 and was able to produce a little better response crossed at 2200 which is a little better for the tweeter, about the same sens, probably still low distortion to 200hz and cheaper. If the calculated reference efficiency for both speakers is compared they're about 89 db each and the rs180 doesn't have the rise. The RS180 is easier to use.

It is hard to find a good midrange under 200.00.

 

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The box is an old MCM prebuilt I've used for many different ideas. Once I figure my final direction, I'll recut the front baffle and integrate the system into one box.

I went in this direction due to natural issues with the bass box and woofer. The box has two internal nodes at around 300hz giving me a dip in the response and phase glitch at around 300. Second, the woofer has the typical cone\surround interaction resonance giving a dip or peak at 450ish hz depending on the measurement angle. There's also a slight distortion peak at 450is but a distortion dip at 300ish. Keep in mind the distortion peak is still well under 1% in fact it's under 1% at deep bass frequencies at loud levels. So I choose a device that'll keep up with the woofer and cross just below 300hz. At the time the 6ND430 was a top contender and still is.

The tweeter is simply an all around great tweeter. Easily used over a range of cutoff frequencies. Any cutoff needed from 1500 on up can be designed with a reasonable network.

The rise in response makes the 6ND430 a little harder to use and to obtain a nice frequency response I ended up with a simple 2mh 20 uf crossover. I little lower than I wanted but anything else I simulated or measured is worse. More complexity didn't show improvement. So I stuck with the simplest crossover design. One of my goals was to use each device within it best operating range. To get best overall frequency and phase response I'm pushing the tweeter below it's 2200 sweat spot. Keep in mind the distortion peak at 1500hz ish is still very low.

Sonically it's neutral. Very good sound stage, imaging and immersion. Individual instruments have very good detail. Vocals are a little recessed (compared to the horns) but have almost no artifacts. It's hard to hear Esssing, Tching, tiz or sizzle. If I hear any artifacts I now blame it on the recording. LOL Vocals sound deliberate, articulate with inflections intact. It's very listenable and at moderate to loud levels without fatigue. Dynamics again are very good. Punch is a little fuller than the horns. The horns have a little sharper snap, It's hard to beat the dynamics a 3" diaphragm horn brings to the system. Treble sound more extended than the horns and clean clear and BIG like cymbals sound.

The horns do bring a little more high frequency dynamics and a little different punch. Also, more forward vocals. And sometimes seem a little more immersive. YMMV

AS for specific music:

Nora Jones, "Feels Like home" has very good walk around sound stage, articulation and tone. Piano walks across the sound stage. Other instruments pop out around the sides and top. There is an uncanny deep bass studio ambiance with studio noise and mistakes easily heard. Same with Boz Scaggs Dig.

Ray Charles, Genius Loves Company, Very good vocal articulation and instruments poping out around the sides. Some small percussion sounds like it's coming straight from the right side of the room.

Galactic, is very dynamic. big massed horns are very articulate easily identified and vocals remain intact. Massive punch of course.

Southrn Culture on the Skids and Noth Mississippi All Stars, very dynamic, all guitar and vocal affects are heard and identifiable. Guitar sounds are big and real.

Tank and the Bangas has all kinds a small high frequency instruments and sounds popping out and moving around all over the sound stage. The busy back ground vocals remain articulate. Powerful punch and deep bass that rolls across the room. The nicer pop songs remain sweet and any vocal affects are easily heard.

Steely Dan Everything Must Go. Of course massive punch, chimes across the sound stage. Uncanny bass ambience and what I think are mistakes are easily heard.
 

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Hi, very usefulll inputs, many thanks Scholl.

SO I assue you're talking about the 8 ohms unit. How much sensivity did you get with your circa 300 hz cut-off please ? It is really around 91 dB/2.83V at 300 hz w/o XO ? All the measurement I saw on the web show not real concistency there. I stuck on Dibirama measurements which with Hificompass, Zaph and AUdioexcite among the rare good sources. http://dibirama.altervista.org/home...und-6nd430-8-mid-woofer-6-8-ohm-500-wmax.html

While it is a midwoofer, it has good review sounding wise. the 18M Rev from Revelator is quite appealing but foam surround. As some Monacor paper or Audax paper as well : http://dibirama.altervista.org/home-page/mid-range/205-audax-pr170m0-mid-range-6-8-ohm-200-wmax.html

http://dibirama.altervista.org/home...sp-6-100pa-mid-woofer-6-5-8-ohm-200-wmax.html

Also (courtesy of ScottG diya fellow : http://dibirama.altervista.org/home...-hm170c0-mid-woofer-6-5-8-ohm-120-wmax-2.html

6" that are usable still to 2K hz with still good disto numbers till that frequencies are not many ! with a little efficienty I mean !
 
TBH I don't know for certain because I don't have a calibrated SPL meter. The calculated reference efficiency is 91.9db I was wrong earlier. I use a two ohm resister to level match the Wavecor which is a 4 ohm version which is 94 db I'm guessing the final sens is 91db and it could be ond db higher or lower.
 
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If using as desk-top speakers, how tall a stand-off from the surface is needed(of course, the PRs will need adjusting too)?
I find it difficult to answer how tall a stand-off from the surface is needed. I don't think the PR will need to be adjusted, but the overall tonal balance will be changed towards low frequencies because the baffle-step effect is reduced.
 
I'm not sure what JBL have done with the M2 as it was tested by Erin but the crossover does not look the same as it does in their own measurements.
A 15" pro woofer should not be in break up at 200 to 500Hz and if you look at the measurements of the driver itself it is not.
https://manualzz.com/doc/37151866/eds-9990013-jbl-2216nd
Almost the same driver used in the 4367 with a passive crossover looks much flatter in that region in Erin's measurements. Most 15" drivers have some wiggle in the 500Hz region from cone/surround issues.


It is the size of the driver more so than the waveguide, the M2 has a 1.5" exit driver, a 1" driver would push this up but be less able to deliver as much SPL at the lower end.
15s can have a cone edge resonance issue at the 1/4 wavelength on the cone length. Typically, 400-500 hz. This can be seen in some measurements as a dip or ripple in the response depending on how it's measured. The AE TD15S shows up right at 450hz.
 
I'm working on a new reference measurement speaker for a customer, now in prototype phase.
Prototype MUC.jpg

I destroyed a Bliesma M74A midrange driver during my tests ... so this measurement data was expensive. o_O
(1s sweep from 500Hz to 20kHz at 27V - about 125W. I thought the 3" coil should be able to take this, the 2nd one is perfectly fine. Contacting Mr. Malikov at the moment, let's see if this was a faulty model. But >120dB/1m IS pretty loud ...)

Measurements in 0,5m but SPL level calculated for 1m distance. At low frequencies you have room influence, windowing is 0,5s.

Frequency response of the 3 ways at 2,83V.
FR speakers 2-83V.png



SB34NRXL75-8, 2pcs in parallel:
FR TT Level.PNG

THD TT Level.PNG


Bliesma M74A, 2 in parallel:
FR MT Level.PNG

THD MT Level.PNG


And Blisma T25B: - scale up to 50kHz!!!
After my experience of destroying the 3" I was gently with the level - normally it should take higher voltage for 1s.
FR HT Level.PNG

THD HT Level.PNG


Looks like an easy match for the crossover network.
The only sad thing with this project ist - this speaker will never play musik. It's here for sweeps from 16Hz to 100kHz only. :cry:
 
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okay, please be careful with measuring tweeters with long sine sweeps or even long MLS signals.

Real music is dynamic in nature and does not stress midranges and tweeters like long test signals.

If you must do testing at 110+ dB/1m, keep the signals short eg. Closer to 1 second second, not 10 secs. And give plenty of time to rest (eg. >1 min) between sweeps.

The dome/cone excursion May handle it but not the voice coil. Otherwise you will let out the magic smoke.

Eg. Doing sweeps at 2.83V, and stepping up the voltages to 20+ volts with long sine sweeps to stress test the driver… well… consider that a scientific experiment to determine failure point.

Ask me how I know (but did it with a €30 driver not a €300 driver). You can do it with a €3000 driver that not my business but just be aware that the problem remains the same.

Once is an accident; twice is foolish…
 
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