Driver for JBL 708-ish dimensioned 2-way

With all due respect, this is the least helpful comment.

I am living in an active world and after gauging what the Pros did to their driver/enclosure combis, I am more confident than ever this is going to work out all fine. Le or box alignments do not matter, the response will be equalized anyway. Please do not congest the thread with analogue premises.

I invested a lot of time to narrow down drivers, I need comparative remarks for these four drivers with equalization as per WinISD and the given use case, which is active 30 liter box.

Yes I understand its a active system.

The reason why I suggested modeling the speakers to standard QB3
alignments.
Is so you see whatever driver works well in a smaller box.

Having a lot of experience with live sound drivers.
I was giving far warning that its typical for some to have a lot
of cone breakup.

Hence also if your going to force a driver that might not be happy
in a small box, and then apply more additional EQ to increase bass.
Your also going to encourage more cone breakup.

then again your making judgments at full max power when at home you wont be using more than 5 to 15 watts.

If a live sound driver is more designed for bass not midbass.
MMS or cone weight can clue you in. Usually have a heavier cone
to reduce cone breakup, or a ridge cone, which helps reduce cone breakup.

Anyways the 10G40 seems to be more optimized mechanically for smaller enclosures.
And has a much heavier reinforced cone. almost 60 grams
compared to the others with 40 to 50 grams.
DSP can correct a lot of things, but if your apply high EQ to gain
bass. It will also produce more cone breakup, which WinIsd will not show
you.
Its why I suggested to look at QB3 alignments, even if you not using them.
Since it will clue in what driver is likely more happy in a smaller box.

Also you seem to be aware of net vs gross volume.
Keep in mind some of the speakers have rather large magnets.
To make such heavy cones work.

Overall displacement of these drivers might be 3 to 5 liters.
and your port area might be 1 to 3 liters as well.

So im sure your aware if you still want a 30 liter cabinet according to the model. Your box might have to be 35 to 38 liters.

And if you do plan to keep the box at 30 liters, then your concerns for
excursion levels would be modeled around 24 to 27 liters.

Also your using max power in winisd, at home you wont use more than
5 to 15 watts. Likewise with port velocity, the ports will be much smaller
and you would only need ports to support 20 watts not 200 watts.
But again since your using EQ to boost bass. Its a good idea to check velocity
with EQ applied.

Also a Reflex / Ported cab reduces cone movement at FB.
And will also unload quicker below FB / tuning frequency.

If your models are using typical 50 to 65 Hz tuning for a 10"
you might try using a low tuned reflex like 27 to 35 Hz
to see if it reduces Excursion with added EQ

Also with a 4th order highpass tuned around 25 to 27 hz added to your model
will reduce unloading or cone excursion. and increase max power.

Its the great thing about DSP, is adding subsonic or over excursion protection
is rather easy
 
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Thank you for your detailed reply. Why I dismissed you considerations about Le was that I only had the notion it would tilt down the mid range and upper mid range response. After reading in a thread by b_force, I also learned it can be responsible for distortion. That was new to me.

One thing is twisted in your reply: The highest Mms is that of the PHL audio 3411. This is also a black hole in some domains: If I could get a confirmation that this is the driver used in Genelec's S360A, which I use as a sort of model at the moment, the sum of applauding reviews available online left me without a doubt about its usability for mid range duties in a two-way. I have asked their lead engineer for confirmation, but naturally do not await a response. Sadly, there is even no linear distortion measurement available to my knowledge, which is a problem. I have emailed PHL audio and hope they would at least provide a frequency response, but they do not have the reputation to answer such inquiries.

The Beyma 10G40 has actually a bit lower Mms at 52g and a reasonably controlled cone break up and a flat-enough response to work with:

Beyma_10G40_(Frequency_response_+_Distortion).png


Its distortion seems to rise quite fast below 100 Hz, though:

War of the Monster Midbasses July 21 2019 01.png

The Faital i.e. goes quite a bit later:

faital_10pr320_thd.jpg


At my listening volumes, I can avoid a HP filter. They introduce a lot of additional group delay. If I will use this drivers in another role as High-End PA of for gallery/show room installations, I will do it if needed. As you already remarked, it is possible every time and a dedicated profile for high SPL use is a feasible option.

I followed you advice and created QB3 alignments with the four drivers at question. Here is the results, what do they tell me in combination with the above equalization results?

qb3.JPG
QB3 alignments in numbers:

phl audio 3411 (black)
6.5 liters
fb = 78

faital 10pr320 (blue)
15.4 liters
fb = 64

beyma 10g40 (green)
19 liters
fb = 57

sba wo24p (red)
71 liters
fb = 25
 
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Have we actually ever had any advances in the question whether or not Mms is relevant for mid range reproduction? In 2014, Earl wrote:
I can agree that high BL in a woofer is desirable - actually BL/Re. There actually is science there. But I fail to see any science that says that lower cone mass is a benefit. "Micro-dynamics"? Really? Are we going back to talking about the mystical/magical aspects of loudspeakers?
He also suggested high BL or BL/Re, but in the question of Mms, there was no settlement or conclusion.
 
Have we actually ever had any advances in the question whether or not Mms is relevant for mid range reproduction?

He also suggested high BL or BL/Re, but in the question of Mms, there was no settlement or conclusion.

No advances, this is one of those topics that engenders opinions rather than facts. The below links make sense to me.

Woofer Speed 1 WOOFER SPEED - PDF Free Download

Bl/Mms = Nonsense

Bl^2/Re relative to MMS makes more sense as it considers the current.
 
Just for fun then, let's create a dimensionless number, the Mid Range Factor (MRF). MRF = Mms/(Bl^2/Re). The lower, the better. Playing with some drivers:

PHL audio 3411
BL = 20.2
Re = 5,6 (+-0.6, they append)
Mms = 58
MRF for Re 5,6 = 0,796
MRF for Re 6,2 = 0,881
MRF for Re 5 = 0,710

18sound 10NW650
Bl = 14
Re = 5
Mms = 34
MRF = 0,867

10PR320
13,5
5,3
35
MRF = 1,017

Beyma 10G40
Bl = 17
Re = 6,2
Mms = 52g
MRF = 1,115

10WR300
Bl = 14,2
Re = 6
Mms = 39g
MRF = 1,16

Kappalite 3012LF
Bl = 14,27
Re = 3,89
Mms = 72
MRF = 1,375

12PR320
Bl = 13,5
Re = 5,3
Mms = 51,4
MRF = 1,494

Deltalite II 2512
Bl = 10,69
Re = 5,17
Mms = 37
MRF = 1,63

An observation: Some builders of large two-way speakers reported that Deltalite II 2512 was sounding better than Kappalite 3012LF, yet, the factor would contradict such judgement. I included them to check this, but the factor fails to verify this subjective impression.
 
Sheeple, could i offer a different point of view on the woofer choice matter.

I saw Peerless HDS you wanted to use but gave up because TS parameter issue. I've done few simulations myself so here it goes.

This is Peerless HDS 8" vs B&C 10PLB76. Here is sim in 30 liter cabinet for Peerless and 20 liter cabinet for B&C.

0.png

Looks dreadfull, right. Now, i applied 2 substractive filters shown on the pic so no extra excursion wasted. Not perfect simu but it will do for me to prove a point.

1.png

Mind you, this is transfer function magnitude. Now let us see how SPL vs applied voltage of 2.83V looks like in 2pi conditions at 1m for both.

2.png

Well, not bad at all. They are few dB apart. B&C is so much more sensitive than Peerless that you can equalize it and still remain competitive.

Let us crank up the volume to 28.3V just to see what happens with amplifier apparent load.

3.png

Look how much more VA Peerless needs in high bass and midrange than B&C. Let us see what happens with excursion at 28.3V since there is only 0.5mm difference in Xmax between the two.

4.png

I think that we can safely conclude that Peerless HDS is dead while B&C 10PLB76 is in linear excursion down to 35Hz.

Maybe quest for better midwoofer isn't necessary. Maybe by doing simulations like these you realize that you already have it. Just use lowest Mms ones from the bunch.

cheers,
Mladen
 
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Sheeple, could i offer a different point of view on the woofer choice matter.
I never thought about it that way and there is a simple reason: WinISD. It lets you fake a high shelf with a LT filter, but that screws up everything else, excursion, level etc. Thank you for this contribution, maybe I will just reduce efficiency for home listening.

Maybe quest for better midwoofer isn't necessary. Maybe by doing simulations like these you realize that you already have it. Just use lowest Mms ones from the bunch.
You still seem to stand by your point, that Mms in itself is the physical quantity which has to be controlled. I saw you were asserting this back in 2014, too. I seemingly have to pick between camps? This is a little bit frustrating. :eek: (I was leaning towards the PHL lately, 58g Mms)
 
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I never thought about it that way and there is a simple reason: WinISD. It lets you fake a high shelf with a LT filter, but that screws up everything else, excursion, level etc. Thank you for this contribution, maybe I will just reduce efficiency for home listening.

Which shouldn't be a problem since you're going active. Reducing efficiency of pro woofers gets you in the ballpark with home woofers regarding SPL/1W/1m but with enormous power handling. Woofers you've chosen are for PRO use and are made to play at 120dB+. Shaving even 10dB out of that figure still leaves you with a beast louder than any home 10" woofer.

....
You still seem to stand by your point, that Mms in itself is the physical quantity which has to be controlled. I saw you were asserting this back in 2014, too. I seemingly have to pick between camps? This is a little bit frustrating. :eek: (I was leaning towards the PHL lately, 58g Mms)

Nothing wrong with that. I thought that you are leaning toward lower Mms woofers. There are lots of two way speakers that use high Mms woofers and higher crossover frequency. Subjectively, i just happen not to enjoy sound of those in conditions i listened them in. That is where preference comes into play.

PHL's are great midwoofers and you go ahead and use them. Make test cabinets (as you've done with current project) and have a listen. If you don't like them, you can always sell them and try some other. Make a journey out of it :)
 
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That's can of worms opening but here it goes. In my experience, lower Mms midwoofers (if other parameters are satisfactory) sounded livelier in midrange. Higher Mms woofers could do it too but needed more watts but, since i listen from 2.5-3m, when i push enough watts in them to sound subjectively livelier, it is too loud for me to listen. In a larger room from larger distance it might not have been a problem. My experience is with Deltalite II 2512, Beyma 12LW30, Beyma SM115/K, Sonido SCW300 and B&C 15TBX100. I'm playing with 12pr320 and my friend uses Deltalite II 2515 and Mabats ST260 and CE360 so we'll see how it goes.
 
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lower Mms midwoofers (if other parameters are satisfactory) sounded livelier in midrange.
Two things to consider out of this that is relevant.

"If all other parameters are satisfactory", this is why I think concentrating solely on the weight of the cone is a bad idea.

What is the frequency response, the impedance response, the Sd, the xmax, Le, the motor design, CSD etc. etc.

"Sounded Livelier" descriptions of sound are notoriously difficult to interpret and this is not meant as any criticism, but what happens if Zvu's livelier is not an attribute you prefer?

If you have not tried a lot of different things yourself or have found a person in whose opinion of sound quality you seem to share significant agreement how are you to know whose opinion to trust?
 
The Beyma 10G40 has actually a bit lower Mms at 52g and a reasonably controlled cone break up and a flat-enough response to work with:

...

Its distortion seems to rise quite fast below 100 Hz, though:
fb = 25


The THD % comparison graph is from the 10" mid-bass thread by member OscarS. The 10G40 sticks out as being the worst, but I remember he said that might have been rattling inside his test box, so it's possibly a measurement error. (I haven't gone back now to find the post again.)


By eyeballing the FR of the 10G40 in the datasheet it may look fine, I've traced it in Vituix, then it looks much worse, but then again eyeballing the FR and comparing it to other woofers in Oscar's thread I think it actually looked one of the best to me. So I wonder.
 
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I think that we can safely conclude that Peerless HDS is dead while B&C 10PLB76 is in linear excursion down to 35Hz.

To what frequency do you guys usually keep the woofer within linear excursion (xmax)? This morning, I made some SPL tests at my LP (2.7 meters from the speakers). I measured with Z weighting and peaks would reach 95 to 98 dB, while maximum was usually around 80 dB only. Depending on music, naturally.
Miles Davis 'So What' was very loud at this levels, while for equivalent loudness impression, Drum & Bass would need higher levels, as there is more information in the bass spectrum. When mid and high frequncies matched instrumental music, the meter would easily exceed the mentioned peak levels. Same goes for amplified music with bass guitar, like Fugazi (i.e. 'Closed Caption' on Instrument Soundtrack).

But RTA says below bass, <80 Hz, there is much less energy. For the aforementioned Fugazi song, i.e. the sub bass is 20 dB lower than bass. This got me thinking to which frequency I should think about keeping within xmax, and where xdam should be the limit. Until now, I always used 20 Hz as my lower limit, but to keep within peaks to 20 Hz, a high pass that introduces group delay becomes necessary.
 
It is very hard to know what values to use for xmax as many manufacturers specify them differently. xdamage xmech should never be a target.

Klippel results for drivers are good because they show how the motor force, compliance of suspension and inductance change with coil position. Many drivers are quite nonlinear well below their rated xmax often due to the suspension used. B&C and 18Sound in particular have some incredibly linear drivers.

This is from B&C's FAQ on their website

"Thiele – Small parameters have become the universal language for describing loudspeaker behavior in the small signal domain. Nevertheless, they comment little on the working limits of loudspeakers in the large signal regime.

These limits are customarily indicated by Xmax, the maximum linear excursion. This value is typically measured according to the AES2-1984 standard, corresponding to a maximum of 10% total harmonic distortion (THD) with a sinusoidal signal (though most manufacturers, including B&C, now typically provide data for Linear Mathematical Xmax, not measured Xmax). Recent research shows that this method can yield ambiguous results, and even different numerical values for the same loudspeaker. The main limit of this measurement is that it looks at the output signal instead of the physical features of the driver itself. On the contrary, the most up-to-date instruments for distortion analysis can measure the variations in loudspeaker parameters when they are fed with high-level signals. In this way, an excursion limit can be fixed, beyond which the parameter’s variation becomes excessive.

The “X var” value reported in our data (generally after the traditional “Xmax” value) is measured this way. Beyond this excursion limit, the magnetic field seen by the voice coil, or the total suspension compliance, or both, drops to less than 50% of their small signal value, producing high distortion levels, strong variations from small signal behavior and power compression. The new technique yields different results from the standard measurement based on THD. B&C Speakers believes that this added information gives a more accurate and reliable description on loudspeakers behavior in actual operating conditions."


Jeff Bagby's Woofer Designer program is still a really good way to look at different drivers if you have a version of excel that it works with. It is still on Charlie Laub's site.

That has a section for Linkwitz Transform and a lot of other basic EQ functions that can be switched in and out to see the effect they have on excursion etc. It requires input of the parameters but that really only takes a minute or so and can then be saved in the database for later recall.

Lots of music has no content below 30Hz and I had a 30Hz switch on my old Orion crossover, on a lot of music I could not tell the difference between positions.

More and more music is being made with very low frequency content whether it is intentional or by accident using monitors that don't allow it to be heard. Now I have speakers that can reproduce it I like it and would not want to be without it.

Because of this vented systems that you intend to play loud often need a highpass to prevent this very low frequency content from causing wild excursions.

As far as group delay is concerned you might want to compare it to this set of graphs to determine if the group delay stands much chance of being audible.

https://research.aalto.fi/en/publications/audibility-of-loudspeaker-group-delay-characteristics
 

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Thank you for the detailed response. I will just try it out, as I do have the impression that I have never hit any high excursions in my home listening, yet. Admittedly, I cannot see what the voice coil does. And while I strive for performance, in the case I'd use the speakers in another setting, I can still change DSP for this role.
I know the graph that you showed, and have always been wondering that it is in conflict with some other rules, like the max. half-cycle even below 100 Hz. But it does seem easy to conform to the limits which graph b imply: Most pro woofers have no problems in the 300-1000k area, even with a vented-assisted enclosure.
 
I like to know what is Xmech/Xlim/Xdamage in a woofer i'm using. It is virtually impossible to keep the cone movement in linear mode all the time down to 20Hz and some music and movies have sudden impulses very low in frequency and high in level. I can simulate in Winisd what is maximum volume achiavable without any damage to the woofer.

That baing said, i'd make hipass filter at 20Hz a mandatory option for all amplifiers because of modern music and movies production. Ironically, amplifiers of 70's up to 90's had that in form of subsonic filter (used when listening vinyl records). I'm making passive crossovers in loudspeakers but would always dile in woofer protection in software since i'm using computer as a source 100% of time.
 
So they included the two graphs on TLHP as a reaction to my email inquiry. The full dataset is two pages, one additional page to the published. What they seemingly do not want to give away to the general public is three nonlinear Klippel measurements. Bl to X, Kms to X and Le to X. I think I am not supposed to share the document itself, but if I understand these graphs correctly, with higher excursion Bl is less than published number and Kms is higher, perfectly symmetrical in X plus/minus directions. So, looks well controlled and numbers seem to be good for excursion levels we are interested in. Actually this seemingly contradicts Zvu’s observation, as Bl is higher at lower excursion.
 
I never observed Klippel measurements for midwoofers i didn't like the sound of. If manufacturers provided those regularly in their datasheets, maybe we could draw much more educated guesses than conclusions that might be wrong as much as they might be right.