To reveal my plans....
12MU is my favorite midrange, it has good balance of all parameters and measuremrnts and sound excellent. So I am tepmted to add 12inch woofer and make old school looking 3way. I know 12MU can manage ~400hz lr2 without sounding thin but I would not try to cross it over lower.
I would like to have system sensitivity above 87db, and reasonable extension -6db at 30hz.
12MU is my favorite midrange, it has good balance of all parameters and measuremrnts and sound excellent. So I am tepmted to add 12inch woofer and make old school looking 3way. I know 12MU can manage ~400hz lr2 without sounding thin but I would not try to cross it over lower.
I would like to have system sensitivity above 87db, and reasonable extension -6db at 30hz.
tktran: yes, correct. For the rough, out of head, calculations I use -6dB at Fc + the slope per octave. With 400Hz Fc the slope does not have full -12dB per octave yet, so the response is down by -14dB. I checked in Vituix.
I would like to go with 50-60l BR.
I would like to go with 50-60l BR.
Unfortunately I have no experience with selecting a 12" woofer for acoustic LR2 around 400Hz... mainly because my midrange only had about 1mm excursion. The 12MU4731T00 is a unique baby with a flat and smooth response from 100Hz to beyond 4KHz, high 90dB/2.83V sensitivity but also plenty of excursion... I was wondering when someone would try this! (apart from B&O).
So I look onwards with much enthusiasm as you look for this unicorn...
@mbrennwa , do you perhaps has some experience? I recall you went through a shortlist when you selected a 12" woofer for BR when you designed the OSMC...
So I look onwards with much enthusiasm as you look for this unicorn...
@mbrennwa , do you perhaps has some experience? I recall you went through a shortlist when you selected a 12" woofer for BR when you designed the OSMC...
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Curiously a driver which meets this requirements is the W22NY003 in 50-60l BR.
It is the best driver from SEAS to my ears. The paper cone of this driver is light and the motor is good. Only criticism is the bass "definition" but needs more tests and my reference is open baffle with a lot of surface. For me it is a highly recommended good sounding driver.
The sb34nrxl and the 12rs430 can be use but not sure you have the same midrange quality.
The SB34NRXL can be used at a 400hz 2nd order LP, but the critical thing is to mind that 700hz kink in the curve, as it may actually not be a problem in practice, using an offset sloped LP (early onset of amplitude drop-off in the filter slope). If the midrange driver can deal with a little more low mid energy it receives from a slightly early rise in amplitude, but the same -6 dB point as the woofer. It will be close regarding what the mid can handle if the volume is pushed.
If that could help, I made open baffles with 2x12" + 5"+1" 500Hz LR2. Two problems I notice :
1. A clean midrange, some 12" has a colored sound above 200Hz, not very clear mid, demodulating ring could help ?
2. 2KHz breakup could ruin the treble. It needs to be suppress.
These configurations sound very good when carefully done in all area bass mid treble.
Here with the SLS315 85dB F3 40Hz
With the 12OB150 87dB F3 40Hz
1. A clean midrange, some 12" has a colored sound above 200Hz, not very clear mid, demodulating ring could help ?
2. 2KHz breakup could ruin the treble. It needs to be suppress.
These configurations sound very good when carefully done in all area bass mid treble.
Here with the SLS315 85dB F3 40Hz
With the 12OB150 87dB F3 40Hz
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@PKAudio ,
Had the same 12 +5+1 thinking, but found many woofer are lacking spl in the low end but we need it mainnly here as subwoofer. The room gain seems never high enough to help them below 80/100 hz where they fall fast (SB34RNX-L ; Faital 12PR320, ....). Some complained with the Zaph sealed 12.3 with the driver from SB, a little weak low end... or maybe a not so clean midbass ???
This means imo a clean 5" in the low end for a cut off at 200 hz max where the subwoofer drivers beginns no to shine.
So I thougth more about driver like the SB34SW 6 ohms. 89 dB relativly flat plateau when you sim it, not monstruous cab with 0.6 to 0.7 Qts.
I plan this with one or two 8 homs (MTM in standalone stacked enclosurre) with the NE149W-08 (still sourcable in Europe at Soundimports) and Seas 22/TAF (if not MT conf) ! cut off in the 150/250 hz (150 hz unlickilly a little too much challenging for the thd).
The 12" Faital you linked (TG launched a new Faital 3WC with it) is temting too. Or two 10" in cancelation (woven SCANSpeaK, but efficienty ?)
I lost 2 years in this project for some reasons, and a little more foccussed on a DIY DAC lately.
cheers
Had the same 12 +5+1 thinking, but found many woofer are lacking spl in the low end but we need it mainnly here as subwoofer. The room gain seems never high enough to help them below 80/100 hz where they fall fast (SB34RNX-L ; Faital 12PR320, ....). Some complained with the Zaph sealed 12.3 with the driver from SB, a little weak low end... or maybe a not so clean midbass ???
This means imo a clean 5" in the low end for a cut off at 200 hz max where the subwoofer drivers beginns no to shine.
So I thougth more about driver like the SB34SW 6 ohms. 89 dB relativly flat plateau when you sim it, not monstruous cab with 0.6 to 0.7 Qts.
I plan this with one or two 8 homs (MTM in standalone stacked enclosurre) with the NE149W-08 (still sourcable in Europe at Soundimports) and Seas 22/TAF (if not MT conf) ! cut off in the 150/250 hz (150 hz unlickilly a little too much challenging for the thd).
The 12" Faital you linked (TG launched a new Faital 3WC with it) is temting too. Or two 10" in cancelation (woven SCANSpeaK, but efficienty ?)
I lost 2 years in this project for some reasons, and a little more foccussed on a DIY DAC lately.
cheers
I found the same thing, it is difficult to reproduce below 40Hz. And the second thing all woofers don't have the same definition in the bass area. Some of them can reproduce better nuance of bass. I wonder if the suspension is better and more linear, given a stable Fs(X). Some manufacturers like Purifi, Kartesian, Sica (on some models) claim a large stable Kms(X) .
It certainly does, whatever the size However size matters (front volume), perhaps even more from the third octave till the mid-bass. But it is an opinion than a fact. And it is a problem as most subwoofer made driver are not so good there (>100 Hz ???)
Also less Sd, more heat in the voice coil and more surface mode as for the same spl there is more voive coil deplacement... I surmise adaptation to air impedance to be easier when low deplacement while more surface to air is maybe counterintuitive.
well we know it from a long time the motor matters, see TAD 1601 ! ... Or woofer >60 Hz (SB34 RNX-L) and distributed bass < 60 hz perhaps ! (more expensive). Too bad Davis Acoustic are too much expensive with their 15/16 woven drivers ! (well big Vas, good but needs area for the cab, also there the SB Acoustics 15" is tempting). But I do thing 12" + 5" + treble is ok for most of us. (or 10" push-push + 5" + treble). Just my basic opionion.
Also less Sd, more heat in the voice coil and more surface mode as for the same spl there is more voive coil deplacement... I surmise adaptation to air impedance to be easier when low deplacement while more surface to air is maybe counterintuitive.
well we know it from a long time the motor matters, see TAD 1601 ! ... Or woofer >60 Hz (SB34 RNX-L) and distributed bass < 60 hz perhaps ! (more expensive). Too bad Davis Acoustic are too much expensive with their 15/16 woven drivers ! (well big Vas, good but needs area for the cab, also there the SB Acoustics 15" is tempting). But I do thing 12" + 5" + treble is ok for most of us. (or 10" push-push + 5" + treble). Just my basic opionion.
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Edit: as PKAudio is knowing, the SCANSPEAK subjectivly sound very good there, but too much expensive for my wallet. Kartesian too. However the 4" Kartesian medium is attractive but I do wonder about his low limit despite being a Kartesian, it has already much lower efficienty than the datasheet claims and it is rigth in the baffle step area !
Thanks for the responses, I will give it yet some thinking...., there is always fallback scenario to go with 5" midrange and prototype cabinets will be made to allow that. Cabinets will also allow to mount SB34NRXL or other 2-3 alternative woofers. The volume will be 60l, which seem to be quite sweetspot for 32W, NRXL,....
Careful filtering, response linearization and breakup suppression are the must, and even before that I will need to measure FR especially for woofer with longer window, to really see what is going on with the woofer response. 32W T11 will not be as linear as it could seem, same as T00 which I already know very well.
12MU can do ~105dB and that is a lot. It will not keep up with 12inch woofer, but it is not needed.
Jerome, I agree with the part about the definition in the bass region. There were woofers that did not sound as I would expect, no matter what I tried. They seemed to sound almost ok, but once I heard another woofer the difference was clear. Just to mention few, Scan Speak woofers, Peerless NE, even U22 have very good definition.
I am getting to the conclusion I will just have to try and see and listen to the system to really know. As always.
Careful filtering, response linearization and breakup suppression are the must, and even before that I will need to measure FR especially for woofer with longer window, to really see what is going on with the woofer response. 32W T11 will not be as linear as it could seem, same as T00 which I already know very well.
12MU can do ~105dB and that is a lot. It will not keep up with 12inch woofer, but it is not needed.
Jerome, I agree with the part about the definition in the bass region. There were woofers that did not sound as I would expect, no matter what I tried. They seemed to sound almost ok, but once I heard another woofer the difference was clear. Just to mention few, Scan Speak woofers, Peerless NE, even U22 have very good definition.
I am getting to the conclusion I will just have to try and see and listen to the system to really know. As always.
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The RNX- L will lack some low end imo but has the good above 150/200 he sound ! See it as a midbass driver. Or at least it could interesting to see how it reacts in the lows helped by a passive ? But SB made no passive for it specificly. Ceratinly the new 12 Faital you talked is a better bet...
That is tradeoff I am ok with, I look for driver capable of good lower midrange without the need of ~200Hz crossover or lower. System sensitivity >87dB, 1 woofer. Extension -6dB at 30Hz, with slower gradual rolloff is what I am looking for. Larger cabinet volume would push the -6dB point lower but I do not want that, I want to keep cabinet size reasonable.
so rnx-L has the good sound in the midbass area, but imo since you beginn to sim it, you will need more than 60L but boosting or group delay trade offs, imho ! Active is another story of course.
-6dB at 40 Hz, you shouldn't be far with the 12PR320 ; 75 L, f3 55 hz. Clean mid bass, plenty of spl to manage the baffle step and cut off as high as you want if the 5" is not clean enough in the lows. Of course with your low efficienty requirement,the rnx-l is certainly the sweet spot. Ask @profiguy who knows it well
-6dB at 40 Hz, you shouldn't be far with the 12PR320 ; 75 L, f3 55 hz. Clean mid bass, plenty of spl to manage the baffle step and cut off as high as you want if the 5" is not clean enough in the lows. Of course with your low efficienty requirement,the rnx-l is certainly the sweet spot. Ask @profiguy who knows it well
Unfortunately Yes, the problem is we don't have Klippel measurements, we miss data to have a good evaluation of the driver unit. TS data and distortion are not enough. This is why I like voice coil tests :
https://audioxpress.com/article/test-bench-scan-speak-32w-4878t00-subwoofer
do not forget the efficenty given in the datasheets are 2PI when we will experience a loss there as it is 4Pi territory : AKA do not stand by room gain to help a weak 2Pi datasheets in the lows (high efficienty drivers or woofers that are not subwoofers) 🙂
Or design speakesto be next the front wall to stay near 2Pi. Imo what we measure in room for the bass is the room itself, so how to model it, say under 100 Hz ?
Room wizar room measurement : but with what signal medium ?
Or design speakesto be next the front wall to stay near 2Pi. Imo what we measure in room for the bass is the room itself, so how to model it, say under 100 Hz ?
Room wizar room measurement : but with what signal medium ?
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1. If you think that you will benefit from a Klippel to determine Le(x), Kms(x), BL(x) then keep an eye out for Dayton Audio’s upcoming DATS-LA.
2. Whilst waiting and determining the woofer, have you considered modelling your cabinet with idealised 12” woofer? For instance, the effect of woofer positioning on baffle, effect of floor bounce, the effect of acoustic LR2 400Hz crossover on polar responses. Sometimes I get a little excited by new drivers but new processes and methodology can lead to better results, too.
2. Whilst waiting and determining the woofer, have you considered modelling your cabinet with idealised 12” woofer? For instance, the effect of woofer positioning on baffle, effect of floor bounce, the effect of acoustic LR2 400Hz crossover on polar responses. Sometimes I get a little excited by new drivers but new processes and methodology can lead to better results, too.