My wife is quite mad at anyone who recommended the Discovery 15W/4434G00 🤬 Just kidding 🙂. I have a pair coming from Madisound, if they are here by this weekend I'll get them measured. I have five of the 5-inch drivers that have been discussed. I also have SB26ADC, SB26STAC, and two others that I'll measure on the wide baffle.
I know that you have already decided on 12" woofer and i understand why.
At risk of you guys throw tomatoes at me - would you reconsider 10" ?
I don't remember (haven't read the whole thread) if anybody mentioned SBacoustics SB26SFCL38-4. While it is a 10" only, i think it has some advantages over SLS 12.
-It is easily obtainable in Europe, USA and AU
-It is adapted for closed cabinet
-It costs 70€ / 86$
-It price will probably stay unaffected by EU/USA/CHN trade war that is about to happen.
-There are probably more pro's but i am quite lazy. I threw you the idea, you guys think about it - i'll be carrying my umbrella everywhere for a couple of days, thank you very much.
At risk of you guys throw tomatoes at me - would you reconsider 10" ?
I don't remember (haven't read the whole thread) if anybody mentioned SBacoustics SB26SFCL38-4. While it is a 10" only, i think it has some advantages over SLS 12.
-It is easily obtainable in Europe, USA and AU
-It is adapted for closed cabinet
-It costs 70€ / 86$
-It price will probably stay unaffected by EU/USA/CHN trade war that is about to happen.
-There are probably more pro's but i am quite lazy. I threw you the idea, you guys think about it - i'll be carrying my umbrella everywhere for a couple of days, thank you very much.
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I think the 10/4/1 combo is very attractive. Smaller boxes, still great performers, and can sustain the output. Eminence Kappa Pro-10LF, Lavoce-WSN041.00-4, SB26STAC, or maybe a ribbon tweeter? The GRS or similar would keep up with sensitivity requirements.
Is the Peerless SLS 830669 12" not easily obtainable in Europe and AU?
Is the Peerless SLS 830669 10" any different?
These are also adapted for closed cabinets, but if not easily available, then that is definitely something we need to keep in mind.
I'd be willing to model the SB26SFC (or someone else can if they have time).
Oh yeah, and...
Peerless is fine and obtainable - for now. Peerless is also known for changing their policy of transducer sale regarding number of units and availability to DIY-ers (anyone saw Peerless corundum dome tweeter lately - 32mm measured great and was sold at insanely good price). They can also discontinue models for no particular reason. While SBacoustics also does that, they substitute it with similar unit/s. They just seem to me as more reliable company.
I mean, i have no horse in this race and if i can't help, i definitely don't want to make things harder. I like Peerless SLS12 also.
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It won't matter whatever happens to chosen driver future availability.
The coalition of the willing could design a new one, a better one,
whatever you desire philosophy.
The coalition of the willing could design a new one, a better one,
whatever you desire philosophy.
Some comparisons of the Peerless SLS 12" 830669-8 ($65 / €100) and the SB Acoustics 10" SB26SFCL38-8 ($86 / €73). I did these in WinISD because it is easier to show direct comparisons. Bottom line...
RED -- SLS 830669 in 2.3cf (65L)(Q=1.0) F3/6/10 = 45/38/30Hz
BLUE -- SBA26SFCL in 2.15cf (61L)(Q=0.85) F3/6/10 = 41/33/26
RED -- SLS 830669 Rated power of 100W ...cone excursion less than xmax
BLUE -- SBA26SFCL at 50W to reach xmax
Total 2pi SPL at rated power/xmax SLS 12 is 5dB higher
If we limit the SLS 12" (RED) to only play at 104dB, as loud as the SBA 10" at 50W and xmax (BLUE), the SLS 12" would require 30W and cone excursion about 40% of xmax.
- The 10" SBA models better in a cabinet size that fits our format. The 12" SLS has a Q of 1.0 in 65L while the SB26 has a Q of 0.85 in 61L. I don't know what people's opinions are regarding a Q of 1.0 but I assume many would prefer 0.90 or below if we could, and with the 12" SLS we simply can't make the cabinet as big as would be required (135L for a Q of 0.85). (We can discuss aperiodic later though 😉 )
- The 12" SLS can take more power and move more air and go louder. The SLS only comes in an 8-ohm version and I simulated the SBA 10" in the 8-ohm version. The SBA does come in a 4-ohm version, so that is something that could be looked into. The SBA 10" max SPL is at xmax with 50W. The SLS 12" max SPL is at max power handling of 100W which only drives it about 2/3 of the way to xmax.
RED -- SLS 830669 in 2.3cf (65L)(Q=1.0) F3/6/10 = 45/38/30Hz
BLUE -- SBA26SFCL in 2.15cf (61L)(Q=0.85) F3/6/10 = 41/33/26
RED -- SLS 830669 Rated power of 100W ...cone excursion less than xmax
BLUE -- SBA26SFCL at 50W to reach xmax
Total 2pi SPL at rated power/xmax SLS 12 is 5dB higher
If we limit the SLS 12" (RED) to only play at 104dB, as loud as the SBA 10" at 50W and xmax (BLUE), the SLS 12" would require 30W and cone excursion about 40% of xmax.
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Here's the VituixCAD2 simulation for Tymphany 830668 (10" SLS) in 1cu ft, with 21.5V volt applied to reach max SPL:
Here's an actual measurement of the 830668 in 1 cu ft, with fiberglass stuffing. 21.5V absoluted calibrated voltage. B&K mic at 2cm for a 2pi measurement- SPL shown for ~1m 2pi SPL:
I do not have experience with the SB26SFCL38-8. I share @Zvu's concern for future availability. Few would WANT to re-measure and re-do a passive crossover due to supply issues...
Here's an actual measurement of the 830668 in 1 cu ft, with fiberglass stuffing. 21.5V absoluted calibrated voltage. B&K mic at 2cm for a 2pi measurement- SPL shown for ~1m 2pi SPL:
I do not have experience with the SB26SFCL38-8. I share @Zvu's concern for future availability. Few would WANT to re-measure and re-do a passive crossover due to supply issues...
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My guess is that comparing the 12" SLS 830669 to the 10" SLS 830668 is very much like comparing it to the SB26SFCL.
The 12" SLS really should be in a larger cabinet than we can provide so either of the 10" drivers will have a Q of closer to 0.75 to 0.85. Using the old (2017) data sheet for the 12" SLS it appeared 65L would give us a Q of 0.90 but the new (2021) TS parameters on the Peerless website change that to Q = 1.0.
The two tradeoffs I see are both subjective - although the first is at least based on hard data:
Peerless 830669 $69 / €100
Peerless 830668 $54 / €90
SBA SB26SFCL38-8 $86 / €73
Just an illustrative example (i.e., midrange and tweeter have not been decided yet):
Peerless 830669; Scanspeak 15W/4434G00; SB26ADC x 2 = $405 / €435
Peerless 830668; Scanspeak 15W/4434G00; SB26ADC x 2 = $375 / €424
SB26SFCL38-8; Scanspeak 15W/4434G00; SB26ADC x 2 = $440 / €390
The 12" SLS really should be in a larger cabinet than we can provide so either of the 10" drivers will have a Q of closer to 0.75 to 0.85. Using the old (2017) data sheet for the 12" SLS it appeared 65L would give us a Q of 0.90 but the new (2021) TS parameters on the Peerless website change that to Q = 1.0.
The two tradeoffs I see are both subjective - although the first is at least based on hard data:
- Do we prefer the lower Q rolloff of of a 10" driver vs the 12" driver at the expense of ~5dB max output (and maybe some audible distortion at peak SPL)?
- Do we prefer the Classic "Look" of the larger 12" driver? (Accepting that those Classic speakers sometimes had 10" or 8" drivers too)
Peerless 830669 $69 / €100
Peerless 830668 $54 / €90
SBA SB26SFCL38-8 $86 / €73
Just an illustrative example (i.e., midrange and tweeter have not been decided yet):
Peerless 830669; Scanspeak 15W/4434G00; SB26ADC x 2 = $405 / €435
Peerless 830668; Scanspeak 15W/4434G00; SB26ADC x 2 = $375 / €424
SB26SFCL38-8; Scanspeak 15W/4434G00; SB26ADC x 2 = $440 / €390
If you're going for the 15W/4434G00 as a pure midrange, why not choose the 4424G00 - shorter voice coil, higher sensitivity...
In the modern era, I pay less attention to the theoretical Qtc. Remember that it is a 2pi response.
The baffle diffraction loss determines the anechoic response (4pi). And then of course the room ultimately determines the low end response.
How important is the Qtc in a sealed box alignment? @DcibeL @Juhazi ?
The baffle diffraction loss determines the anechoic response (4pi). And then of course the room ultimately determines the low end response.
How important is the Qtc in a sealed box alignment? @DcibeL @Juhazi ?
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Joined 2003
in a world where PEQ is commonplace, not as important as you might think. The reality is that if you place 2 difference drivers of the same size in the same box, and EQ for the same response, the cone movement will be the same (excursion vs frequency), the real difference will be in the amount of power required to make it happen, which will vary based on the driver sensitivity and EQ provided.
In theory, a Qtc=1 provides a gain of about 1 dB an octave above F3. In reality, it might end up being more than that after the woofer low pass crossover is included. I stumbled into this effect here: passive filter gain
I have since confirmed that this is not unique to the woofer/box/crossover I was using. Nearly any woofer will generate a 1.5 - 2.5 dB gain in the bass region when combined with a 2nd, 3rd, or 4th order low pass passive filter in the 200 - 400 Hz range. The way to avoid it is a low frequency impedance compensation network, which can be expensive and is rarely done.
So we will probably have a 2 dB hump from ~ 60 - 120 Hz just from the electrical circuit. Do we really need/want an additional 1 dB of gain in the same region because the Qtc = 1.0 ?
j.
This is kind of my question...I think the answer to your question is, "no," we do not WANT a 2dB hump or a Qtc = 1.0. But do we accept it as part of the tradeoff? The tradeoff is +5dB max SPL and lower distortion from the 12" woofer OR go to a 10" driver, where we can easily get a more desirable Q but lose 5dB of max SPL and have to reach xmax to get it.
A couple of things make me feel okay about the higher Q for now: it could be fine as-is; it can be fixed with PEQ; it may be smaller if we cross close to 400Hz which probably works; it might be able to be fixed going aperiodic; we don't have the driver yet (since it is out of stock in the US) but the OLD data sheet implied a Q=0.9 rather than Q=1.0 in the same cabinet. (I don't have a lot of faith in this last option as data sheets never seem to be wrong in the way that makes things better for us 😂)
Now I see why the world moved towards electronically controlled crossovers.
The passive must rely on “one ring to rule them all” mythology.
Since 1978, you just dial in whatever Q you want, whatever cut or boost you want.
Tune the actual in-room response, rather than the theoretical Q, or imaginary anechoic response.
Keep the additional +5dB dynamic range and lower distortion advantage, and still have the Q (or box size) you want.
After all, you have a lot more than 8 or 30W to play with…
My EE professor once told me that the reason that smartphones were about to enter the market (for those old enough to have “dumb” phones) was enabled only because of the development of the lithium polymer battery.
The passive must rely on “one ring to rule them all” mythology.
Since 1978, you just dial in whatever Q you want, whatever cut or boost you want.
Tune the actual in-room response, rather than the theoretical Q, or imaginary anechoic response.
Keep the additional +5dB dynamic range and lower distortion advantage, and still have the Q (or box size) you want.
After all, you have a lot more than 8 or 30W to play with…
My EE professor once told me that the reason that smartphones were about to enter the market (for those old enough to have “dumb” phones) was enabled only because of the development of the lithium polymer battery.
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