Any problems with this WinISD model/design?

[NathanC]

Hello everyone! I'm hoping I can get some help from some of the experienced people here. I've modeled a few different boxes for the SQL 15 driver from stereo integrity. The graphs/outputs I'm able to get seem great but based on some of the other threads I've seen on this forum for this driver, I'm wondering if I've done something wrong.

I've just about settled on a 4.25^3ft boc with a port tuned to ~17hz. I'm unsure how close to xmax I should really allow the drivers to get but model shows spl that I will probably never even want to hit. Usually will be using half this power at most just to be safe and it should still be plenty loud if my understanding is correct. I wanted to try to keep the response as flat as possible as low as possible because it's going in a very large room that probably won't provide much gain.

I have a peq filter at 20hz +4db q=1 with a buttersworth 4th order at 14hz to keep xmax under control below tuning and still keep as much output as possible. The group delay is a little concerning, but from what I've read is mostly a non issue at the frequencies that it's so high at. Right now I have a Bheringer 3000D in mind for the amp. I'll get the 4ohm DVC version of the driver an wire in parallel to 2ohms for the amp. Limit to 27v ~500w(may not make a lot of sense but will give me plenty of headroom). The PEQ may be a bad idea but I'm unsure.

Suppposedly F3 will be ~18hz F6 ~16hz F12 ~13.5hz. Peak excursion right at 26mm at 13 and 25hz. Xmax for the driver is 28.4 so Maybe that's pushing it, I just don't know but also real world will almost never be driving it at these levels. Also db is at 2.2 meters. Air velocity right at 25m/s. That is the part that is probably wrong but I can figure that part out a little better when I actually make a finalized box design once I know I'm okay to move forward.

I originally was going to do a "VTF" dual port design because I thought the idea sounded cool but I realized how little I would ever change the tuning plus how impractical it would be. I can send the modeling I got for those as well if this one is completely wrong, but if that's the case those probably are too.

Thank you to anyone who can take the time to help educate me. I really appreciate it!!

 

[TLS Guy]

Hello everyone! I'm hoping I can get some help from some of the experienced people here. I've modeled a few different boxes for the SQL 15 driver from stereo integrity. The graphs/outputs I'm able to get seem great but based on some of the other threads I've seen on this forum for this driver, I'm wondering if I've done something wrong.

I've just about settled on a 4.25^3ft boc with a port tuned to ~17hz. I'm unsure how close to xmax I should really allow the drivers to get but model shows spl that I will probably never even want to hit. Usually will be using half this power at most just to be safe and it should still be plenty loud if my understanding is correct. I wanted to try to keep the response as flat as possible as low as possible because it's going in a very large room that probably won't provide much gain.

I have a peq filter at 20hz +4db q=1 with a buttersworth 4th order at 14hz to keep xmax under control below tuning and still keep as much output as possible. The group delay is a little concerning, but from what I've read is mostly a non issue at the frequencies that it's so high at. Right now I have a Bheringer 3000D in mind for the amp. I'll get the 4ohm DVC version of the driver an wire in parallel to 2ohms for the amp. Limit to 27v ~500w(may not make a lot of sense but will give me plenty of headroom). The PEQ may be a bad idea but I'm unsure.

Suppposedly F3 will be ~18hz F6 ~16hz F12 ~13.5hz. Peak excursion right at 26mm at 13 and 25hz. Xmax for the driver is 28.4 so Maybe that's pushing it, I just don't know but also real world will almost never be driving it at these levels. Also db is at 2.2 meters. Air velocity right at 25m/s. That is the part that is probably wrong but I can figure that part out a little better when I actually make a finalized box design once I know I'm okay to move forward.

I originally was going to do a "VTF" dual port design because I thought the idea sounded cool but I realized how little I would ever change the tuning plus how impractical it would be. I can send the modeling I got for those as well if this one is completely wrong, but if that's the case those probably are too.

Thank you to anyone who can take the time to help educate me. I really appreciate it!!

To be honest that does not look a very promising driver. It is high Qts (0.57), and has a a very high F3 (33Hz). Generally high Qts drivers are best suited for sealed application, but with an Fs that high it will not be much of a sub in a sealed box. Have you bought it yet? If not, don't.

 

[NathanC]

To be honest that does not look a very promising driver. It is high Qts (0.57), and has a a very high F3 (33Hz). Generally high Qts drivers are best suited for sealed application, but with an Fs that high it will not be much of a sub in a sealed box. Have you bought it yet? If not, don't.

Thank you for the reply, I've seen two different sets of t/s for this driver and think that I read that the ones on the manufacturer site have been confirmed incorrect. Didn't make much sense because I'd think that they'd change them. The other set of parameters I've seen, and what I used in WinISD show Qts (0.42) and Fs of 23.8

 

[TLS Guy]

Thank you for the reply, I've seen two different sets of t/s for this driver and think that I read that the ones on the manufacturer site have been confirmed incorrect. Didn't make much sense because I'd think that they'd change them. The other set of parameters I've seen, and what I used in WinISD show Qts (0.42) and Fs of 23.8

That sounds a lot more promising and I suspect it could be modeled sealed or ported. Those original numbers you posted would make it totally useless as a sub driver. The problem is, you have to ask which numbers are correct? The manufacturers site should have correct numbers, if not it makes you really wonder about their quality control and if they can be trusted to make a consistent product. I would avoid them like the plague if I were you.

 

[NathanC]

I hear that for sure! Is there a way for me to test the important t/s parameters myself? If it's doable I might would order one and if it's close to Qts .42 and Fs 23.8 I'd keep it and build an enclosure. Otherwise just return it. I haven't found another driver around this price with what could be similar output. I may just not be finding them though. Do you or anyone have a good/better driver you'd recommend in the ~350 dollar range?

 

[NathanC]

Do these measurements help? From their website. https://stereointegrity.com/wp-content/uploads/2021/05/SQL-15.pdf

If I'm reading this right it has an Fs of closer to 13-14hz and Qts of < 0.4 for much of the excursion range. Is that possible?

 

[TLS Guy]

Do these measurements help? From their website. https://stereointegrity.com/wp-content/uploads/2021/05/SQL-15.pdf

If I'm reading this right it has an Fs of closer to 13-14hz and Qts of < 0.4 for much of the excursion range. Is that possible?

Not likely. What are your requirements and we can see if we can find a suitable driver?

 

[NathanC]

Not likely. What are your requirements and we can see if we can find a suitable driver?

I didn't think that sounded right. Would like to be able to play flat to ~20hz at least. Normal volume will probably not exceed 90-95db but would like the capability to play reference or at least bass peaks of 105-110db if I want and for the headroom/peace of mind. I have fairly high end, albeit older, bed layer speakers so would like something to match their quality if possible. Paradigm signature s8 v2 towers the C5 center and ADP3 surrounds with the original/not new model m&k s150 as rears(unless that's a bad idea but I think it's probably fine). I'm in a large room so not much gain from it. Smaller the box the better but open to building whatever is optimal for the driver/current layout honestly. Plan to build a second sooner rather than later, and possibly a 3rd much further down the line of whatever I wind up doing. For now I only plan to build one to see how it goes. If I'm happy with it it'll push the timeline for the second and third further, but will still eventually do it for a more even response throughout the room.

Thank you for the help!