Which enclosure design program?

[georgehifi]

Hi, I've just got some new ACI SV12 12ins lf drivers can you guys recomend the best sealed box design program that takes into account various amounts of stuffing.

Thanks George

 

[Ron E]

The best?

LEAP

Second best:
Any free triple-damped simulation
Unibox, WinISD (pro only)
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Would it surprise you to know that T/S is not the full story and that it is only accurate within ~5-10% anyway? To really design for stuffing, you would need to measure, model, stuff, measure, compare to model, change model, etc... and iterate through the last three for every little change in stuffing.

So as far as designing for stuffing, there is a limit to how well you can predict it - but sealed designs are very forgiving and it doesn't matter you won't hear the difference between Qtc=0.707106 and 0.72 anyway

 

[georgehifi]

Thanks Ron, I can't afford Leap, but got Unibox it seems great for the job, I have a 85lt sealed box, and acording to Unibox if I stuff it 100% I'll have a QTC of .66 and a F3 at 33hz, couldn't ask for better, but that's acording to Unibox, if you have the chance can you run the specs through Leap if you have it to see if the megabuck program gives the same results?

Cheers George

 

[Ron E]

Those parameters you provided are interesting, the Cms and Mms combine to give a resonant frequency of 15.7 Hz and Cms and Mms combine to give a Vas of 310 Liters. In other words, the parameters are not consistent or correct.

Trying to "perfect" a design using inconsistent (or any) published parameters is pure folly. You will need to measure the parameters of your driver.

If one ignores the inconsistency in Cms-Mms and just uses published Fs, Vas, etc... your specified box will work fine pretty much as specified by Unibox. If the published Cms/Mms are instead correct, you will have a Qtc of ~0.74 in the same box. This is according to the simulator I wrote, which is similar to Unibox. I don't use LEAP, but the sims from my model match the LEAP "quickbox" simulations - they use the same model.

BTW, This driver doesn't model as having a very good powerhandling below 40Hz or so, but it is quite efficient compared to many typical long excursion 12" drivers.

 

[georgehifi]

Thanks for your patience Ron, this driver is to replace the Custom Eminence one that Martin Logan used in their Monolith III electrostatic hybrid, the Eminence one was very poor (specs below)
I have been searching for a long while to come up with something that goes reasonably low in the Monolith 85lt sealed box, and that can have some thing up higher. This SV12 was the best I could find in a 12ins, the cross over is 125hz 12db per octave.

Cheers George

 

[Ron E]

The sensitivity of the Eminence driver is:
92 dB with 1 watt, but 96 dB with 2.83 V

The sensitivity of the AC12 is:
87 dB with 1 watt, but 91 dB with 2.83 V

The AC12 will be 5dB quieter for the same input power.

If your system is Biamped, you can adjust, but if connected to a passive crossover you need a more efficient woofer or some way to attenuate your panels.

 

[georgehifi]

The sensitivity of the Eminence driver is:
92 dB with 1 watt, but 96 dB with 2.83 V

The sensitivity of the AC12 is:
87 dB with 1 watt, but 91 dB with 2.83 V

The AC12 will be 5dB quieter for the same input power.

If your system is Biamped, you can adjust, but if connected to a passive crossover you need a more efficient woofer or some way to attenuate your panels.

Yes I am bi-amped Ron, and I do change if the feedback a little on the amps to get the right gain if needed, but but to my surprise they are equal in volume, I'd say that the Eminence is fudging with the efficency and the spec is really 92db at 2.83v not at 1watt.
Below is the xover that's used.
Cheers George