SAL Full Range Drivers

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frugal-phile™
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Sims suggest as large a box as you can live with sealed or aperiodic OR open baffle.


dave
 

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diyAudio Editor
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If you want to do it the easy way like Nelson, here are some really nice 1 cu. ft. cabinets from Parts Express

https://www.parts-express.com/dayto...ft-mtm-curved-speaker-cabinet-cherry--302-753

Best I can figure from the specs they are 208.6 mm wide at the baffle, which is about 8.125" I believe. I think the baffle is solid. It's the bracing that has the 2 holes IMHO so the 8" driver frame should fit. -barely. These are an MTM model, it's a shame they don't seeem to have a "2-way model which are a bit wider.
 
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diyAudio Editor
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I believe the one I linked to is curved, so they seem to still be making the MTM ones.
Maybe that bump gives the illusion of bass!

Probably best plan to make a rough set of bigger boxes about twice the size to test, About the size of a Large Advent, if you go back that far..
 
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I believe the one I linked to is curved, so they seem to still be making the MTM ones.
Maybe that bump gives the illusion of bass!

Probably best plan to make a rough set of bigger boxes about twice the size to test, About the size of a Large Advent, if you go back that far..
IIRC those large Advents were 14"W x 26"H x 12"D.
Dave's sims indicate a 200L sealed box F 75hz., something like a 14"W x 42"H" x 22"D behemoth!
 
Sims suggest as large a box as you can live with sealed or aperiodic OR open baffle.

I can't stop but think that aperiodic is a very cool idea for this driver. I have never actually messed around with an aperiodic, so I don't really know where to look and how to do it. Are there any reports related to the SAL driver in an aperiodic box out there? Anything specific to watch out for? Box size, design of the vent?
 
diyAudio Editor
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Well an aperiodic box design would be pretty cool as a project for all our benefit. That's what I'm talking about- a stable of various designs for various uses. At the moment the SAL drivers are very new, so almost nothing out there except for Dick Olsher's open baffle and Nelson's future designs..

But as Nelson Pass says, they sound darned good in the small box actually, while you're building your open baffle , aperiodic, or other more complicated speaker.
 
frugal-phile™
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I can't stop but think that aperiodic is a very cool idea for this driver. I have never actually messed around with an aperiodic...

I am faced with similar design issues with some Visaton B200s i want to put in a box. Fortunately one of my gurus as i was learning speaker design did a huge amount of real research on Aperiodic enclosures so i have a good grounding in their design. Modelling them is tricky (if MJK’s modeler was calibrated for hign desities of damping it could probably do it, and AKABAK might) so cut & try is the way forward. With these i’d consider a 75-100 litre box, then you start drilling holes in the back of the box as far away as you can from the driver and heavily damp the holes from the inside using compressed fibreglass, ultra touch, or high density open cel foam. The rest of the box should also be heavily damoed but with a lower density path from the back of the driver to the vent. You iterate until GMs clik test sounds right or the measured impedance has maximized the supression of the impedance peak.

This cross-section of the PR200 (an advanced aperiodic box) gives some ideas on this approach.

D67FEC35-4E27-416E-8CB8-DA78DD091F81.gif

dave
 
frugal-phile™
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That's frighteningly touchy feely! No precise edges to measure :)

decidedly old school, but there is a broad sweet spot so not as tedious as it sounds. I have built more than a few aperiodics using this receipe.


or: just make the open baffle with a woofer. I think the crossover could be lower than other full ranges, so more cohesive sound from the SAL driver.

If you can live with, or like, open baffles. We have tried more than a few and something just doesn’t ring true. Reason why my next B200 build is in a box.

dave
 
diyAudio Editor
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Yes, it was more a comment on myself and others that we all like certainty and a recipe for success. I'm certainly like that in audio! I'll bet there are ways that once an "optimal" design was determined that a process could be defined to reproduce it accurately.....and great to hear it doesn't have to be THAT accurate!
 
I am faced with similar design issues with some Visaton B200s i want to put in a box. <snip>

I guess all it takes is to measure the impedance curve of the aperiodic system and tweak the impedance peak shape until it matches the desired Q of the speaker system by varying the stuffing of the box and the "leak". The SAL (and the Visaton B200) both have a Qts of around 0.75, so very close to but slightly higher than the "optimum damping" of Q = 0.707. If I understand things correctly, this means that it would be best to get as much damping as possible from the aperiodic box in order to not raise the system Q much higher than the Qtc of the driver. I'd like to stay at Q < 0.8 or so to avoid peaking in the bass response.

This sounds like I should give it a go. It's easy to make and tweak, and even newbies would be able to build this. Just give me a pair of SAL drivers and a week of holidays and I will be all over it!
 
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