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Discussion Starter #1
I'm looking to build or buy dual subs for my basement rec room but have some pretty limiting WAF considerations with respect to size (14" to 16" cube max). Budget is $1,000 to $1,500 all in. Looking at sealed options, the SQL-15 (+NX6000) and the Rythmik L12 seem to offer the most output in a small form factor within my budget. I'd expect the SQL-15 project, with its 15" driver and 3,000 nominal watts per channel (more like 1,375 peak watts at 20Hz per notnyt's testing if I'm reading it correctly) and large xmax, to trounce the L12 with its 12" driver and 300 watts RMS, but WinISD doesn't seem to say so. Wondering if I'm doing something wrong or overlooking something.

For ease of comparison, I'll examine peak output at 20 Hz at 1 meter. Translating numbers from databass, the L12 seems to do around 104 db (95.1 db 2m groundplane RMS + 6 to convert to 1m + 3 to convert to peak).

Modeled in WinISD, the SQL-15 (in a 2 cu. ft. sealed box @ 1,375 watts) seems to have max SPL of 105 db at 20Hz at 1m (groundplane?). So only about 1 db difference!

I know Rythmik's servo design has magical properties, but I find it hard to believe servo would be able to overcome the size, power, and excursion deficit against the SQL-15. Dual L12's would come in cheaper than the dual SQL-15 project to boot.

This would be my first DIY project, so I'm not sure if I'm thinking about this correctly. Appreciate any input. Thanks!
 

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Rythmik has the F15HP and it equivalent product in Kit form which might compare better to to the SQL 15. They also have the Seald F18
 

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For ease of comparison, I'll examine peak output at 20 Hz at 1 meter. Translating numbers from databass, the L12 seems to do around 104 db (95.1 db 2m groundplane RMS + 6 to convert to 1m + 3 to convert to peak).
Are the values listed in that table peak or sustained output?

It seems you are assuming they are sustained output, but why are you adding 3dB to convert to peak if comparing with WinISD, which should correspond instead to sustained output?
 

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Discussion Starter #4
Are the values listed in that table peak or sustained output?

It seems you are assuming they are sustained output, but why are you adding 3dB to convert to peak if comparing with WinISD, which should correspond instead to sustained output?
Thanks for the reply. I think part of my potential issue relates to making sure the different data sources are apples to apples, and your question gets to that.

The L12 data essentially comes from databass (they haven't directly tested the L12, but based on other Rythmik subs they have tested and Rythmik's own data for relative output at 20Hz across their product line, the linked table essentially estimates what the L12 would do if tested by databass). I understand the databass data to be 2m groundplane RMS under the CEA 2010 testing method. They say to convert to 1m peak, you should add 9 db, which is what I did.

I've assumed WinISD's max SPL graph is also showing peak numbers since it's labeled "Maximum SPL", but it sounds like that might not be the case. I suppose another potential inconsistency might be that databass uses the more strict CEA method, whereas WinISD presumably doesn't factor in distortion when reporting max SPL, but that would lower the SQL-15 SPL further if you were somehow able to determine a CEA 2010 passing score in WinISD.

I guess the heart of my question is to how to make the databass and WinISD data consistent. I'm fairly certain how the databass data is reported, but I'm less sure about WinISD. Thanks!
 

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Rythmik DS 1200 (driver used in the L12) in a 1cuft box (approximated from L12 dims on website) with 300watts.
SI SQL 15 in 2cuft box with 1000watts. Max SPL Tab, SQL will take more power and isn't even close to xmax at 1500w.
Not even in the same ball park.
WinISD is anechoic. Ground plane adds 6db I'm pretty sure. Not sure what the other 3db is added for.
 

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Discussion Starter #6
Rythmik DS 1200 (driver used in the L12) in a 1cuft box (approximated from L12 dims on website) with 300watts.
SI SQL 15 in 2cuft box with 1000watts. Max SPL Tab, SQL will take more power and isn't even close to xmax at 1500w.
Not even in the same ball park.
WinISD is anechoic. Ground plane adds 6db I'm pretty sure. Not sure what the other 3db is added for.
That's more like what I would have expected. I appreciate you running that.

I had seen conflicting information across the internet about whether WinISD was reporting groundplane or anechoic SPL, but that seems to confirm that it's anechoic. If the databass estimate for the L12 is 95.1 db (2m, groundplane, RMS), and your WinISD graph is showing ~95 db at 1m (and presumed anechoic and RMS), then -6 db going from 1m to 2m +6 db from anechoic to groundplane essentially gets you back to the 95.1 db (2m, groundplane, RMS) estimate from databass. Thank you!
 

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Discussion Starter #8
Usually the best way to get loud is to maximize the cone area and the number of coils.

If you are limited to 16 inches cubed you should model what 6 of these would do in such a box.
https://www.parts-express.com/dayton-audio-ls12-44-12-low-profile-subwoofer-dual-4-ohm--295-253
One per side and then add some feet, or just limit it to 5 cones.

See if that is loudest.
Won't be cheap though...
Gotta love AVS. Thanks for the out of the box, or really, all over the box idea. I modeled it out of curiosity, but 6 of those don't even seem to match one SQL-15 below 50 Hz. Box size at 2 cu. ft. seems to be the severely limiting factor. WinISD suggested something like 8 cu. ft. IIRC. Fun experiment, but oh well. Seems like the SQL is the way to go.
 
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