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Have an older SVS 25-31PCi sub 300watt Bash Amp. Its from 2006-2007 and discontinued in 2008. I've been thinking about upgrading the driver. The SVS Peerless offering in the current NSD line is fairly expensive. I contacted Parts Express to ask how the TC Sounds Epic 12 would work in the enclosure and they think it would work fine.

Anyone else think it would work out ok?

31" high x 16 across. 3.6 cu ft. Port tuned to 25hrz

Thanks
 

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The model I have has only 1 port. Inside diameter is about 5"-5 1/4" by 13" long. Does that affect the model?

Thanks gperkins for taking time out.
 

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But I have to ask, why upgrade the driver? Is the current one damaged? If not, utilizing the same enclosure and amp, won't result in much of a change in performance/output unless your current driver is being pushed past xmax.
 

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That size port raises tuning to around 30hz which is too high personally. It would need to be 19" long if it was 5" round. Can you modify the port by putting a new one in. And would there be room for a longer port.
 

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But I have to ask, why upgrade the driver? Is the current one damaged? If not, utilizing the same enclosure and amp, won't result in much of a change in performance/output unless your current driver is being pushed past xmax.
Curiosity really.

Its one of the older stamp steel baskets from 2006-2007, PCi. I deleted the email but I though SVS's tech guy said that going to the new customer Peerless driver they use in the NSD could see a 3db output compared to the older driver.

I may just sell the SVS and use that toward a PB12+.
 

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GT, you posted the numbers for external dimensions, including the gap between the driver and the base plate. To model a speaker, you need the internal net air volume of the cabinet. So, you need to use the height of the cylinder itself, not the cylinder + base. Then, you need to subtract the thickness of the top and bottome end plates (hint, they're inside the cylinder so you'll need to remove stuff). The thickness varied with model, but could be as much as 1.5" on each end. IIRC, the OD is 16" so the ID is probably closer to 15.5". IOW, figure 3 ft^3 to 3.25 ft^3 is more realistic for a 25-31, including the effective volume gained due to the cylinder being lined with fiberglass insulation. Someone on AVS took a 20-39PC+ apart and measured to be ~3.7 ft^3 gross (ignoring port/driver/fill) so assuming 15.5" for the ID, the internal height of the 20-39 cylinder is 34".

As Looney mentions, you won't get more output if you're not running out of excursion with the PCi driver. Efficiency is governed by the enclosure so any 12" driver (assuming suitable Xmax and equivalent Sd) will produce the same SPL with a given power input. The Epic12 likely has more Xmax than your PCi's driver so if the PCi's not running out of Xmax before the amp runs out of power, the Epic12 won't give you any more. The amp's built-in HPF will make any difference in below tuning rolloff a moot point as well.

Gperkins, the PCi series use a single 4" Precision Port...possibly with a custom length since the 17" effective length available to the public wouldn't achieve the spec'd tuning frequency.

-Brent
 
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