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Replacing subwoofer

post #1 of 10
1/14/09 at 2:28pm
Thread Starter 
Hey everyone, hope you all had a safe and happy holiday.
It's been a while since i've posted on here but i figured this is the best place to come for audio advice!
Recently my subwoofer, PSB Image Subsonic 6 12" had fallen ill, making very odd noises while in use. Took it in for evaluation/repair and turns out there was an issue with the woofer itself, it had sustained damage that was not visable to the untrained eye. In the end the repair shop had put in an 80$ aftermarket woofer. Im not sure if this is the brand but it says "acoustics 2000" in the center and has an orange foam surround. The repair man did inform me that there would be a performance drop off, but for 80$ i figured it was better than no low end at all. Well after getting by with it for a couple weeks i've decided it's just not cutting it. Now what im looking for is suggestions on a better subwoofer to put in there, or if it's even worth it. Like i mentioned previously its a PSB image subsonic 6. Now apparently there are some variations of this model, mine is plain black and looks identical to this one shown here TechnoFILE Looks at M&K and PSB Subwoofers (the second one). I'm lookin at a budget of about 200-300$. Thanks in advance
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post #2 of 10
1/14/09 at 3:11pm

Re: Replacing subwoofer

Attempting to just replace the driver may me throwing more good money after bad. Wish you would've come here first before letting the "repair shop" (PSB authorized?) put in a generic woofer. Why didn't you just contact PSB to price a replacement if it was out of warranty?...driver's usually have a 5 year warranty, BTW.

The important thing to retrofitting a driver is knowing the net air volume, and in this case the tuning frequency. Your link quotes 1.64 ft^3 for the internal volume and it looks like that was probably net volume, which is good. However, later versions say 2.38 ft^3, so the Sub6 grew over time...grab a tape measure and tell us which one you have.

While you're measuring, get the port lengths as well. We can back into the cabinet's tuning by knowing the port diameter, length, and net cabinet volume.

The biggest problem may be the amp. There's a good chance PSB dialed some custom EQ into the amp to assist the driver. We could come up with a driver that works great on the assumption the amp is flat, but any custom EQ could leave it sounding less than optimal.

-Brent
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post #3 of 10
1/14/09 at 3:20pm

Re: Replacing subwoofer

Everything that Brent said plus we need to see the replacement driver outside of the cabinet. Most stamped steel frames are the same size. If it is a cast aluminum frame then those vary by type. Finally what is your budget for this? I know where to get drivers from $50 to $500.

-Robert
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post #4 of 10
1/14/09 at 5:18pm
Thread Starter 

Re: Replacing subwoofer

Hey guys thanks for the quick responses.
The sub is JUST under 20 inches tall and about 13 inches from front to back
And i was looking to spend about $200-$300

And to answer your other question Brent, i bought this second hand for $175 with no papers or receipts or anything. So the local repair shop was my only option I suppose.


Edit: The 2 ports are about 2 inches in diameter and about 8 inches deep
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post #5 of 10
1/14/09 at 7:23pm

Re: Replacing subwoofer

Are those measurements estimates? We also need the width. If you measured the outside, we need the thickness of the material used to build the box. Then we can find the net volume as well as the tuning frequency of the sub.

Based on the enclosure size, I'm already looking at either the Dayton Reference High Output sub or the Dayton DVC 12". But once you post the exact size I can run simulations using Unibox.

-Robert
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post #6 of 10
1/15/09 at 4:58pm
Thread Starter 

Re: Replacing subwoofer

I took out the Woofer from the front and there is a part 'shaved' out of the MDF for the woofer to go in flush. The MDF NOT including the groove is 3/4 of an inch thick, and the thickness of the groove is 3/8's thick.
Top to bottom is 19 3/4". Front to back is 13 1/4". Left to Right is 15" even.
Ports are 8 3/4" long. Hard to get an EXACT measurement on the port because its flared, but it appears to be about 2" dead on

Edit: the woofer on the back says
2000 acoustics
8 OHM 300 watts
A12308
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post #7 of 10
1/15/09 at 7:12pm

Re: Replacing subwoofer

Based on that information, you have a net 1.67 cubic foot enclosure tuned to 33hz. For a ported box, that is tuned WAY too high. The SVS NSD10 sub is tuned right around 20hz. That is almost an octave lower. Ported subs don't really have much output below their tuning frequency.

If you are going to do anything to that box, I suggest that you remove both ports and seal up the holes. But Brent also brought up the issue of built in EQ on the amp. We don't know if the factory amp has a sub-sonic filter at 30hz to filter out the low bass. I would if my sub were tuned that high.

-Robert
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post #8 of 10
1/18/09 at 1:18pm

Re: Replacing subwoofer

Assuming no special EQ in the amp, the smoothest response I can come up with in 1.6ish ft^3 and 32-33hz tuning uses either the 12" Polk driver at mavin.com ($45) or a driver I found in my database simply labeled aw1200. Unfortunately, I have no further information about this mystery driver known as the aw1200 and Google doesn't turn up any. I entered it back in 05/2007 and wonder if it might have been one of the MA Audio drivers carried by Parts-Express around that time.

This is by no means an exhaustive check of every driver option available. It does indicate you're looking more for a "car" oriented driver...low Vas, relatively high Fs. There are several small box "usual suspects", such as the RS315-HO ($140) that Robert mentioned, that could work if you could get the tuning frequency closer to 20hz. Lower tuning requires longer ports, which are hard to fit into your box and consume additional net volume inside the box. Additionally, something like the 315-HO would be leaving a lot of performance unused with only 130 watts on tap.

Your best bet is still probably to contact PSB about a replacement driver, IMO.

-Brent
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post #9 of 10
1/20/09 at 10:13am
Thread Starter 

Re: Replacing subwoofer

Thanks for all the input guys, I appreciate it. From the sounds of things im probably just going to tough it out with this woofer and save up for a whole new sub woofer.
I do still have the original damaged Woofer. The damage appears to be so minimal, it almost seems like it could be repaired, but i know nothing of the sort. When not in use there is no visible damage, but when you gently press on the woofer, there is the smallest bend right near the center, no tear or anything, its just "weakened" if you will. The man at the shop said hes never seen anything like it before; outside the box, the woofer performs just fine, but inside the box is when the noise is heard, is there anything i could to do "strengthen" the weakened spot? Im guessing its some sort of vibration that causes it. Im talkin out of my arse here, but is there some kind of adheisive or anything to stop it?

Thanks guys
-Ryan
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post #10 of 10
1/20/09 at 12:46pm

Re: Replacing subwoofer

Pictures of the damage would help answering your repair question.

-Robert
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