Already have a prebought sub/box/amp can I mod it for deeper bass?

[dcourtney]

Hi Guys

I recently picked up a set of accusound speakers which I have been pretty happy with. Unfortunately the Sub only goes down to 35 which isn't cutting it for home theatre. Before I take the drastic measures of buying a completely new sub/box/amp I was wondering if it would be possible to reuse the existing box and amp and just replace the driver? I have very little understanding when it comes to this kind of stuff but do know that sub drivers are very dependent upon the box and amp but I figured I'd ask anyway.

The specs of the sub can be found here (the reference 8 set)
http://www.accusound.com.au/signature.html

SUBWOOFER
Frequency Range 35Hz-150Hz
Power Handling (Watts RMS) 150 (built in 240V amplifier)
Bass Drivers 1 x 250mm Woofer
Dimensions (mm)
H 460
W 311
D 432
Weight (kgs per speaker) 24.2

The box also has two ports firing downwards.

Please let me know if you need any more details.

Look forward to your replies

[richie00boy]

Chances are you can't do anything as it's only a relatively small drive unit, the tuning of the box is probably limiting your extension and you'd run out of amp power if you start applying boost. You might as well start again from scratch as you'd have to change everything anyway, may be able to use the same drive unit.

[paulspencer]

Since it's a small vented sub tuned quite high, there's not much you can do with it to get more extension and output. The driver probably doesn't have the capability to get down any lower with authority, so they tuned it fairly high. I'd say sell it and get what you can, then spend a bit more and you will get something FAR better. Put a decent 12" driver in a decent sized box and you can easily get down to 20 Hz. For about AU $700 you can do a pretty decent sub.

[simon5]

At first, he could try sealing one port to see if the driver can take it.

It'll be tuned way lower with one port closed.

[lynchingacers]

FOR ME I DID KINDA THE SAME THINGI JUST USEC THE ORIGINAL AMP THAT CAME WITH ANOTHER STERES LEFT IN THE BOX AND RAN TTHE WIRES TO MY CUSTOM SUB AND BOX I BIULT the amp works fine and is perty loud but the amp was biult for a different stereo tho

[dcourtney]

Hi Guys

Thanks for your advice it's appreciated.

One thing I forgot to mention is I really like the small size of this box it fits nicely in my room. All the DIY options appear to need a much larger box

Also $700 is pretty close to what I spent on the entire speaker setup so it would hurt putting that into a sub that I'd use quite rarely. I use the system most of the time for hdtv playback, music and xbox gaming none if which seem to use the sub a whole lot I do watch some dvd's but have to keep the volume relatively low or the family will show me the door :/

Does not needing a whole lot of volume help amp wise at all? I guess if I could find a design with a similar sized box I would look into it.

As for sealing one of the ports what am I risking by doing that? could I pop the driver?

thanks again

[Cal Weldon]

You probably won't do any harm by plugging one of the holes but I am curious as to how you have the frequency cut off set and what the gain and phase are set at. Have you fooled around with those to see if you can get it to sound better? The reason I'm asking is a couple of occaisions I've heard people say what you are, only to find out they had not optimized their system to the room. They had taken the woofer out of the box and not bothered with any controls other than the gain on the plate amp. All I had to do was to lower the frequency and add some gain. 35 Hz is really low. 35Hz is below my hearing range. Many times I've heard people talk about a 20 Hz signal knowing very well that we were dealing with harmonics, not the original signal. In fact one of the better HT set ups I've heard used an 18" PA driver for the low end with a cut off of about 40Hz. This set up darn near crushed your chest.

I currently use a 10" woofer in my HT in a 250 sq ft room with no concerns at all.

Cal

[simon5]

You don't risk anything by closing one port at lower volume levels. Then, slowly bring the volume higher and higher on a heavy bass track.

If the subwoofer is starting to make awful or bizzare noises, then you can't go higher. If that volume level is enough for you, great. If it's not as loud as you like, then you'll need to upgrade my friend if you want more low bass.

Good luck!

(Btw, yes your box is quite small, but it's possible to stay small, with drivers like AE speakers)

[BassAwdyO]

I can hear down to 24hz at less than 110db thank you very much.

I vote for blocking one port also... the worst you can get is chuffing... it wont damage the driver

[dcourtney]

Hi Guys

Thanks again for your input it is really appreciated. Adjustment wise I'm basically running it all from my receiver (denon avr2805) I've run the auto setup with microphone, I have the xover set to 80hz on the Denon and turned up all the way on the subs amp. The actual volume dial is only at about 1/3 on the sub but I was more concerned with frequencies below 35hz as I quick ran some test tones and couldn't hear or feel much coming from the sub.

I will try blocking one of the ports if I can find something to fit in the port, May I ask why would the designer put two ports in if it may have better low down response with only the single port?