O Audio 500W Bash(R) Subwoofer amplifier?

[gasdqman]

The O Audio 500W Bash(R) Subwoofer Amplifier seems to have some interesting features at a reasonable price.
I only have room for two 15" Woofers so it should be more than enough power.

Could the combination of

"Selectable low frequency EQ/subsonic filter" and the
"Parametric equalization for room mode control"

provide enough equalization to eliminate an additional piece of equipment?

Any comments are welcome. Thanks.


www.oaudio.com/500W_SUBAMP.html

[jimlowe]

I think you will want a separate EQ like a bfd, this only has one band, not really enough in most rooms imho. The price is attactive, but I think it makes more sense to buy a pro amp like the nady or behringer and save for a BFD. But for the rumble filter, 500watts, and one band para eq, not a bad deal I guess, especially if you are planning on keeping your system completely unchanged. If you like to change things around ever couple of years though, a separate amp and eq make for an easier upgrade path.

edit. Another thing to consider is stereo pro amps have more versatile wiring options to run the drivers in 4ohm operation, single channel plate amp has limited wiring options.

[ThomasW]

I've yet to see anyone get by with fewer than 5 bands of EQ after flattening their FR and creating a house curve.

[ryans]

Jim's comment about wiring options is right on. Typically the woofers we're using are 4 ohms SVC. So dealing with a pair of these you'll only get 325 watts@8ohms out of that amp. That's probably plenty for 2 woofers, but still its not really getting the most out of that amp.

I'm a plate amp user but only because I had one sitting around already. I'm running a 4ohm load (4 woofers series-parallel) for maximum power from the amp.

[gasdqman]

I have read the response to my question and many others. The following setup is a result of what I have inferred from all that I have read. I’m not completely convinced that these inferences are correct. Does this setup make sense?

My pre-amp has two sets of stereo outputs (I presume that if it didn’t, splitter cables could split the signal into two outputs.) One set connects to a power amplifier then to stereo speakers. The other set will go to a BFD. The BFD will connect to a NADY 900 power amplifier. Each output of the NADY will be connected to an 8-ohm, 15-inch IB woofer.

I need the BFD to do three things. The first is to make the signal more pleasing from, say, 80-Hz down to as low as it will go. The second thing is to roll off the signal everywhere above, say, 80-Hz. The third is to coordinate the phase with the stereo speakers, although I don’t anticipate much need, as the distances to the listener are similar.

The volume controls on the NADY will be used to match the volume of the subwoofer to the volume of the stereo speakers at common frequencies. I hope that the pre-amp volume control will be all that is necessary for adjusting sound level for most situations.

A stereo to mono adapter could be inserted between the BFD and the NADY, the NADY could be bridged, and the woofers could be wired in parallel to make a 4-ohm mono-woofer. This provides more output power, and may make the subwoofer impedance a better match to the stereo speakers.

Am I expecting too much from the BFD? Can the volume be successfully controlled by the pre-amp?

[ThomasW]

First the BFD isn't not a good substitute for a proper crossover and shouldn't be used as such. Second it has no control phase.

Normal phase controls operate only at the crossover frequency. If you need more sophisticated phase adjustment, the price of admission is really high...... google 'DEQX' for info

If you don't have a subwoofer output from your preamp, then consider getting the Behringer CX2310. It's ~$90 and is a VERY good crossover.

Finally it's not necessary to have the impedance of the sub match that of the mains.

[chrisbee]

I am using the Behringer CX2310 (and BFD) on Thomas' recommendation. I was just going to borrow my Bash plate amp from my SVS as I wasn't intending to use the cylinder sub any more.

I had serious doubts about inserting a cheap pro-gear box of electronics between my precious stereo preamp and power amp. (this crossover costs just a little more than the amp manufacturer's standard interconnecting cable!)

My fears were groundless and I had to admit to a considerable improvement in sound quality since the insertion of the crossover. This came from unloading the deep bass from my speakers. The speakers were 40Hz floorstanders and I'm using an 80Hz crossover. Since the CX2310 offers a 24dB/octave slope it works wonders! A typical plate amp would only give you a passive 6 or 12dB per octave reduction from its crossover.

The 5 channel CX2310 also gives you the option of adjusting the gain on each channel (and on the additional subwoofer mono channel) which offers even greater flexibility.

I use the CX2310 in double stereo with the stereo speakers on the High channel with their own power amp. The Low channel is used for the IB using a BFD and EP2500.

Stereo channels allow much greater flexibility in wiring options for the IB drivers since you have two channels to play with rather than just one. I'm running 2 sets of 2 x 4 Ohms drivers in series for 8 Ohms per channel. A mono amp would have required a series-parallel configuration with a considerable reduction in overall power per driver using a plate amp. The E2500 thrives on very high settings on its twin control knobs.

The increase in realism since installing my IB is startling. I'm still primarily a stereo music fan and only watch about one new DVD film per week. Though we also use the system for watching favorite "action" satellite TV programmes. It lifts the sound quality into another dimension compared with the TV speakers.

I actually went off to answer the front door when somebody knocked on a door on a TV progamme. There was nobody there! And no, it wasn't The Haunting. ;D