2.0 + 3.1 = ?

September 10, 2006 12:30 PM

Surround Sound 2.0 setup: What do I do w/ my new amp and old speakers?

I have 2 old Boston Accoustic "a150" 100 watt speakers, and a powered yahama 'inline' subwoofer. My old amp is dead, now I have a new (to me) Denon AVR-2700 surround sound amp.
Basic question: do I now also need 3+1 more speakers to make life complete? Or can I get reasonable performance from my old speaker setup?

Additional info: I'm just fine with how music and movies sounded on my old Stereo amp.

Extracredit:
* If I need 5.1 speakers, do I need to go out and get matched speakers, or can I use my 2 A150s as 'fronts'
* Is it reasonable to run my built in TV speaker (from a huge old Toshiba Cinema Series TV) as my 'center' channel?
* What am I loosing out on if I don't move to a 5.1 speaker setup?

Thanks in advance...

posted by daver to media & arts (6 comments total)

What you're losing out on is the full home theater sound experience. If you've never heard this you might not really miss it. Once you've heard it, however, you will probably want it.

If you wanted to get surrounds, then the best thing to do would probably be to buy additional Boston Acoustics components. You do want all your speakers to be "matched" so that sounds don't change timbre as it moves from one speaker to another -- it can be very distracting. A BA dealer might could tell you if any of their current line sounds enough like your A150s to blend in.

If you want a taste of the surround experience, you could look into virtual surround technologies, such as the one SRS Labs offers. These purport to emulate the additional surround channels using only two channels by means of psychoacoustic principles. They are not as good as having the real thing, but if you are sitting in the "sweet spot" they can be fairly convincing, and better than just plain stereo. If your receiver doesn't have such a circuit built-in, you can buy an outboard unit that has it, and plug it into your receiver's EQ loop (assuming it has one) or between your DVD player and your receiver.
posted by kindall at 12:41 PM on September 10, 2006

Get a centre speaker at least, or use the TV's internal one if it has that ability. Dialog split between two speakers sounds incredibly unnatural, though I guess you've got used to it.
posted by cillit bang at 12:46 PM on September 10, 2006

Most 5.1 amps don't develop very high DC power supply voltage, in comparison to big stereo amps and receivers, simply because they are going to be feeding current to 3 or 4 additional amplifier sections, and the power supply in a 5.1 amplifier can only be physically so big, even if it uses advanced switching supply design, toroidal transformers, and high quality, dense capacitors. 100 W total output, from 5 channels, is only 20W per channel. But your Denon appears to be in the upper range of multi-channel amps with 80+ watts of clean power available per channel, so you should be able to run conventional speakers.

Generally, because of the limited power available from surround sound amps, multi-channel speaker sets are engineered for fairly high efficiency, meaning they generate relatively high sound pressure levels for the electrical energy they are supplied. They often adopt small, full range drivers as their main components, and eliminate the passive crossover networks and pads of more sophisticated multi-driver speakers, such as your A150's. So, to get reasonable SPL, the multi-channel systems generally sacrifice being truly "flat" in terms of frequency response. Thankfully, your Denon can let you avoid this.

You can pickup an additional pair of A150's on eBay currently for less than a $100, if you want to keep things balanced and even. You'll probably have enough amp to drive 4 of these plus a center (your TV speaker, if that's what you like), if your room isn't too big, and your tastes don't run to loud metal music.
posted by paulsc at 1:02 PM on September 10, 2006

BonusExtraCredit: Does 5.1 improve the audio (as in CD, Music, no video) experience as well? I understand it does this for video, I'm suspicious the techniques used there might not be helpful for audio...
posted by daver at 1:03 PM on September 10, 2006

If by "improve," you mean fake up something to send to the back channels from "ghost" phase information never intentionally recorded or processed for such reproduction in the original stereo recording, sure, 5.1 systems are big improvement. :-)
posted by paulsc at 1:07 PM on September 10, 2006

A few CDs are actually encoded in Dolby Surround and of course there's also DVD-Audio, which is generally 5.1.
posted by kindall at 1:16 PM on September 10, 2006