HT Receiver pre-out -> power amp?

[desertracer]

I'm researching my first HT system. In fact my main purpose is to listen to stereo music. Of coz we'll watch some movie occasionally with surround. The system will be located in my family room of 18' x 29' x 9'. And the kitchen is located behind the family room on the 18' side.

I looked at couple websites about the required power for the size of this room. Typical HT receiver with 100W/ch is not really enough. So, what I'm thinking is:

DVD/SACD player -> HT Receiver -> Power amp -> Front speakers,
HT Receiver -> Rear speakers, Surround speakers and Sub

With this approach, I don't need to buy a big $$$ multichannel PA, but I still have the capability to watch the multichannel movies.

My question is, only the front speakers go through the external power amp. For 5.1/6.1/7.1 modes, is it going to be a problem for the difference in power going to the speakers (let's say 200W/ch for the fronts, 100W/ch for the rest). I know decent receivers have the auto calibration mode, I bet it won't be able to account for the extra amplification. (may be I'm wrong).

thanks!

 

[annunaki]

You can easily solve your problem with a good, inexpensive spl meter and a setup disc like digital video essentials.

 

[BMXTRIX]

There are a couple of things to consider and one of the main things is the speakers and their size and number of drivers.

When I switched from my Kenwood HTIB speakers (cheap) to Definitive Technology BP-30 speakers, without changing the receiver, the volume output basically doubled or more. It wasn't a power issue, but having some serious speakers feeding the room.

Now, in a 15x20 room with a good A/V receiver there is no way I can turn the volume up more than about halfway without being blown out of the room with just my receiver's amp section.

So, I would not be willing at all to say that the audio won't fill the room for you. It depends much more on what kind of receiver you get and what type of speakers you are using.

If you end up using tiny little speakers then you probably will never be that happy with the audio. But, if you get some good speakers with good drivers - and more than just a couple of drivers - then you will likely be very happy with the sound you get out of your system.

 

[crashguy]

Won't be a problem. You may want to try without buying the external amp 1st, you may not need it. It would depend highly upon the sensitivity of the speakers you choose. I bet you won't need the external amp if you buy a decent A/V receiver.

For the $ you plan to spend on both, you could save some dough by buying a decently powered receiver in the first place. You could always add an amp later if you really think you need it.

 

[gregz]

The smaller receiver + amplifier would be the way to go only if three conditions were met:

1.) Your main speakers are inefficient (< 89 dB)

2.) Your main speakers are full range, carrying your sub frequencies (< 35 Hz)

3.) Your main speakers are high powered (> 150 W each)

If your main speakers aren't going to be the superstars, then I agree that you're better served with a more powerful receiver running the show - and you'll need a GOOD sub to keep up.

 

[desertracer]

Thanks for all the feedback. I guess I really need to nail down the front speakers first. I'm not sure how much power do I need for the room I have. I was thinking about 200W/ch. But with the assumption of Amp(power) > Speaker(power), [otherwise you'll drive the amp into non-linear range to be able to satisfy the speakers]. May be I should back off to 150W/ch or even less.

 

[rschleicher]

Another way to go for a large room is to use horn-loaded speakers for maximum speaker efficiency. Not that you are going to spend $10,000 a pair for speakers, but just for kicks check out Avantgarde's web site. (www.avantgarde-usa.com). I think all of their speakers put out SPLs in excess of 100 dB with a 1 watt input, so 1 W into an Avantgarde speaker is like 100W into a "normal", decently efficient speaker. In their pictures, the horn that looks like the bell of a tuba is actually the mid-range. Their "smaller" speakers use conventional subwoofers in the base, but they also make a "Basshorn" that is a horn-loaded subwoofer that occupies a lot of floorspace, to say the least!

Avantgarde's speakers have gotten a lot of rave reviews in Sterophile. I think the people who buy them are the same ones who buy 5 Wpc single-ended triode tube amps, costing many thousands of dollars.

A more practical approach is to get a set of Klipschhorns, or an old pair of Altec-Lansing "Voice of the Theaters". Both use horn-loading not just for the tweeter, but also for the woofer. As a result, they are both huge boxes, but they are also both very efficient, probably pushing the 100 dB SPL level. Keep in mind that these speakers were designed to fill a commercial movie theater with sound, back when all they had for amplifers were low power tube amps. (certainly well under 100 W).

For that matter, I have an old Victrola that has a horn-loaded cabinet. Volume control is by opening/closing a pair of doors to the wooden horn structure. It provides pretty strong volume from the needle's vibrations, with 0 watts per (one) channel.