Any benefits with external amp for receiver w/80 Hz x-over? (1 Viewer)

[AndrewKC]

Because bass frequencies are the ones that require the most power, is there any point in getting a separate amp for a receiver if you're going to cross over at 80 Hz anyway? I'm thinking there's not much benefit to be had by spending 2K on a 200 watt 5 channel amp if I let my sub handle the bass. Rather, that money would be better spent on a better sub. Anyone have thoughts on this?

 

[David Judah]

Well, you certainly can't go wrong with a better sub, but as far as the amp is concerned, I think it depends on how big the room is, how difficult of load the speakers present, how sensitive the speakers are, and how close to reference you want to listen at.

Also, you have to consider long term goals as well. If you plan on going to seperates eventually, buying an amp would be a good first stepping stone.

DJ

 

[AndrewKC]

Let's assume the room is big, >5000 cubic feet, and I want to get to reference levels. Say my speakers are of moderate sensitivity, 88 db or so, and nominally 6 ohms. And assume that the receiver has something like 80 watts/channel. My question is if it is possible to measure if the 80 watts will be sufficient to drive the tweeters and mids of a speaker to reference levels once they're relieved of frequencies below 80 Hz or so, despite having speakers that are less than super efficient.

 

[David Judah]

The only way to know for sure is to try it both ways and see if the amp offers a noticaeable improvement under the scenario you describe. Many receivers are woefully deficient in the amp section especially when the impedance starts to drop, but some are decent. All 80 Watt receivers are not created equal, because the manufacturers don't all adhere to the FTC guidelines--IOW, they can play with the numbers.

A good way to compare amps is by using dBW. It gives you a better idea of what the amps can do as the impedance drops, and again its shows that not all amps rated the same, have the same capability. The manufacturers don't usually provide the numbers though, so you'd have to test it yourself which is impractical for most.

It certainly does help a receiver's amp section by using bass management, but under your conditions I'd want to have my bases covered with a dedicated amp. Many receiver's amps start to strain(sound thin and compressed)even before you get near reference level.

DJ