Bi-amping resulting in poorer sound quality

[Dandydandan]

Hi all

A couple of months ago I bought some b&w cm8s. When I purchased them my dealer advised me to try bi-amping the fronts using channel 6 and 7 on my AV amp as he knew that I'm pretty much split 50/50 when it comes to hi-fi and home cinema.

I've just spend the last couple of days comparing and to my ears it sounds worse! I've read various forum posts of people saying they noticed a marginal difference, a big difference no difference at all and some people doubting that it would make a difference. But I've not read anyone else say they had a negative effect.

The amp is a Denon avr1911 and I'm using chord company rumour 2 for all the runs.

Any thoughts? Could it be my amp? In time I was planning on replacing it with one of the recent Arcam AV amps but that might not be for a while.

Cheers, dan

 

[Leeps]

Ultimately you're limited by the single power supply of your AV receiver, so it's not like bi-amping in the true sense of the word unless you start adding power amps to the pre-outs each with their own power supply.

I bi-amp mine but I don't think it makes much difference because I haven't added power amps.

Some speakers, even though they have dual speaker binding posts are recommended not to be bi-amped by the manufacturers for better results, so I guess there are a lot of variables as to whether it improves things or not, but the main one being the quality of the AVR's power supply.

 

[CnoEvil]

Apologies in advance for what may seem like an idiot suggestion...but it has happened before....make sure the amp is set to bi-amp mode, or it sounds much worse.

 

[Dandydandan]

Apologies in advance for what may seem like an idiot suggestion...but it has happened before....make sure the amp is set to bi-amp mode, or it sounds much worse.

ha, thanks. I did make that mistake to begin with!

I should clarify, it doesn't sound bad. It still sounds pretty good, just not as good as when I'm just using the regular outputs. It doesn't sound as focused and the bass isn't as punchy.

 

[MajorFubar]

To be honest, and I realise I'm generalising, I wouldn't bother about bi-amping unless you literally intend to add more boxes, which not too long ago was the only way you could bi-amp: throw more power-amps between the pre-amp/control amp and the speakers. In amps and AVRs with bi-amp modes I think it's little more than a novelty.

Also the meaning of bi-amping seems to have changed. When I first read about it donkey's years ago, people were bridging two identical stereo power amps for mono and using one amp to drive each speaker, so effectively they'd doubled the potential current to each speaker, because current has always been where its at. Then it got to mean using two stereo amps and using one amp to drive the mid and bass and one to drive the tweeter, which IMO is daft because the tweeters need barely a fraction of the current as woofers so the the amp driving the tweeters barely breaks into a sweat unless you play your music at stadium levels.

 

[Leeps]

It doesn't sound as focused and the bass isn't as punchy.

Sometimes even true bi-amping can throw up results that aren't always expected. Sometimes people think, "where has all the bass gone?"

Actually what has happened is that the previously uncontrolled bass is now tighter and better controlled and more in line with what the producers had in mind. Sometimes people assume that more power = more bass, but often the opposite is true.

I'm not saying that's your perception by the way as you seem to indicate that focus is lacking too. More power should provide a more focussed tighter sound.

 

[Nathan]

Ok, REALLY dumb question (so sorry) but did the speaker some with binding blanks between the two reds and two black posts and have you removed them? I only ask because it is possible that I made that mistake once.......

 

[emperor's new clothes]

Hi Dan,

Have you checked mains still set to large and re run Audyssey set up? Sometimes AVRs revert to factory standard after a re configuration. Bi amping works for me as does single wire for the hifi - both QED Ruby evo with airlocks- but much will depend on the passive crossover design and as suggested above, a meaty toroidal transformer. I sold my sub as not required!

 

[manix]

TBH I'm not surprised. You are running £1400 of front LH & RH speakers off a £400 receiver. The chances of it sounding any better trying to use it bi-amp is pretty low. The amp stage in that unit is not going to be great simple cost of electronics components tells you that.