My system is too bright - Arcam Alpha 8 + Kef Q900

[theFan]

Hi,

I have a pair of Q900s bi-amped with an Arcam Alpha 8r integraded and Alpha 8 power amp. CD player is Arcam Alpha 8SE.

I've had these speakers for about 6 months now and right from the start i've found them quite bright and a bit harsh. When i turn the volume up a bit (not loud, but a reasonable amount of volume) i get what i call "micro flinches" where i'm kinda flinching on the inside due to the harsh highs. I figured that as i broke in the speakers that some of that brightness would dissappear but it hasn't.

I bought the arcam gear at the same time so i don't have a previous system to compare against but the Arcams are universally known as being laid-back so i'm quite surprised that I'm feeling the way i feel about the highs.

I did find this link where they talk about possible cone break-up or badly designed crossovers:
http://www.diyaudio.com/forums/multi-way/217198-kef-q900-measurements-3.html

Maybe this explains what i'm hearing?

Everyone that listens to my system (non-audiofiles, but i wouldn't call myself an audiofile either) straight away comment on how bright they are.

Maybe because the Arcam gear is so old there is some mainentance i can do on them ie cap replacement?

Can anyone offer a course of action for me to improve the sound?

Cable is stranded figure 8 oxygen free copper, equivalent of AWG14.

Thanks,
Tim

 

[Frank Harvey]

I'll bring this to the attention of Jack at KEF, as he'll be the only one to be able to answer regarding the design.

Do you find the sound changes when you turn them up? Or does the brightness exist at lower frequencies too? Whereabouts is this happening on the volume control - 10 o'clock? 11 o'clock? The Alpha stuff definitely isn't bright or harsh (unless one of them has a problem).

One thing to differentiate - brightness and harshness are quite different things, so for anyone to help, you need to decide which is the more accurate description - although how bright any product can sound is very subjective. Brightness isn't offensive, but harshness is.

Do make sure the HF units haven't been damaged in any way - they shouldn't be as they're protected by a Waveguide, but if they are, this would produce an unpleasant harshness.

Are the speakers placed near to the side walls? Are the bass units working properly? Are the speakers wired in phase?

It could all boil down to the fact that you just don't like the sound of the Q Series - an initial audition might have highlighted this for you.

 

[kevinJ]

It could also be the acoustics of your room messing with the sound.

How is it furnished?

 

[ellisdj]

It could also be the acoustics of your room messing with the sound.

How is it furnished?

That was my best as well - especially as its getting worse as you turn it up...

 

[plastic penguin]

I would guess that it's your amp. The Alpha range produced some smooth-sounding kit, like most Arcs they can struggle if the volume is cranked up. This was the main issue I had my Alpha7 and DIVA amps. Once you go above certain dbs they can lose control a little. The answer is change to a better amp or use a Arcam power amp, assuming you don't wish to part with the Kefs.

 

[theFan]

Thanks for the suggestions. I'm starting to think it's possibly that the sound isn't quite to my tastes but the main reason appears to be the room (it has to be, right?).

The sound i'm getting is definitly "harsh". After 3 minutes of listening (about 1 song) with the volume at 9 o'clock i can feel it in my ears for 20 minutes afterwards - no exageration at all.

They're currently bi-amped with arcam integrated powering the highs, arcam power amp has the low frequencies.

The room is 4 metres by 7 metres with the speakers in the middle of one long wall and the couch against the opposite wall.

This is the only possible arrangement for my lounge because there are double doors and windows going outside at both of the 4 metre sides of the room.

I think the sound must be bouncing off the wall that the couch is against (wall being 10cm from the back of my head when sitting on the couch). Also, because 4 metres isn't a big distance i had the speakers about 15cm from the wall.

I tried putting cushions/rugs against the wall behind the couch to reduce reflections - didn't really make a difference.

I then pulled the speakers well away from the wall and the sound definitly improved but it was still too harsh on my ears.

I tried powering by just the integraded and just the power amp - all i got was a slightly less detailed version of what i had.

When auditioning speakers I wanted some smallish floor-standers that fit the room but could also pump out heavy rock with some authority when needed (Tool, Smashing Pumpkins, Rage Against The Machine).

What I found was that in my price range (500GBP - 1kGBP) as sound quality increased, so did price (understandable) but so did the size of the speaker meaning that to get a decent sound quality i had to get a large speaker than what i really wanted.

In the end i bought the Kefs because they were 250GBP cheaper than MA RX6 and B&W863. I figured they were a well regarded speaker that I could tune my ears to until the first upgrade in a couple of years where my budget would open up a lot more options. What i didn't figure on was that a well regarded speaker could be such a miss-match for my room/amp etc that i can only listen to it at low volumes.

 

[plastic penguin]

Thanks for the suggestions. I'm starting to think it's possibly that the sound isn't quite to my tastes but the main reason appears to be the room (it has to be, right?).

The sound i'm getting is definitly "harsh". After 3 minutes of listening (about 1 song) with the volume at 9 o'clock i can feel it in my ears for 20 minutes afterwards - no exageration at all.

They're currently bi-amped with arcam integrated powering the highs, arcam power amp has the low frequencies.

Okay, try disconnecting the power amp and single wire the speakers.

EDIT - just re-read your post and noticed you've tried the integrated by itself. Something doesn't sound right: I've owned Arcam amps for 17 years and no-way are they bright, unless it's your speakers that aren't matching with the Arcam.

If you look at speakers keep away from monitors with hard tweeters: Monitor Audio, Focal, B&W, Totem... From experience PMC work very well with Arcam and they have soft dome tweeters to boot.

The only other option is to try Nad amp: They are very warm in comparison.

 

[theFan]

It has been about a month since i ran them with just the integraded so i tried it again.

The combination of having the speakers well away from the wall and powered by just the integraded definitly reduced the harshness that i was getting (didn't quite dissappear though). It also made the sound seem a bit distant and not as detailed but at least my ears aren't being assaulted as much so it seems like a good trade-off in the short term.

What i really need to do is:

1. Get a demo pair of RX6s (for example) and compare in my own home.

2. Try my set-up (bi-amp and integrated only) in a much bigger room where everything has room to breath.

 

[plastic penguin]

It has been about a month since i ran them with just the integraded so i tried it again.

The combination of having the speakers well away from the wall and powered by just the integraded definitly reduced the harshness that i was getting (didn't quite dissappear though). It also made the sound seem a bit distant and not as detailed but at least my ears aren't being assaulted as much so it seems like a good trade-off in the short term.

What i really need to do is:

1. Get a demo pair of RX6s (for example) and compare in my own home.

2. Try my set-up (bi-amp and integrated only) in a much bigger room where everything has room to breath.

So is it treble or top-end harness or boomy bass?

 

[ellisdj]

It's the glass causing reflections and probs a peak in the high freqs - glass is a nightmare for it and it sounds like you have a lot of glass. It sounds like glass at each opposing wall so it's reflecting back and fourth and causing the peak

if you can't change your room maybe an equaliser - av amp or standalone such as DSpeaker dual core 2.0 might help.

given what you have said about your room if going the av amp route I would def look at an amp with audessy room correction in it as I think you will need it over Yamaha / pioneers version of the same thing

i personally think www.realtraps.com will have a lot of info for you to read on room acoustics it might help you make some changes that can help.

 

[theFan]

Update:

I've been using these speakers, the Q900, with just the Alpha 8 integrated amp for at least 6 months now and I realised that they weren't harsh in the way i described at the start of this thread. I quite like the sound actually.

I figured that it must have been that the speakers needed a much longer burn-in than what i first thought. So, i re-connected the Alpha 8 power amp. Integreated amp on treble duty, and power amp on the bass frequencies (bi-amp config).

Immediately the harsheness was there again. My wife said she could feel the inside of her ears vibrating and it hurt my ears enough that after one song with volume at about 8:30 my ears hurt for the next hour.

So, it wasn't that the speakers needed more burn-in time.

I then swapped the speaker cables and put the integrated on the bass and the power amp on treble. With this config the harshness is basically gone - i still feel like it's right on the boarder, but my ears didn't hurt.

To me this means that either the Arcam integraded is in need of repair or the amp itself needs more of a load than what the tweeters of the Q900 are providing. Perhaps this amp would perform better with less sensitive speakers.

Any thoughts on what my next move should be?

 

[altruistic.lemon]

I heard your speakers a while ago with a couple of different amps. I found the speakers always a bit too bright, so I don't think an amp change is going to help much.

If you can, have a listen to something like Spendor or neat with your amps, and see how that shapes up.

 

[gasolin]

Change the arcam 8r to a preamp and use the power amp, a more powerfull amp is not likely to reach the levels where it sound harsh as soon as a small amplifier and can often control a speaker better ten a small integrated amp

As i thought kef Q900 has low impedance:

The speaker's impedance is specified as 8 ohms, but as fig.1 shows, the impedance drops to 4 ohms in the top octaves and to below 4 ohms in the lower midrange, reaching a minimum value of 3.17 ohms at 160Hz. There is also a combination of 5 ohms magnitude and –42° electrical phase angle at 80Hz, meaning that the KEF does need to be used with a good 4 ohm–rated amplifier or receiver.

http://www.stereophile.com/content/kef-q900-loudspeaker-measurements

 

[Dougal1331]

Hi,

I had a similar problem with biamp setup a few years ago.

Perhaps the power amp's input sensitivity has slipped out a bit- sounds to me like the power amp is running a dB or two down from the intergrated amp. This is usually adjusted from small variable resistors on the PCB.

I'd say take them to a professional service centre, and ask them to check the input gain. Ideally, they would feed a set, arbitrary signal into the integrated, and test the outputs to ensure exactly the same level from each power section.

Recapping the Arcams may help, but I'd get the input gains checked first!