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Why does it sound better at lower volumes?

Hi, I have a Krell, a Slim Devices Transporter, and Aerial 7B speakers with Zu spekaer and ICs. The thing is this combination sounds fantastic, among the best systems I've ever heard at lower even moderate volume levels. The Krell volume control is incremented from 0-150. Anything less than 50 sounds sounds fantastic across the frequency spectrum. But when I go higher on many pieces the highs take on on a harshness that is like an axe chopping broken glass.

Don't get me wrong - a number of pieces sound great - often classical and even some rock such as Fleetwood Mac sound great. I'm trying to figure out if many of the newer i.e., last 20 years, recordings with compression and boosted highs are the problem. Is my system just too good reproducing the dreck out of studios these days?

I've noticed in the car many of the same recordings sound ok with the background noise competing with the boosted highs. They boosted highs are still there but aren't as annoying due to the road noise and limitations of the car stereo.

I've just purchased a balanced cable - the Transporter has native XLR and it's often said Krell sounds noticeably better with XLR. It hasn't arrived yet.

Secondly, I'm thinking about a power conditioner. The guy at the Cable Co. said my system is just very detailed and probably needs power conditioning. Interestingly he wasn't pushing a cable at all.

I live in a new house but the power source isn't discrete. I can wire a discrete one but don't really want to go to the trouble. I have a discrete source in the crawlspace powering a single bulb down there and one outlet. I'm thinking about running an extension cable from that to my system just to try a discrete run to see if I should go further down that road.

Lastly I'm thinking about changing amps. Again is the Krell too good for my own good? :) I've heard a lot of amps from the big and small names and I like the Krell. It simply sounds fantastic... on probably 20% of my music. But I'm starting to think maybe I don't need that 20% like I need the other 80%. :) Maybe some coloration and rolling off of the highs is better at the end of the day.

I have a Sqeezebox as well and have A-B'ed it against my Rega Apollo. The Apollo was a little better but the SB did pretty well against it. I moved on up to the Transporter but haven't A-B'ed it against the Rega.

I've got to do something here, I guess other than listening at lower volumes. I may try a new integrated, say, a Plinius, MF, or go to tubes. Problem with tubes, my speakers aren't efficient so I'd need to eventually change speakers if I go that route. I have recently heard a Manley Stingray on Spendors and Quads and the sound did have that certain ineffable quality of warmth and a good sound. Also same with an SLI-80 and Theils. OTOH, I've heard my 7Bs sound fantastic on other systems such as Theta.

Any thoughts on this conundrum would appreciated. At 46 years old maybe it's just my ears acting their age.

regards, David
wireless200
atmasphere's avatar
atmasphere
12,003 posts
 
If the problem is volume related, either your room is getting over-driven at higher volumes or physical vibration is upsetting your front-end. The latter can be solved by proper equipment stands and anti-vibration platforms- probably for the signal sources (transport) and the preamp.

For the room, diffusion devices are helpful. You might try clapping your hands in the room and seeing if you have any slap echo. Large windows, flat bare walls parallel to each others are anathema at higher volumes!
stevecham
3,340 posts
 
Speaker placement. Try aiming your speakers straight ahead for higher volumes, this should remove some of the beaming that you translate as harshness. I believe that a little drop off to the sides (off axis) can actually help tune speakers for higher listening levels. Also the bass should come back up.
spectron
130 posts
 
There are two potential technical explanations.

1- Most of the power amplifiers increase their level of distortion with output. You can look manufacturer's web site for specs. Many of them gives distortion level at outputs of about 10 watts (and 1 kHz frequency). Some, on other hand, provide distortions level at full output.

2- Many audiophiles pay too much attention at continuous power (rms) values whereas at normal listening levels you need may be 10% of that. On the other hand during the peaks like crescendo you power needs may go up a few hundred times. Pay attention to the following three specs:
a) peak power - self explanatory
b) duration of the peak power - if peak power can be hold for very short period of time, say 20 msec - you will not hear it
c) peak voltage - many power amplifier have it at about 65 volts but if you measure peak voltage from the recording, directly, frequently it will be more then 100 volts

This may lead to clipping, soft or hard.

Additionally, you may have room acoustic and/or other interactions which became highly noticeable with power output.

Simon
spectron
130 posts
 
There are two simle technical explanations.

1- Most of the power amplifiers increase their level of distortion with output. You can look manufacturer's web site for specs. Most of them gives distortion level at outputs of about 10 watts (and 1 kHz frequency). Some, on other hand, provide distortions level at full output.

2- many audiophiles pay much attention at continious power (rms) wheras al normal listening levels you may need may be 10% of that. On other hand during the chrescenso you power needs may go up a few hundred times. Pay attention to the following three specs
a) peak power - self explanantory
b) duration of the peak power - if peak power can be hold for very short period of time, say 20 msec - you will not hear it
c) peak voltage - many power amplifier have it at about 65 volts but if you measure peak voltage from the recording, directly, frequntly it will be more then 100 volts

Additionally, yoi may have room acoustic and/or other ineractions which became noticable with power output.

Simon
oregon
829 posts
 
I can't really say what's going on. Luckily many folks are willing to help.
Here's my take on it:
The amps are the problem, or it could be the speakers. (Although I've never heard either one you mention). But, I have a propensity for the tube "sound". Several tube amos have visited my room, and a few SS amps too. Twice I tried much more powerful amps (than my tubes), one a BAT and recently a Pass 250.5. These amps are indeed powerful and high current, BUT either flat sounding (no soul) and/or lean and grain, especially at moderate to high volume. Most tube amps with decent speakers do not present this problem. Sometimes tubes might be a tad weak and sloppy in the lower frequencies, but, they are listenable and non-fatiguing.
Presently, bass is tight and articulate, not lean. Mids and highs are sweet and natural. I can listen for hours to either CD 20%, or vinyl 80% and even at very high volumes when the groove is on and the fire is lit, it's pure magic.
Good tube mono amps at 30 watts and decent speakers.
This (my experience) does not happen with SS.
FWIW.
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