[thomaspf]

Hi,

I just read an interesting discusison on a seperate forum on the voicing of monitor speakers. From what I understand, the nicely measured frequency response curves only sound correct to a human ear for a given speaker at a specific reference level that the speaker designer picked due to loudness perception.

The argument is, that you can't make a speaker that sounds correct at 80db and 100db SPL at the same time unless you do some form of correction.

This very much concurs with my personal experience that my setup does not sound correct unless I reach a certain sound pressure level. Around 75-80db for my Harbeth Monitor 40.


This makes me wonder whether we could get a loudness corrected digital volume mode from Bryston. I would think this should not be too hard to do and would bring great value if listening at lower than reference levels. Why has no one build this in yet?

I assume you would need the level at which your speakers sound flat as an input parameter and then when you turn the volume down or up the DSP could do the loudness adjustment in the digital domain, maybe just affecting the lower frequencies and leaving the midband alone.

This could simply show up as another surround mode similar to passthrough.

In the evening I always have to resort to headphones and this would allow me to enjoy my system at lower levels without the perceived loss of full frequency reproduction.

James, given your past answers on this forum I suspect you will ask your digital engineer about this .....

Any chance of actually posting his responses


Cheers

    Thomas

[James Tanner]

Hi Thomas,

We do not have any plans to do a loudness compensation on the SP1.7 but your comments about speakers sounding different at different levels is certainly valid.
As a matter of fact that is why I am a big Transmissionline Speaker fan. Due to the loading transmissionline speakers use it maintaines the same dynamic capability throughout it's usable range. That is why PMC speakers have become so popular at the professional studio level because the recording engineer can sit all day at low/mid/hi listening levels and still hear the full dynamics in the playback.

james

[thomaspf]

Hi James

thanks for the reply.

Are you saying that the PMC speakers are somehow doing the loudness correction in the speaker? How are you raising the low frequency output at lower levels. I do understand that you can make a speaker measure flat through a certain operating range, and for transmission line speakers this range might be larger, but how do you compensate for the difference in human perception at different SPL levels.

Cheers

    Thomas

[1oldguy]

Interesting subject to say the least.Wondering if those with more experience than I,which would be most of you   could chime in.

[Phil A]

Here's the basic theory on how a transmission line speaker works:

http://en.wikipedia.org/wiki/Acoustic_transmission_lines

[1oldguy]

Thanks Phil...I shall give it a read in the morning.

[smk]

Do a search for "variable loudness & audio on Google.

[doug s.]

thomas, if your preamp has a dedicated tape loop, you can run a quality equalizer thru it, and set it to what sounds good to you.  that way, you can engage it only when you want, and it will be out of the signal path when the tape loop is not engaged...

doug s.

[Jeffr1966]

the Dynamic Room Correction principle applied in the Tact amplifiers and Lyngdorf amplifiers is designed to compensate for this exact thing ... never heard either amp with DRC though so I cannot vouch for the effectiveness

[1oldguy]

I figure that like my Guitar amp that a home audio speaker(s) need to be driven at least a certain volume to give you the sweet spot.This may or not be true,again I've not a whole lot of experience to go on , more logic than anything and the effect of using the guitar amp.The great thing about the new Bryston Squared Power Curve that at least the amp gives all it's Glory at a much lower volume,so it kind of compensates to a degree.It will be interesting to hear it in action.