Live versus home audio bass response

[soundminded]

One thing that often amazes me when I hear live music, whether jazz or orchestral is how much bass it has compared to home audio systems playing "flat". I've often wondered about this. I assume that there are several contributing factors. Most home audio systems have a bass rolloff that is fairly far down by the time it gets to the lowest octave. The low frequency cutoff specification for most speakers has it down 3 db already compared to the 1 khz level and that's in an anechoic chamber. Additionally, the small dimensions of home listening rooms compared to venues for live performance doesn't allow for acoustic reinforcement of bass at home the way the live venues do. In large auditoriums, the much shorter reverberation times at high frequencies compared to low frequencies means that the total energy of low frequencies for each musical note is far greater than for higher frequencies starting at the same loudness level. As a result, to get tonal balance to sound accurate, I've had to equalize the bass substantially even with some of the best performing speakers like AR9 and Bose 901 series 1.

Anybody else have this experience? I am of course referring to unamplified live music. With amplified reinforcement systems of course, all bets are off.

[ninohernes]

A lot has do do with the size of the room. In the summer here, there is a jazz festival which I record and do sound reinforcement. I use two AR-3 speakers (200 watts per channel) in a concert hall that seats about 200. In the larger room, the bass is much more pronounced, because it has space do develop.

Also, hearing a jazz concert live through AR-3's is an experence! So many people came up to me after the concert commenting on how good it sounded.

Also, for unamped live shows that I have recorded, the bass is more prominent, for the same reasons. The sound has space to develop. Remember, concert halls are designed to not use amplification, so they use natural amplification, which enhances bass frequencies. Your living room (or where ever you listen) was not desinged to do this.

[soundminded]

Your experience is consistant with known acoustical facts. It is a fact that large rooms acoustically reinforce bass for a number of reasons. For one, the long dimensions cut the room off acoustically at much lower frequencies. Every room has an acoustical cutoff frequency below which there is no acoustical reinforcement of bass. Rooms we use in homes DO NOT acoustically support deep bass because they are simply too small. Below this cutoff, there is a rapid falloff of bass response due to the room. Another shortcoming of home listening rooms compared to auditoriums is the long reverberation time of low frequencies compared to high frequencies. This time could be double or more making the low frequency reverb tones present the listener with twice as much low frequency energy or more compared to high tones relative to their respective loudnesses generated by the instruments themselves. Then there are the speakers. Loudspeakers, even the most venerated bass reporducers like AR3, AR9, and others have their response begin to fall of well above the lowest limits of hearing, sometimes at 40 hz or more. They are usually down at least 3db and sometimes much more by 30 hz and far more at lower frequencies. Acoustic suspension speakers fall off at 12 db per octave. Ported speakers are much worse having a very very fast fall off with a near vertical drop. Speaker placement in the room may make the low frequencies relatively louder but I don't think they can extend the response if it isn't there in the speaker to begin with.

One thing I've always noticed in live performances of classical music is how loud and deep the sound of plucked cellos and double bases are in many pieces and how much they add to the tone of a symphony orchestra. In most recordings played through most sound systems in a home, you don't even hear them let alone feel them. This is one reason I have thrown measurements of audio equipment out the window and regard the so called "flat" settings of preamplifiers as laughable. The tonal balance of even the best home audio systems is entirely inadequate IMO for a serious attempt at accurate sound reproduction highly contrived live versus recorded demos in the same room notwithstanding. For adjusting the systems I listen to, I use an equalizer and adjust the sound to be as much as I can get it on most recordings I own based on my good but imperfect memory of live music. Even so, it takes a good year or two to come close. Very frustrating requiring a great deal of patience.

[ninohernes]

The flat setting on the preamp does not mean that the signal is at its most natural sounding point, it just means that there is no added or subtracted EQ. I rarely use the tone controls on my preamp, most things sound good in my living room. In my recording studio, on my monitors (AR-2's) I cut the trebble a bit, because I sit so close to them, and I boost the bass a bit for the same reason.