frequency range for instrument vs speaker

Suteetat,

Personally, i find on the majority of my recordings that there is information below 40hz...whether one would care or not is another matter. I find having a sub with a 48db cutoff of anything ABOVE 40hz and the sub continues to work quite a lot during rock bands, electronic (obviously) but even orchestral. Is it 'essential' like midrange? no...but in the overall fullness of sound, i find the sub an integral part of my system i would not do without, and i run Wilson X1/Grand Slamms.

When the kick drums kicks, you can feel the air pressurize. I am not sure that is 'musical information' per se...but it sure feels like an integral part of the experience to me. So does low level info that i often hear within the recording room down at that level on some of my albums.

BTW, i just learned the Bosendorfer piano goes down to 28hz??

Lloyde, I agree with you that there are definitely a lot of information below 40Hz in most music even though the natural fundamental of instruments used do not go below that.
Technically classical music probably have more instruments that can be played with fundamentals down below 40Hz.
So let say, in pop music without synthetizer, the extra information below 40Hz, are those something that is naturally supposed to be there or are there mostly created artificially from EQ or or sound mixer board (in live performance)?

Any full size piano (upright included) would be able to play 28Hz since they all go down to A0. Bosendorfer imperial grand actually has 97 keys instead of the usual 88 keys so officially it will play down to C0 which is about 16Hz. Not that there is that many piano piece that requires anything below A0 except few that Bosendorfer commissioned. I think Bosendorfer believes that these lower keys, even if they are not used directly, will give sympathetic vibration so the piano will sound fuller and more powerful, I think.

>After seeing this link in another thread, I wonder about this. Let say that you don't listen to any classical instrument/music, normal rock and pop with no heavy synthetizer, just drum, guitar, etc, it seems that there isn't really any need for speakers that go much below 40Hz, considering that the lowest instrument, the kick drum (I assume it is the same thing as bass drum?) only go down to 50Hz.

You may still want speakers that play much lower because you need larger drivers for dynamics at higher bass frequencies and the consumer market expects such speakers to have low frequency extension which makes getting one without the other difficult.

Maximum excursion limited SPL from a monopole operating into free space at 1 meter is

102.4dB + 20log(displacement) + 40 log(f) with displacement in m^3

or

102.4dB + 20log(travel) + 20 log(area) with travel in meters an area in meters^2 if you prefer.

Output at the maximum linear excursion into full space for various representative drivers one meter away is as follows at 120, 80, 40, and 20Hz. Many drivers have less excursion and lower output. Subtract 3-5dB getting to your listening position in a typical living and more for a larger space.

You can add 6dB for a floor mounted woofer (as in many 3-ways), 6dB if there are a pair of bass drivers, and 6dB at the cross-over point to a sub-woofer.

Size Driver Sd (cm^2) x xmax (mm) 120Hz 80Hz 40Hz 20Hz
4 1/2" Seas W12CY001 50 x 3 89dB 82dB 70dB 58dB
5 1/4" Peerless 830873 88 x 3.5 95dB 88dB 76dB 64dB
6 1/4" Seas L16RN-SL 104 x 6 101dB 94dB 82dB 70dB
7" Seas W18EX001 126 x 5 102dB 95dB 83dB 71dB
8.5" Seas W22EX001 220 x 5 106dB 99dB 87dB 75dB
10" Peerless 830452 352 x 12.5 118dB 111dB 99dB 87dB
12" Peerless 830500 483 x 12.5 121dB 114dB 102dB 90dB

Where jazz sounds great at 85dBC average and good recordings have 20dB of dynamic range peaks are hitting 105-107dB a meter from each speaker. Feeding _Take Five_ through 60Hz second order Butterworth IIR low-pass filters I noted right channel low frequency peaks 10dB down from that; although that's still 30 times the acoustic power you can squeeze out of a 6" driver at 40Hz.

You may even want sub-woofers in spite of not being a bass-head. They're one way to get displacement past 100Hz without compromising with a larger mid-range that won't mate as well to most conventional dome tweeters. They let you have the SBIR bass null caused by the front wall reflection (at 1130 / 4 / distance in feet which is 70Hz at 4 feet and 57Hz at a more audiophile friendly 5 feet) out of the speakers' pass-bands. Multiple sub-woofers are also an effective way to minimize the big peaks and nulls you get below the room's Schroeder frequency somewhere in the 100-200Hz range for most domestic spaces.

Drew, thanks for your information. I certainly don't disagree that giving bass extension can help to improve midbass performance as well. However, I don't think that it would answer my question regarding playing music that contains fundamentals that are only 50Hz or above as to what kind of sound, information or contents those recording contains that are below 50Hz? I am not trying to pick on recording studio, sound engineer regarding equalization or anything like that but actually try to understand more about what I hear.