frequency response question

[bkelly]

Most bookshelf speakers have a low end frequency of about 40 to 60 Hz. I just looked up the frequency of middle C and found it is 261.626 Hz. The keyboard next to me goes 3 octaves down from middle C and that is 32.7 Hz. (It goes there more half steps down and plays them just fine.) It has a relatively small speaker and plays that just fine. I definitely want my bookshelf speakers to play that note and several notes below that.

Why do the book shelf speakers, all much larger than the keyboard speaker, stop at significantly higher frequencies? Do they spec the speakers at a 3 db down level?

For about $250 a pair, what frequency should I really expect to be able to hear?

 

[WaynePflughaupt]

Any instrumental note is a rich mixture of the fundamental and multiple overtones. Otherwise every note would sound like a sine wave. You’re primarily hearing the overtones of those bass notes with your keyboard speaker, not the fundamental. Plug the keyboard into a substantial outboard speaker system, such as a PA system or a keyboard amp with a 15” speaker, and you’ll see what I mean.

Ultimately it’s all about physics. A tiny speaker can’t move enough air to generate the fundamentals of ultra-low frequencies. We have subwoofers for a reason, no?

Regards,
Wayne A. Pflughaupt

 

[mtrycrafts]

...

Ultimately it’s all about physics. A tiny speaker can’t move enough air to generate the fundamentals of ultra-low frequencies. We have subwoofers for a reason, no?

Regards,
Wayne A. Pflughaupt

I would think that the movement is there just at a very low level that is not audible or barely, no?

 

[3db]

I would think that the movement is there just at a very low level that is not audible or barely, no?

Yup its there. Ear buds are proof and they are really really tiny

 

[markw]

GOOD speakers specify a frequency range AND a decibel range. this approximates what one can expect in a real-world situation.

i.e. A speaker rated at 40 - 15 hz +/- 3 db will most likely be a better sounding speaker than one rated at simply 40 - 15 kHz. Those frequency extremes could be 10 or even more lower than a 1 kHz tone, which would essentially render them inaudible..

 

[bkelly]

Re: i.e. A speaker rated at 40 - 15 hz +/- 3 db will most likely be a better sounding speaker than one rated at simply 40 - 15 kHz.
Good Point.
I want to spend about $250 for a pair of bookshelf speakers. What do you recommend?

 

[BoredSysAdmin]

since you have a "keyboard next to you" you probably want to get speaker designed to work in same environment - based on my personal experience with JBL lsr2325p, I recommend it's successor model - LSR305 - https://www.massdrop.com/buy/jbl-lsr305 (free signup)

 

[markw]

I want to spend about $250 for a pair of bookshelf speakers. What do you recommend?

My tastes may not reflect yours. I STRONGLY suggest you listen to everything available to you and check out some internet companies like Audio Advisor, Parts Express and accessories4less for starters.

 

[bkelly]

Re: I STRONGLY suggest you listen to everything available....

Good point. The problem is, most places to check out speakers are in a show room, crowded with people, large, and hugely different from the about 11 x 12 foot bedroom, full of junk, where I keep my computer. This is a small town without anything that approaches a high end stereo store.

 

[markw]

There are no guarantees. Sometimes you have to go with your gut feelings and take them home to try. When you buy, either from a store or the internet, be aware of their return policies and keep ALL packing and paperwork.

 

[highfigh]

Most bookshelf speakers have a low end frequency of about 40 to 60 Hz. I just looked up the frequency of middle C and found it is 261.626 Hz. The keyboard next to me goes 3 octaves down from middle C and that is 32.7 Hz. (It goes there more half steps down and plays them just fine.) It has a relatively small speaker and plays that just fine. I definitely want my bookshelf speakers to play that note and several notes below that.

Why do the book shelf speakers, all much larger than the keyboard speaker, stop at significantly higher frequencies? Do they spec the speakers at a 3 db down level?

For about $250 a pair, what frequency should I really expect to be able to hear?

Several factors affect what we hear when a metal string is hammered or plucked. Not only will a fundamental frequency exist, it will also produce overtones, called 'harmonics'. Then, there's the result of placing a speaker near one or more boundaries (floor, wall(s) and ceiling)- the low frequencies are augmented by this and even if the speaker is rated to -3dB @ 42Hz, the perceived and measurable low frequency limit can be as low as ~34Hz. That's very nearly a major 3rd, in musical terms.

Another thing that fools us is the fact that what we "hear" as a deep bass note may be much higher in frequency than we think- a low E on bass guitar has a fundamental of 41.2Hz, but the harmonics are so strong that we don't hear much of that unless the tone controls on the instrument and amp are used to remove the higher frequencies. We're really hearing the octave above the fundamental, or 82.4Hz.

If you place a small speaker in/near a corner, the low end will sound much more full than it would if it were in the middle of the room, or outdoors.