Frequency Range and Sounds

Crossovers aren't brick walls, so chances are you'll hear those sounds softer, but they won't be missing (not in a gap that small).

Check out the chart linked below. It's interactive: slide the cursor down the frequency you're interested in and see the descriptions in the boxes to the right side.

http://www.independentrecording.net/irn/resources/freqchart/main_display.htm

Personally, I would set the crossover to 100Hz and not bother with the gap.

Post 2 is correct as far as it goes. As it says the crossovers in our receivers and surround decoders aren't anything like brick walls. So, if there's a small gap between crossover points, there is at worst a slight dip.

Several other things needs to be considered.

(1) In the same frequency range where this dip would be at, is already very rough due to common room deficiencies such as standing waves. The kind of slight dip this mismatch might cause is probably small and innocent compared to other dips that are typically already there due to nature.

(2) Instruments are not restricted to such narrow frequency ranges. Even single notes typically cover a wide frequency range because musical instruments generate sounds that are loaded with harmonics. For example the note F2 has a fundamental frequency of 87 Hz, but depending on which instrument it is being played on, there are also harmonics at 176 Hz and 261 Hz and so on up. In the case of the second harmonic, when the ears hear it, it may tend to create the perception of the fundamental, even if the fundamental were totally missing.


Hearing 35 Khz on anybody's audio system while playing a recording of music is unlikely. Recordings with potentially audible amounts of energy at 35 Khz are extremely unlikey. While recordings made with 96 or 176 Khz sampling rates can potentially record and playback sounds this high, actual recordings with enough energy at this frequency or even just > 20 KHz are very rare. Studies have shown that about half of the DVD-A and SACD recordings that are out there were made from legacy masters that simply don't have significant energy on them > 22 or 24 KHz. Very few of the microphones actually used for producing recordings respond this high. The air has significant additional attenuation of frequencies this high and tends to attenuate them over the usual distances that are involved in listening to concerts or recording them. Finally, the ear has a very significant characteristic called masking wherein stronger sounds, which naturally occur at lower frequencles like say 8-12 KHz, cause the ear to shut down and not respond to frequencies at even 16-20 KHz.

Just for grins,

http://www.seventhstring.com/tuningfork/tuningfork.html allows you to play notes on a virtual keyboard, and the frequency shows up in the upper left hand corner. The fundamentals are from about 63 to 2000 Hz. You can change the sound from a pure sine wave to add more harmonics, turning it into a sawtooth wave or a triangle, I forget. ANyway, on my laptop, notes that are inaudibly deep for the little speakers become audible and identifiable with the added harmonics.

Stereophile editorJohn Atkinson’s posted the spectrum of his Fender Precision playing a low E at http://www.stereophile.com/features/338/index.html. Fundamental right around 40 hz, the second harmonic at 80 Hz is over 10 dB louder. Turns out this is about the way it works with most electric basses, at least anecdotally.

You have to consider that the sound does not "stop" at the crossover freq.

And since most people like to run their subs 'hot", the ACOUSTICAL crossover is higher than the electrical.

how much higher? Depends on how loud you run the subs. It could be as much as an octave (or twice the freq).

So there is no simple answer.

I really doubt you would "miss" anything and I bet many people could not even tell the difference-depending on the situation and the source material-how well the system in question is setup and so forth.

Lots of variables.

That is consistent with my experience on every one of my basses I have measured. The 34" scale of a standard electric bass is not long enough to support a full fundamental at low E, but the 1H comes up quite a lot by A or B depending upon the instrument. Similarly my short scale Alembics measured with a lower 1H/2H ratio and I've seen an electric URB once that was much closer to unity, but I forget the numbers.

The picture is:



I do a lot of recording, and edit with a DAW so I see tons of waves of musical instruments and can get a FFT of them on a whim. That all said its not the least bit uncommon for the harmonics to be louder either individually or taken as a group, than the fundamental. Even many pipe organs do this, and it s not that because are trying to fool people's ears with short pipes.

No human being can hear 35KHz sound, so buying speakers that can reproduce that is pointless. Human hearing tops out around 20KHz.

Yes the true way to tell is to set it and listen to various recordings then set to the other position and listen to the same recordings.
Analyzers and other instruments can give you a nice graphical picture but what really matters is what you hear.

...with the caveat that if you do this the traditional audiophile way, with long (more than a second or two) delays between the listening sessions, the delays themselves will make things sound different and you can easily end up with an extensive and frustrating tail-chasing session.

The reason why we give test equipment even a second look is that it can save a lot of time and frustration if you learn how to properly use it.

In the case of matching speakers with a crossover, I'd be prone to take what the test equipment says very seriously.