110 test tones are way better than 31

Jack from Indo

Puzzled by the small sampling of test tones available elsewhere, I have recently done what seemed obvious to me: I made a test tone of every musical note on the piano keyboard, with a few extra on the top and bottom end, thus giving me a test tone set of Over 100 tones, ranging from 15.44 Hz to 8370.81 Hz. for a total of 110 different test tones.

This far more useful than your standard 31 test tones, (or less). After all, we audio enthusiasts are listening to music, played on musical instruments, with a range of notes roughly equivalent to a piano keyboards range. We are not listening to a 31 band graphic equalizer! Considering that, knowing how your system reacts to every note instead of just a sprinkling of frequencies seems to be an obvious thing to explore, no?

Personally, I do not see how one can really tune one’s system without such a methodical note by note check, because only this many test tones will give you the wide variety needed to represent the music you listen to, and thus really hear and accurately set your crossover points, your resonant frequencies, at et all.

So far, what I have discovered in my own system is interesting indeed, with numerous surprises and I may report later on what I have found and how I corrected it. In the meantime I encourage anyone to do this. It’s easy by using the free test tone generator at http://www.nch.com.au/tonegen/index.html

Generate the following sequence of notes, in hertz, and save them as a wave file. It will take you a while but it is worth it. These notes start at a very low B and go up the musical scale chromatically to a very high C note. Each tone I made lasts for 2 seconds, and they are used by listening to them in sequence, one by one, from the lowest to the highest. Here ya go:




15.44
16.35
17.33
18.36
19.45
20.61
21.83
23.13
24.50
25.96
27.50
29.14
30.87
32.71
34.65
36.71
38.90
41.21
43.66
46.25
49.01
51.92
55.01
58.28
61.74
65.41
69.30
73.42
77.79
82.41
87.31
92.51
98.01
103.83
110.01
116.55
123.48
130.82
138.60
146.84
155.57
164.82
174.62
185.01
196.01
207.66
220.01
233.09
246.95
261.63
277.19
293.67
311.13
329.63
349.23
370.00
392.00
415.31
440.00
466.16
493.88
523.25
554.36
587.32
622.25
659.24
698.44
739.97
783.97
830.59
879.97
932.30
987.73
1046.46
1108.68
1174.61
1244.45
1318.44
1396.84
1479.89
1567.89
1661.11
1759.88
1864.53
1975.39
2092.85
2217.29
2349.13
2488.81
2636.79
2793.58
2959.68
3135.67
3322.11
3519.65
3728.92
3950.64
4185.55
4434.42
4698.09
4977.44
5273.40
5586.96
5919.16
6271.11
6643.99
7039.04
7457.58
7901.01
8370.81

McLoki

Here is a list of test tones you can use to sample your bass. (it only goes up to about 200hz.) They are all recorded at the same volume so you can graph them and see what the room is doing to your bass.

(if you use a radio shack SPL meter - dont forget to put in the corrections for low bass frequencies...)

Michael

Edit - there are about 131 or so....

dorokusai

That's really neat and let me know when you complete your room correction next year. If you start splitting signal into ad nauseum, for test tones in a typical audio enviroment, you will get nowhere. The closer you get, the more interaction they have with one another within the same bandwidth and the levels can vary wildly.

You should send your employment application to www.dolby.com, perhaps they haven't figured this out yet.

I would love to see the time spent on correcting in-car response based on 110 differentials with the same results as those spent on 31. And to nip this in the butt, no, I'm not really interested.

Kudos for the effort, piano rulez and rock on Jack!

MacLeod

Wow! Thats a lot of tones.

Nothing wrong with that but I think youre fine tuning just a wee too much.

The reason there are usually only 31 test tones is that EQ's are at most 1/3 octave so the 31 tones match up exactly with the EQ.

Plus, RTA's are at most 1/3 octave so youd have to use a handheld SPL meter to measure the volume of each tone.....and then you wouldnt be able to tune them really. The 1/3 octave EQ goes from 1.2K to 1.6K so that leaves a lot of those tones out of reach. Plus the bandwidth of the EQ would have to be crazy narrow to be able to tune 1108 and 1174 Hz independantly of each other.

Im with ya on trying to come up with better ways to tune but I think this one is a little much, especially in a car. 1/3 octave is the best, most practical way to go about it.

Jack from Indo

McLeod you are very right that this is too much fine tuning - as you said there's no EQ (that I've heard of) that will allow you that many corrections anyway.

But despite that, there is an educational value in this. As you go up through the notes, there are very noticeable differences in the tonal quality on certain notes as opposed to others, that are not on the recording. (I determined this by first listening to the tones on a pair of Etymotic Research earphones.)

These differences must be coming from reflections and other reasons that are specific to only that frequency.

What practical value is all this? I don't know, maybe none! But it is an interesting exercise to go through.

PolkThug

d00d, just do a sweep.

Jack from Indo

A sweep goes by too quickly. Individual tones, each lasting 2 seconds, is better.
You have tine to individually judge each one. You can then look at your display screen and immediately know which are problematic. A sweep will not do that for you.

PoweredByDodge

I've been using the NCH generator for about 7 years now... first time i tried it was under windows 95... so that's a dead giveaway.

it's a great little tool, simple as all hell and does the job.

the last cd i've been using, titled, "Oz's Shack -O- Tracks: Bumps, Thumps, and Whistles, Vol. 3" spanned 10 Hz to 20k Hz in half octave steps ... 10, 15, 22.5, etc... was a royal pain in the **** to do... but it's been decent to me.