This is going to be as boring as most anything technically you've ever read, but here goes. I worked with the Tune Bot tonight for a while and came away with some interesting results. Again I was using my 12" Ludwig Classic Maple rack tom which was already tuned and sounded great. I always use the filter mode because it gets me closer to what I'm hearing than without using it. At first I was holding the tom by its suspension mount, when I hit the center of the head the Tune Bot registered a reading of 107.6 cycles. OK, so about five seconds later I hit it again with a little more force, the reading now registered at 113 cycles.
Next I moved my 12" tom to my work table. I tried both a towel under the opposite head and also without it. I now have the Tune Bot at the 10 o'clock position on the hoop. I usually call tension rod #1 the lug just to the right of the logo on the drum head and the logo is always at the top of the drum. Tension rod #1 gave me a reading of 268 cycles, kinda of weird. #2 was 198.6, #3 was 198.7, #4 was 268.5, #5 was 199.1 and #6 was 198.6. All except tension rods 1 and 4 were pretty close, I was pretty proud of what my ears had done. I started working with rod #1, trying to ascertain why the Tune Bot was registering a semi harmonic instead of the specific fundamental. A true second harmonic would be the doubling of the fundamental frequency. I was hitting one inch behind each tension rod. No matter what I did, I could not get that reading back to the fundamental frequency of the other rods. I brought the tension down on both 1 and 4 and it still read 267 cycles at #1. For grins and giggles, I moved the Tune Bot and placed it at the 12 o'clock position on the hoop, wow, now it's reading 197.1, close to the fundamental frequency at the rest of the drums lugs. OK something is strange here, so I mover the Tune Bot back to the 10 o'clock position and again it's reading 262 cycles. I didn't adjust any tension rods between the times I moved the Tune Bot. The Tune Bot is supposed to be able to accurately read the sound from the head anywhere around the hoop. The tension rods 1 and 4 sounded a bit flat to my ears, but the device was not picking this up as a fundamental frequency, even though the "filter" was in the circuit at the time. I moved the Tune Bot to the 6 o'clock position of the hoop.and hit the area of the #1 tension rod again. The reading was 259.8 cycles, not touching anything, I gave it another hit five or six seconds later, now it was within a couple of cycles of the 2, 3, 5 and 6 tension rods. I was finding some of the readings to be a bit wish washy. I don't want to have to interpret which readings are more accurate than others. This unit is supposed to expedite the tuning process, this has yet to be proven to me.
I was running out of time and I still wanted to experiment with a few other things. I thought that it would be a cool idea to actually learn what frequencies my bass drums were tuned. I used the Tune Bot on the resonant heads of the drums. My 20" Ludwig bass drum registered at 61.5 cycles, OK for a 20" drum. My Gretsch Renown 22" drum had a reading of 51.5 cycles. My Yamaha Maple Custom Absolute 22" bass drum registered at 49.7 cycles, but what was jaw dropping was my Tama Starclassic Bubinga 22" drum, it registered a low 41.6 cycles. You can feel this drum in your chest, lol. My DW drums weren't in the house, so I couldn't check its bass drum. I still don't know the accuracy of these readings, but it was a fun experiment to do.
After again re-touching the tuning on my 12" tom, by ear, I made a log of what the Tune Bot "hears" as the frequency of each drum of the Ludwig Classic Maple kit. The 12 x 8 was 107.9 cycles, the 13 x 9 was 99, the 14 x 14 was 81.9, the 16 x 16 was 72, snare was 190.2 and the bass drum, 61.5 cycles. These were all dead center hits. Again, there was quite a bit of a discrepancy on these reading depending on how hard the head was hit. The harder the hit, the higher the frequency readout on the Tune Bot.
There are some things I like about this unit, but many things I believe could be more refined.
The only way I could get a check on its accuracy is to open the unit and inject a low frequency pulse signal into its audio input stage, I'm not going to do this for obvious reasons, at least not yet. I truly believe the Tune Bot has Too much sensitivity. It shouldn't be so sensitive that a drum hit from over three feet away will find its way into its gate, especially with the device mounted on the drum hoop less than an inch away fro the head. I believe a unit with a variable sensitivity range would make for much more accurate and stable readouts. The Tune Bot definitely has a low pass filter inline, especially with the "filter" switch activated. It seems as if nothing higher in frequency than about 300 to 350 cycles gets through to it. This is good because you really don't need the entire audio spectrum affecting the readings your getting from a "lo fi' frequency sound source of audio such as drums.
This is all I have for now. The next time I have some time on my hands, I'll delve a little farther. I really wish that I had another Tune Bot to check side by side with the one I have. Maybe some of these findings are just inherent with this particular unit. My opinion so far is, that if you have the ability to tune your drums by ear, this unit will not make things better for you in that account. If you can tune by ear and you purchase one of these units, it will probably make you wish that you never heard of Tune Bot because of the shear frustration and time consuming nature of its usage. At least this is the way it affected me. I did find it amusing to be able to "see" the frequency ranges of some of my drums, accurate or not. For people that do not have the ability to tune by ear, it might be just the thing to get you happy with your drums again. I soon have to re-head another set of drums, I'll see if my girlfriend has the time to do it with the assistance of the Tune Bot.
These are just my personal findings and descriptions. 03/07/12
Dennis