In car audio, what is Qtc?

dbzeag

Wants to kiss you where it stinks
Jun 9, 2006
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So I am reassembling my amp.sub box and I was using some online calculators to determine the size of the enclosure. The conversions have a value called Qtc that it needs to size the box.

Anyone know what that is or what it should be or how I can find it?

Thanks
 
In reading some other things, it looks to be a constant. The flattest signal that is the most accurate is 0.707. Is this right? Is this what I should shoot for?
 
Qtc is the total Q of the speaker in an enclosure including all system resistances. A Qtc of .707 is the most common and generally produces the flattest frequency response with approximately a 6dB/octave rolloff. Higher values of Qtc will give a peak in the output with a sharper rolloff. A lower Qtc will start to roll off earlier and will roll off at a slower rate. If you don't know what Qtc you need, start with a Qtc of .707.
 
I say this honestly and sincerely : speaker design is a black art. It is not for the weak of heart. Its some serious mathematics and old fashioned craftsmanship rolled into one. Its easy to get medicore results and very hard to get excellent results. Stick with pre-fabbed boxes or designs.
 
I say this honestly and sincerely : speaker design is a black art. It is not for the weak of heart. Its some serious mathematics and old fashioned craftsmanship rolled into one. Its easy to get medicore results and very hard to get excellent results. Stick with pre-fabbed boxes or designs.

I would, but since I am not actually installing it and just getting measurements for my installer I don't care too much. Maybe I can mix the two together. Just get a prefab box and build off of it.

Know any high quality box makers?
 
I would, but since I am not actually installing it and just getting measurements for my installer I don't care too much. Maybe I can mix the two together. Just get a prefab box and build off of it.

Know any high quality box makers?
Boxes : you can get reasonable price-to-performance stuff from Partsexpress.com.
Guides/plans : go find the Car Stereo Cookbook by Mark Rumrich. Foolproof designs.

This isn't a cop out, but high quality is only defined by how much you're willing to spend. You can seriously go insane on it. I would set a budget and only look at speakers in that range. If you start messing with things above your price level, you'll get envious and try and rationalize a tens-of-thousands of dollars purchase because it sounds like angels singing. Its easy to develop OCD in this field once you know what's possible.
 
I would set a budget and only look at speakers in that range. If you start messing with things above your price level, you'll get envious and try and rationalize a tens-of-thousands of dollars purchase because it sounds like angels singing. Its easy to develop OCD in this field once you know what's possible.

QFT...

I dropped about 5k on my car before I knew it because I was getting shit at cost. There is about 9k in my car at retail price between the tv's, amps, dvd player, hex doors, subs blah blah... My car dropped in value over the years and now I wish I had that money
 
You need one of these if you really want to hear a difference:
:lol::lol::lol:
That has got to be one of the biggest crocks of shit I've ever read. Wow.

Recently I've thought about trying to experiment with this. All you'd really need is a little understanding of Bernoulli and wing design, a good servomotor, controller/waveform generator, and conditioned power supply. No way it should cost more than about $300-$400 tops for that.

I wonder if you could set up several motors of varying size and coupled this device with fluted pipes to make a full range system?
 
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