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Old 29th September 2008, 04:15 PM   #21
GM is offline GM  United States
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Old 30th September 2008, 06:01 PM   #22
defwing is offline defwing  New Zealand
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Thanks for those inputs, they helped me considerably and pointed out my errors.

I have come up with the specifications and have designed the box on paper/hard drive. To fit in with the cabinet design(something special) it had to change a little and I am sure it will change again slightly while building it too

Thanks for your help and I will post pictures when it is done.

Also, sorry to hijack the original thread.
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Old 5th October 2008, 05:09 PM   #23
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Can I get some opinions from people who actually know how to calculate speaker output (unlike me!), I'm wondering if dumping this 2x 12" Type-R setup and replacing it with one 15" Dayton either Reference or Titanic would put out more SPL? Also, how would the responses compare.
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Old 5th October 2008, 09:01 PM   #24
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Default calculating output

Quote:
Originally posted by MattODoom
Can I get some opinions from people who actually know how to calculate speaker output (unlike me!), I'm wondering if dumping this 2x 12" Type-R setup and replacing it with one 15" Dayton either Reference or Titanic would put out more SPL? Also, how would the responses compare.

Calculating speaker output is called a decibel log. dB logs are simple. Let's say the speaker's sensitivity is 93dB@1w/1m, and you have a true 600w of power for this one speaker. every time you double your power starting a 1 watt, you gain 3dB. so 2w=96dB, 4w=99dB, 8w=102dB, 16w=105dB, 32w=108dB, 64w=111dB, 128=114dB, 256w=117dB, 512w=120dB=hearing damage, and the extra 88w that were not added in might gain you 1dB. If you have 2 speakers you add 6dB every time you double power.

In my personal opinion I would go with 1 15" over 2 12" due to the lower frequencies the 15" can produce, and most of the time will achieve higher SPL levels as well.
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Old 5th October 2008, 09:17 PM   #25
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Default Re: calculating output

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Originally posted by TravisDigital



Calculating speaker output is called a decibel log. dB logs are simple. Let's say the speaker's sensitivity is 93dB@1w/1m, and you have a true 600w of power for this one speaker. every time you double your power starting a 1 watt, you gain 3dB. so 2w=96dB, 4w=99dB, 8w=102dB, 16w=105dB, 32w=108dB, 64w=111dB, 128=114dB, 256w=117dB, 512w=120dB=hearing damage, and the extra 88w that were not added in might gain you 1dB. If you have 2 speakers you add 6dB every time you double power.
That's right, but you also have to consider power compression - more current = higher voice coil temperature = higher resistance = less power (P=Iˇ2/R). Typically power compression at full power is approx. 3...6 dB.
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Old 5th October 2008, 11:35 PM   #26
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Default Re: Re: calculating output

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Originally posted by technofreak


That's right, but you also have to consider power compression - more current = higher voice coil temperature = higher resistance = less power (P=IÇ2/R). Typically power compression at full power is approx. 3...6 dB.

yup... you got me, I forgot all about thermal compression. Thanks for posting the formula (p=IC2/R)
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Old 28th December 2013, 11:53 PM   #27
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I'm sorry to resurrect a dead thread but I have a 12" alpine type r from same vintage as this thread and a 500 watt plate amp. I have been strongly considering coupling the 2 together in a horn. I have been following the lilmike builds. Specifically the lilwrecker but built scaled down width for a 12 vs 15. It was referenced as a T12 at times. Curious if anyone built this.
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Old 29th December 2013, 05:05 PM   #28
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lilmike here, just have a different user name on this forum.

I never finished the T-12 fold for a number of reasons, the main one being that I wound up with some 15" drivers that I've been working with.

The Alpine Type R 12s I have worked with perform very well. My experience was that they want a larger cabinet, and they want a low tune. I don't have any on hand to work with at the moment, and don't have a lot of free time either.

Last edited by littlemike; 29th December 2013 at 05:33 PM. Reason: typos
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Old 29th December 2013, 09:42 PM   #29
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Thanks for the reply... I will teach myself hornresp and see what I can come up with. Good knowing that I have pieces that are worth putting together in a tapped horn. Thanks for the response. Hope your time frees up, but you've done a ton of work for the diy community. Rest assured that for every 1 person you reply to, there are another 25-30 people reading and learning. Thanks for all your efforts in removing some of the mysticism of horns. It was not an alignment I would previously have considered without reading your many posts on the subject.
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