2x12" Alpine Type-R box

[GM]

Series VCs:

 

[defwing]

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.

 

[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.

 

[TravisDigital]

calculating output

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.

 

[technofreak]

Re: calculating output

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.

 

[TravisDigital]

Re: Re: calculating output

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)

 

[motomark73]

paging GM

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.

 

[littlemike]

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.

 

[motomark73]

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.