$325 Lab 12 based PA tapped horn ~ 35Hz extension

Hi Y'all,

Let's not get too excited, as I said in Post #451:... 1W into Re the SPL curves are almost identical...

Oliver, Ok so it appears there is no real advantage in using a 21SW152-4 which cost a lot more money over an 18SW115-4 which cost a lot less. For a moment, I thought we had struck gold.:)


I'm done w/ the basic drawing update, but have not had time to do anything else. I decided against reducing the depth, so it will stay @ D=31.875". So the box will be 42x24x31-7/8". It would theoretically be possible to reduce the cross-sectional areas of the horn, and save a little depth, etc. but everytime you reduce the box size you loose some SPL (or low end extension) so I think this is it. I start adding individual board locations/dimensions, hopefully I'll post these later, or tomorrow.

Regards,

The size of the box is OK for me. Thanks much for all your help and those detailed diagrams do did. I am going to play around with Hornresp. Still having issues with the txt file. I plan on building this soon. My plan is to build a normal keystone also and then do a comparison.
 
Hi Scientific,

I cannot evaluate what the difference between the 18SW115 and the 21SW152 will be, there is a minor difference in the curves, the 21" being a little flatter. There is also the increased compression going from 18" to 21" w/o changing S2. I think the 21" can handle the added compression, and more power in general, but I don't know that for sure. My personal choice would be the 18", as Art has reported great results w/ this driver. All those are points you'll have to evaluate during your prototyping. That's why Art spends so much time building and measuring.

Can you tell us what the issues w/ the text file are? Just to make sure, I just tried the MOD#4_21.txt file from Post #455 again:

1. Right click on the file in Post #455 - Save target as
2. Save into the Hornresp/Import file folder (you can change the name while doing that, e.g.: Scn#4_21.txt)
3. Open Hornresp.
4. Click File - Import - Hornresp Record - pick the record name you want to import, and click Open
5. Your Hornresp screen should now show the record w/ the Comment line saying: Art's......MOD#4_21SW152.

I did this twice: before and after updating Hornresp. The newest version is Version 3920-150609, and it works. Tested on a laptop using XP SP3.

Good luck w/ your build.

Regards,
 
How much worth does the HR Impulse Response screen have when designing subs? Am I understanding correctly that is should look like a smooth sine wave, up & down, the closer to 1/-1, the better? What does the peak signify if it happens at 0 vs the dip happening at 0?

I've attached HR screen shots showing the Impulse Response of the PAL12 & MOD4, along with some known builds (i.e. Othorn, Keystone & SS15) below. Are the first plots more favorable and the latter plots less favorable?

Cheers
 

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  • TH 18 18SW115 7800, 1400.JPG
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  • IR Lab 12 4ohm.JPG
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Very interesting question!
Here is the impulse response for a PAL12 with Ciare 12.00SW woofer, to add to your list:

960939_399526353487331_183920063_n.jpg


Someone that has a lot more knowledge&experience about audio (and designing/developing speakers) than me, had a very strong opinion about the design after seeing the IR...

I am curious what others have to say about this.
 
Has anyone else made a pal12 recently? Or made it with a woofer besides the lab12?

I have made 6 pal12 with the labdriver, and it sounded great. But when I heard the 4 LABhorns in a cluster, I just had to build them. Sure, complicated build, heavy as fu*k but sounds awesome, goes really low and high output.

Nothing wrong with the pal12, supernice for dj use, pretty small and light. But for bigger DnB, dubstepgigs the pal12 just won't do

Kevin
 

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So far, the test was carried out without the DSP.
I was very surprised by the sound pressure. Soft and precise bass. Very good construction.
The test was yet to 30W power, but he was knocked furniture.
Today I go for DSP and amplifier.

PS:I apologize for Google Translate