8" subwoofer horn
Printed From: Speakerplans.com
Category: Plans
Forum Name: Plan Requests
Forum Description: All plan requests here
URL: https://forum.speakerplans.com/forum_posts.asp?TID=99418
Printed Date: 20 April 2024 at 11:18am
Software Version: Web Wiz Forums 12.06 - https://www.webwizforums.com
Topic: 8" subwoofer horn
Posted By: akadj
Subject: 8" subwoofer horn
Date Posted: 09 October 2017 at 6:09am
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I was looking for a set of plans for a front loaded horn using an 8" Atomic AP8 subwoofer.... I have all the t/s. I wanted Something that would really only just play loud from 50hz to 60hz. "Peaky" if that's what you call it, and it has to be within that range. Something that has a straight taped flare like a trombone. I have a lathe and CNC so it will be super easy and would be a cool project  I don't know how to calculate the tuning for the throat,straight axis,and mouth to tune between 50Hz - 60hz Any help would be appreciated. Thanks, |
Replies:
Posted By: djeddie
Date Posted: 09 October 2017 at 8:42pm
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Well, using 50Hz, for 1/4 length you'll be looking at just under 1.5m and for full length it would be 6m! Best thing is to download a copy of HornResp (Google it, it's free), put the T/S params in and go from there. ------------- Chas n Dave : it's like Drum and Bass but with beards. E=mc² ±3dB |
Posted By: akadj
Date Posted: 10 October 2017 at 3:55am
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I don't have a computer, only a smart phone but don't think hornresp will work on it I.5 meter is pretty much what I was expecting. . . Just not sure about mouth and throat Does anyone have the program and able to plug these in to get me the required dimensions? Thanks |
Posted By: Keen
Date Posted: 10 October 2017 at 6:47am
| post the t/s, someone will get on it for you. |
Posted By: bob4
Date Posted: 10 October 2017 at 10:00am
| Whats the point of 50-60 hz only? Also, this might be easier to realize as a bandpass, if you are absolutely insist on restricting response to that small bandwidth... |
Posted By: akadj
Date Posted: 10 October 2017 at 7:36pm
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Name= ap8.44.new qt motor ww 40 Note= Model= TSL Domain= FreeAir Shape= Round Profile= Cone Fmd= 3.0000 KA Qmd= 1.0000 Flp= 8.0000 KA Qlp= 2.0000 Znom= 4.0000 Ohm Revc= 7.2000 Ohm Sd= 25.0000E-3 M² Mmd= 95.3400 g Pmax= 1.0000E3 W Rtvc= 250.0000E-3 °C/W Xgap= 10.0000E-3 M Xcoil= 40.0000E-3 M Xmax= 15.0000E-3 M Krm= 11.1100 mOhm Erm= 899.0000E-3 Kxm= 280.3000 mH Exm= 530.0000E-3 Rms= 4.3376 N·S/M Mms= 97.6116 g Cms= 128.1486 uM/N Vas= 11.4397 Ltr Fo= 45.0000 Hz Qms= 6.3627 Qes= 0.5359 Qts= 0.4942 BL= 19.2567 T·M Levc= 4.5970E-3 H SPLo= 84.7250 dB No= 186.5000E-3 % I guess I could build an enclosure with the flared straight horn and a bandpass and see which performs the best. that would be fun too!, its only wood and quick to make! the total usable space i have for this 8" is 75cm wide 38cm tall, 100cm in depth
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Posted By: bob4
Date Posted: 11 October 2017 at 6:46am
| is this for some kind of sound effect use? |
Posted By: VECTORDJ
Date Posted: 11 October 2017 at 3:54pm
| Is this one of those fake posts??? |
Posted By: akadj
Date Posted: 11 October 2017 at 4:34pm
no joke guys, just kinda want to get started on these projects, here a photo of the 8" 1500 watt RMS woofers i will be using!
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Posted By: bob4
Date Posted: 11 October 2017 at 6:47pm
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Do you literally intend this loudspeaker to play "from 50 to 60h", or do you mean "from 50 or 60 hz upwards"? |
Posted By: bob4
Date Posted: 11 October 2017 at 6:49pm
| Oh, and looking at the qts of that car audio driver, it is not very suited for horn loading |
Posted By: akadj
Date Posted: 11 October 2017 at 9:43pm
| i will only play in the 50hz to 60hz range |
Posted By: bob4
Date Posted: 12 October 2017 at 5:21am
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oh, I see...... do you care to elaborate how and why you arrived at this design specification? It seems a very odd thing to do. |
Posted By: 4AC
Date Posted: 12 October 2017 at 11:44am
Talking about one note bass  ------------- uǝɿɿɐʌǝ6ɯo sı ʇsʞǝʇ ǝzǝp |
Posted By: Peter Jan
Date Posted: 12 October 2017 at 1:11pm
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With these T/S parameters and the given that you want only solid respons between about 50 to 60 Hz, I would make a 6th order bandpass cab and tune one port around 47-48 Hz and the other port about 63-64 Hz. |
Posted By: DMorison
Date Posted: 12 October 2017 at 4:23pm
I had a hunch when I saw the pic, so a bit of Google-fu shows these are from a brand that specialises in models for car audio competitions - they use specific tone bursts rather than real music, hence only wanting to cover a small frequency range. It also means cabin gain from the vehicle will affect the response and make normal models inaccurate as far as SPL goes. Lastly, a few of the specs seem bogus - they claim it's a 4Ω nominal driver, but Re is 7.2Ω. I've already checked and the maker does not state this is a dual voice coil driver, so we can't even assume the 7.2Ω is for each VC with the 4Ω referring to 2 in parallel. OP also states it's a 1500W driver but the specs posted show Pmax of 1000W, so frankly, I wouldn't trust the specs anyway. Apologies to OP if this comes across a bit negative, best advice I can come up with is find a forum that specialises in car audio rather than this one perhaps? Good Luck, David.
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4AC wrote:Posted By: bass*en*mass
Date Posted: 12 October 2017 at 6:26pm
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i`d second the 6th order bandpass cab option for the required narrow passband.. 1/4wave resonator/transmissionline might be an option too. full frontloaded horn will be too big and wasted imo, bandpasshorn with large front chamber might work though. tbh., that car hifi driver is not ideal to start with.. |
Posted By: akadj
Date Posted: 12 October 2017 at 9:45pm
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So i guess to start with yes, the driver is a dual 4 ohm coil so RE is 7.2 ohms. The woofer has a 2-1/2" flat wound copper coil with dual progressive spiders, trust me they take 1500 watts . The manufacture is one of the oldest manufactures in the USA for audio speakers "SJA INDUSTRIES" so they are very reliable. perhaps they re rated the woofer. I did think about a 6th order series bandpass but thought a horn would be smaller? maybe i'm mistaken... I've been watching some of the videos since i cant run the program, trying to learn about tuning a horn.
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Posted By: akadj
Date Posted: 23 October 2017 at 4:17pm
| ok so i finally got the program installed and have been trying it out. ive never made a horn enclosure before so i'm not sure how big to typical start with, nor do i know where to start tuning. I've built many of regular bass reflux ported boxes. |