15" ported horn
Printed From: Speakerplans.com
Category: Plans
Forum Name: New Projects Forum
Forum Description: Forum for new speakerplans projects, in memory of Tony Wilkes, 1953 - 2014
URL: https://forum.speakerplans.com/forum_posts.asp?TID=40370
Printed Date: 26 March 2026 at 7:42pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: 15" ported horn
Posted By: snowflake
Subject: 15" ported horn
Date Posted: 21 June 2010 at 5:57pm
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Hi just finished building the first prototype of this project. it is 70cm deep 57cm*57cm mouth. driver faces back of the cab where there is an access hatch with a phase plug attached. horn path goes round 90 degree bend and then straight to the front. chamber for driver is in the middle of the box with vents entering horn path about 15cm from the mouth. it was designed to cover 70Hz to 320Hz. sounds pretty good compared to double 15" vented cab. got similar output with ultradrive set 2-3db lower for the horn. as the horn was 8ohm and the vented box 4ohm this makes it 5-6dB more sensitive as predicted by hornresp. sounded a bit faster and more defined - was able to pick out some detail on basslines that was just a constant drone on the vented cab. tried some vocal stuff through it and it sounded no worse than the vented cab. cone excursion was at least half for the same output. as I have recently lost my microphone, laptop and camera phone to thieving ***** can't give any accurate info at this stage - perhaps if anyone in Bristol is interested they might come and measure it and help me tune the ports for a few beers??? cheers Phil |
Replies:
Posted By: darkmatter
Date Posted: 27 June 2010 at 2:56pm
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Very interested to see this as I need something similar. I wasn't sure whether to port it to 70hz or use a longer standard FLH and aim for 80hz. My only worry was that the port might make integration with subs harder. Did you do the driver cutout slightly smaller than the 15" or did you leave the edges of the cone exposed and get the compression from the phase plug? sorry to hear about the robbing bastads! |
Posted By: snowflake
Date Posted: 25 September 2010 at 12:38pm
Here are some screenshots from HR   HR can't model it exactly as the port re-enters the horn 12cm inside the mouth. the path difference is accounted for but not the changed loading on the port. exporting to akabak this is easily adjusted for and shows the bass response going about 5Hz lower. using the directivity tool in HR shows the on axis response much smoother from 400Hz to 700Hz and pretty flat up to 1kHZ. akabak shows similar response up high. |
Posted By: Teunos
Date Posted: 25 September 2010 at 1:31pm
5-6db more sensitive? now that's something strange. a difference of 1 or 2db is possible, but no way the actual horn will be 5-6db more efficient than the hornresp sim.
Will it be used to 320Hz? i think it should be possible (if you used a reversed dome shape phase plug on the top hatch at which the woofer faces) but would like to know how it sounds. Pretty interesting.  ------------- Best regards, Teun. |
snowflake wrote:Posted By: snowflake
Date Posted: 26 September 2010 at 12:55am
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"5-6db more sensitive?"
I mean that as one box was 4R and one 8R the 2-3 dB difference on the ultradrive was in reality a 5-6dB difference in 1W sensitivity between the two boxes - which agrees with the hornresp predictions.
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Posted By: Teunos
Date Posted: 26 September 2010 at 10:20am
Ok, Sorry, my bad  ------------- Best regards, Teun. |
Posted By: snowflake
Date Posted: 01 October 2010 at 11:58am
This is a photo from St Pauls carnvial. there are two unpainted boxes stacked in the middle. mirror man head is removable!
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Posted By: Disco Stu
Date Posted: 01 October 2010 at 3:40pm
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EDIT WRONG THREAD SORRY!
------------- All you need to know is: Sensitivity + Power Handling - Power Compression = Max Output My acts: www.myspace.com/thebowiexperience www.myspace.com/scheisseelektronisches |
Posted By: JD01
Date Posted: 02 October 2010 at 7:53pm
| Why did you vent that horn? |
Posted By: _djk_
Date Posted: 03 October 2010 at 3:19am
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Do you have any idea how much mouth area a 40hz horn requires? Horns with less than optimum mouth area benefit from venting. ------------- djk |
Posted By: JD01
Date Posted: 03 October 2010 at 4:40am
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We are talking about a 70Hz horn, I guess it's used as a "kick cab". Porting such a horn is nonsense IMO, only plausible if the subwoofer below that is a bandpas. Besides, a long horn does not need to have much mouth area as the quarter wave resonance will give some output around 40-50Hz. When stacking them, the effect will wear off and make way for "real" horn output. Works well with my selfmade horns... |
Posted By: _djk_
Date Posted: 03 October 2010 at 10:03am
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. ------------- djk |
Posted By: snowflake
Date Posted: 03 October 2010 at 10:14am
| as djk says to reduce mouth size and make it usable in singles. also to reduce the horn length and minimise the amount of folding to get it into a reasonable depth box. it's 70cm deep the same as my subs and only one 90 degree bend at the start of the horn. hopefully phase plug and symetrical loading of the cone will help reduce distortion. |
Posted By: darkmatter
Date Posted: 03 October 2010 at 2:27pm
Looks good I don't think porting this horn is a nonsense. Yes it might create some integration problems, but how else do you reach that SPL in that size box with a single cab/driver?
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Posted By: snowflake
Date Posted: 05 October 2010 at 12:45pm
here are the plans
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Posted By: Ibex
Date Posted: 05 October 2010 at 12:54pm
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What drivers do you recommend? Do you have a simulated or better a measured response plot of these kick cabs? Very compact design! Would it be possible to leave the last horn mouth section to make it even more compact? |
Posted By: bitzo
Date Posted: 05 October 2010 at 1:26pm
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so the porting fire inside the horn?
------------- http://www.unitedroots.it - United Roots SoundSystem site |
Posted By: snowflake
Date Posted: 05 October 2010 at 4:15pm
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is designed for 18sound 15NLW9400 but have loaded them with the 15ND930 at the moment as I had a pair of those lying around. eventually will have the 15NLW9400 in my tapped subs, in these kick horns, and as the bass in full range tops/monitors. can't shorten the horn any more without reducing the low end. was quite tricky getting the rear chamber length, port length and horn length to work together and give a flatish simulated response. hoping someone is interested enough to help me do some acurate measurements as I don't have a laptop or a decent mic any more and can't find my signal generator.
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