Tapped Horn and Driver resonance Freq. - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 8th April 2009, 04:20 AM   #1
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
Default Tapped Horn and Driver resonance Freq.

Gents, I have not done much in a few years DIY, but it is time…

I have been entering huge amounts of drivers into Hornresp and some give great results. If 1 driver wont come out well, often multiples fix this nicely.

In some instances, what appears to be "optimal" tuning gives the tuning well away from the driver resonance with the impedence peak being right on the drivers resonance freq.

Is this a problem?? Will this give uncontrolled muddy bass at this frequency - overhang etc or will the damping of the amplifier cause this to not exist??

Gents your opinion very much sought since I have found a pair of high quality 10" drivers that in 260 litres and only 500w give an amazing 116db @ 19Hz 2PI!!!! It is xmax limited to 116db at 26Hz also. This suits my application since I only have 500w to play with per side…. So I need to build two of these.

I also have no concept as to how powerful this will be in a 1Pi situation and two of them. Bill Cowan (G'Day Bill), you could probably explain how close this might get to your 4 sealed 12" XXLS drivers per side…….. If this is "too much" I could tune it lower.....
  Reply With Quote
Old 8th April 2009, 04:49 AM   #2
diyAudio Member
 
Join Date: Jul 2008
Location: Pacific Northwest
I'd give it a try. You can always do a proof-of-concept build to make sure it works before you make it look nice - you're only out your time and some MDF or plywood if you're not happy with the results.

As a general rule of thumb, tapped horns seem to perform best when the driver resonance is approximately twice the tuning frequency of the horn.

The tuning I used for the last one I built resulted in an impedance peak near the driver free-air resonance, as well as peaks near resonance/2 and resonance X2.

I can only imagine what two 20 Hz tapped horns would do. My last project (4 Tang Band 6-inch drivers in a 140 L ~30-Hz horn) reached over 120 dB above 25 Hz when installed. We chose not to take it any louder - there was plenty of amplifier and driver excursion left. I rolled it off below 30 Hz at 12 dB/octave to protect the drivers from excessive excursion.

I'm no golden-eared audiophile, but I was pleased with the sound. Bass was tight and very clean. Sounded nicer than the 12" driver in a sealed box that was in use previously. Low frequency effects literally shake things, and the bass has a more tactile feel when turned up.
  Reply With Quote
Old 8th April 2009, 08:10 AM   #3
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
Thanks for the response littlemike,

Some years ago I had the pleasure of getting a tour of Bill Cowans audio endeavours. If I can get near his soffit mounted woofer sound I will be more than pleased. That was effortless in its sound and the low end was so low as to "grip" you.

he showed me the 30Hz TH and it was hooked up to a small sattelite system as the sub. Unfortunately we didnt give it much of a whirl.

Anyways....

I will sim the 6.5" TB sub arrangement and compare to my sim.

I would still like to hear some other responses as to the resonance and tuning issue since I have not commited to the drivers yet so am able to choose something else.
  Reply With Quote
Old 8th April 2009, 02:51 PM   #4
freddi is offline freddi  United States
diyAudio Member
 
freddi's Avatar
 
Join Date: Aug 2005
in some cases driver fs runs ~1/2 octave above horn cutoff -- here's a reverse taper pipe input-Z - fs should be 28 by spec- the path could be made longer and the 1st Z peak's amplitude would dominate -
Click the image to open in full size.

I'm not sure if inverted tap horn (if that's an apt term-?) has a place compared to positive flare = "maybe" (?) half-space half power is around 40 and the 1st Z-minimum around 28 so its well damped around 30 - a good TH might whup it in the same bulk - I built this ~48"x15.25"x17.7" rough test mule after seeing "nineleaves" thread at Speakerplans and its 7.4 cubic foot bulk allows good comparison to a Karlson box. David McBean's hornresp nails its performance
Click the image to open in full size.

indoors but kinda like half-space - I didn't have the leaks sealed well - opening IIRC was ~5.5"x16.25" Fs in this inverted case is ~1/2 octave below cutoff
Click the image to open in full size.
  Reply With Quote
Old 8th April 2009, 05:02 PM   #5
diyAudio Member
 
Join Date: Jul 2008
Location: Pacific Northwest
@ Bent

Which 10-inch drivers are you looking at?

The details of the quad tang-band 6 tapped horn I designed and built are buried in the collaborative thread, but should come up with a search.
  Reply With Quote
Old 9th April 2009, 02:34 AM   #6
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
The Datyon RSS265HO-4 see attached details

Others come up well also, like HiVi M12 and particularly one of the Tang Bad 12" drivers - impressive. But for small box size, this seems to trump all others I simulated.
Attached Images
File Type: jpg clip_image001.jpg (24.3 KB, 885 views)
  Reply With Quote
Old 9th April 2009, 02:35 AM   #7
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
Here is the data and freq response
Attached Images
File Type: jpg clip_image002.jpg (25.5 KB, 874 views)
  Reply With Quote
Old 9th April 2009, 04:23 AM   #8
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
@ Littlemike;

Is it me or does Tang Band make speakers for dedicated TH use??

I just put the 4x W8-1363sb in the same enclosure as your 4xW6 version and blow me down if it isnt a smooth response with way more output. I can hardly believe it - all for 138 litres!! The sensitivity is down as you get to 21hz but impressive anyway!!

Many of the other woofers are the same. I have a blown amp Logitech Z5500 system here that I believe has the WT-644F in it (10", 10mm xmax) and that also models well.

That might be a good starter TH.

The hard thing apparantly about doing a TH is actually deciding the driver - so many model perfectly!
  Reply With Quote
Old 9th April 2009, 05:33 AM   #9
diyAudio Member
 
Join Date: Jul 2008
Location: Pacific Northwest
Only concern I have about the larger drivers in a small box is that the compression ratio (Sd to S2) gets too high. Mine is at just over 3, which may be pushing the envelope a bit. Your sims seem to be running nearer to 4.

Most drivers simulate very well in a tapped horn of some size, the real issues are can the driver fit inside the box, or can the box fit inside the room. When you throw those two criteria at it - the list gets a lot shorter.
  Reply With Quote
Old 9th April 2009, 05:42 AM   #10
Bent is offline Bent  Australia
diyAudio Member
 
Join Date: Jun 2004
Location: Perth, Australia
Thanks for the tip. Actually I had discregarded the S2 for my sims, now that I am usuing it, I have found the good old Peerless XLS 830500 sims really well - as good as the others. It is an expensive (kind of) driver, but I have two already in a powered home sub, so why not build one. ......

The sim I have is for 288L so kind of big, but does 20Hz no problem @ 117db 2PI.......

I currently have them in a 80L ported box with a dayton 1000w plate amp. That really kicks butt (since it is corner loaded). I never painted the box..... so time to rip them out and put them in a TH along with the plate amp.....
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Double Driver Tapped Horn MaVo Subwoofers 28 23rd January 2009 05:38 PM
how to calculate resonance freq in H-baffle bvan Subwoofers 5 14th January 2009 10:52 PM


New To Site? Need Help?

All times are GMT. The time now is 04:46 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2