TH Criteria ? - 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 25th October 2011, 09:31 AM   #1
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
Default TH Criteria ?

Hi all TH fans

Just wondering what you consider the most important specifications a driver requires for a successful TH design ? Apart from Xmax/SPL@1W/Power/Sd

1 - High or low Qm

2 - High or low Qe

3 - Below or above overall Qts of .3

4 - Vas Below or above 300L

Anything else ?

TIA
  Reply With Quote
Old 25th October 2011, 12:18 PM   #2
diyAudio Member
 
Join Date: Jan 2005
Location: Rotterdam, NL
1 - Most driver seem to be in the ~4 - 8 range, not a necessity afaik.

2/3 - Qes/ Qts are ussually quite close, especially in the lower range. Lower Qes drivers often require differerent segment, compression ratio and driver positioning then higher Qes drivers. Traditional (as in Danley's typical) tapped horns are ussually low Qts drivers (lower then 0.3)

4 - Vas is driver diameter related 300 L is average for an 18" PA driver, 200 L average for a 15" PA driver, etc. Overall low(er) Vas is good.

Vas can also be related to Qes in designing a tapped horn. Traditional tapped horns seem to favor both low Vas and Qes. Up to a point higher Vas could be counteracted by very low Qes and vice versa.

5 - Fs = 1.414 x Fc

Taking 2/3 - 4 - 5 in mind (Fs, Qts, Vas) I personally would discard "stated sensitivty" as an important specification.

Danley also stated Mmd/Mms iirc, which would imply high Xmax and large VC.

Best regards Johan
__________________
Impossibilities we do immediatly, miracles take slightly longer.

Last edited by Rademakers; 25th October 2011 at 12:21 PM.
  Reply With Quote
Old 27th October 2011, 01:13 AM   #3
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
@ Rademakers

Hi & thanks for responding

I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !
  Reply With Quote
Old 27th October 2011, 04:45 PM   #4
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by Zero D View Post
@ Rademakers

Hi & thanks for responding

I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !
High Bl is needed.

A well designed TH can be 6 dB more sensitive than a BR, but the load on the cone is also way more.
A very stiff cone is needed to keep distortion reasonable at high power, Hornresp will show light cones with high Bl to be quite high in sensitivity, but when pushed hard the driver will sound distressed before Xmax is reached.

That said, it seems there are many TH builders that don't mind that sound.

Art Welter
  Reply With Quote
Old 28th October 2011, 09:16 PM   #5
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
Hi, thanks for posting

Quote:
Originally Posted by weltersys

High Bl is needed.
I guess that may be only be a prerequisite for designs with high compression ratios in the throat ?

Quote:
Hornresp will show light cones with high Bl to be quite high in sensitivity, but when pushed hard the driver will sound distressed before Xmax is reached
.

So no free lunch then

Quote:
That said, it seems there are many TH builders that don't mind that sound.
Maybe they havn't admitted it, as i don't recall anyone mentioning it
  Reply With Quote
Old 29th October 2011, 12:28 AM   #6
Spuddy is offline Spuddy  United States
diyAudio Member
 
Join Date: Feb 2010
Location: NH
Quote:
Originally Posted by Zero D View Post
Maybe they havn't admitted it, as i don't recall anyone mentioning it
Maybe they can't tell what's happening amid the chaos

I've had my Kraken TH up and running for a week now, and I have no idea how loud it gets or how clean it is, because every time I try upping the volume at 16-18hz my house feels like it's collapsing and I wimp out! Not even kind of exagerating
  Reply With Quote
Old 29th October 2011, 01:52 AM   #7
diyAudio Member
 
Join Date: Jan 2008
Quote:
Originally Posted by Zero D View Post
Hi, thanks for posting
I guess that may be only be a prerequisite for designs with high compression ratios in the throat ?
Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.

The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.
  Reply With Quote
Old 29th October 2011, 02:10 AM   #8
Spuddy is offline Spuddy  United States
diyAudio Member
 
Join Date: Feb 2010
Location: NH
Quote:
Originally Posted by weltersys View Post
Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.

The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.
Sorry if I'm somewhat out of my league here, but would this be the reason some larger horns utilize two drivers set up in a push/pull configuration? If yes, then is that something worth taking into consideration for the criteria of this thread?
  Reply With Quote
Old 29th October 2011, 05:49 AM   #9
Zero D is offline Zero D  United Kingdom
diyAudio Member
 
Join Date: Aug 2009
Quote:
Originally Posted by Spuddy

Maybe they can't tell what's happening amid the chaos


Quote:
I've had my Kraken TH up and running for a week now, and I have no idea how loud it gets or how clean it is, because every time I try upping the volume at 16-18hz my house feels like it's collapsing and I wimp out! Not even kind of exagerating
Sounds good Is that with movies, and/or music ?

Quote:
Sorry if I'm somewhat out of my league here, but would this be the reason some larger horns utilize two drivers set up in a push/pull configuration? If yes, then is that something worth taking into consideration for the criteria of this thread?
Well that would reduce f2 distortion But as in other designs, f2D is often viewed/heard as a bonus !

Quote:
Originally Posted by weltersys

Perhaps, I have not played extensively with low Bl and low compression, but putting a whimpy magnet 10" in a 2.5/1 ratio TH resulted in a response curve that looked like an upside down "V", the worst response I'd ever seen, while in a ported box of a similar size, the same speaker had reasonable response.
Ooh err

Quote:
The driver has to push and pull a long column of air in two directions in a TH, that takes a real motor.
Points taken Thanks
  Reply With Quote
Old 30th October 2011, 05:47 PM   #10
bjorno is offline bjorno  Sweden
diyAudio Member
 
Join Date: Mar 2005
Location: Jacobsmountain
Send a message via MSN to bjorno
Quote:
Originally Posted by Zero D View Post
..I'm surprised others havn't been able to contribute with their data ? I thought there were quite a number of members on here who are more than just a little bit interested in TH designs etc !..
Zero D,

From post#1 I generated a bunch of fictive drivers for you to be ..DIY.. simulated in HR and evaluated for TH suitability .
Besides avoiding the lower row of drivers (Too low cone weights) Which one would be your driver choice?

b
Attached Images
File Type: gif TH_T-TQWP_T-TQWT-test-drivers.GIF (66.1 KB, 204 views)
  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
Collated Design Criteria/dimensions for Ariel ML-TL Design talsius Full Range 1 13th October 2011 05:28 AM
Criteria for well behaved clipping panson_hk Solid State 1 9th August 2010 02:35 PM
se, srpp, pcb design criteria Electroshocked Tubes / Valves 13 1st July 2009 08:20 PM
Reconstruction filter design criteria. Aiace Digital Line Level 2 18th April 2009 09:06 AM
Drivers selection criteria. beppe61 Multi-Way 8 19th April 2006 04:18 PM


New To Site? Need Help?

All times are GMT. The time now is 12:02 AM.


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