Collaborative Tapped horn project - Page 90 - 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 31st December 2007, 02:32 PM   #891
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally posted by AndrewT

No!!! don't go opening up an access panel like the Labhorn has.
Greets!

I don't have the aversion to an access panel that you apparently do, but if you consider a rising response an acceptable trade-off (I do since it's better damped, but this thread seems to be 'max flat' centric) you can shift the driver position to the extreme end for easy access through the mouth, making the layout:

L12 = ~92.39 cm
L23 = ~342.42 cm
L34 = ~15.24 cm

GM
Attached Images
File Type: gif kef b139b 20-80 hz tapped pipe - alternate.gif (21.6 KB, 856 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 31st December 2007, 02:47 PM   #892
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally posted by pinkmouse

.......but they would work in that configuration.

........THs are very sensitive to driver parameters.
Although at a nominal -12 dB, or ~95 dB peak/TH/Xmax for this TH.

Right, just as regular band-pass alignments do, only more so.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 31st December 2007, 03:29 PM   #893
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally posted by rcavictim

I have a pair of 12 inch Hollywood 1280-D 400W RMS car type subwoofer drivers (2X 4 ohm VC`s each) that have plenty of excursion and large magnets that I think could be OK for a HT sub.
I wonder how close their specs are to these?:

GM
Attached Images
File Type: gif hollywood x2-1280d specs.gif (46.7 KB, 880 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 31st December 2007, 06:43 PM   #894
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
I have no problem with a slight rising response, but it's too late now!

Well, I had to stop for the night as there are very young children next door who are easily disturbed, so no more progress tonight. All I have left to do is put in the mounting plate for the access panel and wire it up, so I might get it fired up tomorrow before I have to go out.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 31st December 2007, 09:55 PM   #895
diyAudio Member
 
rcavictim's Avatar
 
Join Date: Jun 2004
Location: Next to an open wormhole NW of Toronto
Quote:
Originally posted by GM


I wonder how close their specs are to these?:

GM

GM,

That looks exactly like my drivers except mine have a slightly different style removable rubber cover on the stacked magnet assembly. Xmax one way spec sounds about right. I can confirm Fs as that is a simple test but do not know how to measure TS parameters yet myself.

What is your opinion of trying to make a stacked horn sub for a single or pair of these? Only want one cabinet if possible, coffee table style folded box would fit in well here. 10-15 Hz to 50 Hz should be good fill below my FR stereo mains that actually do go to 20 and I can hear at 30-35 Hz but don`t shake the room at the flea tube power I run.

I worry the published Fs (24.3 Hz) may be too low to use in a TH. Is this model driver used as a pair better suited for a labhorn type enclosure?
__________________
On April 01,2012, my radioastronomy Project TARGET SETI search succeeded. The signal came via extradimensional subspace, not radio waves. I now get a lot of 'visitors'. I took my avatar pic of one friend watching me in my work yard from just 20 ft. away.
  Reply With Quote
Old 31st December 2007, 11:26 PM   #896
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Ah well, when I posted some rising response sims of other drivers earlier in the thread they were ignored, but folks comment on and strive for the ~flat ones, so didn't bother to suggest it.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 31st December 2007, 11:55 PM   #897
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Quote:
Originally posted by rcavictim

What is your opinion of trying to make a stacked horn sub for a single or pair of these? Only want one cabinet if possible, coffee table style folded box would fit in well here. 10-15 Hz to 50 Hz.........
Greets!

At a glance, with a fairly high Vas, high Qts combined with a max gain BW of only ~10.75 - 54.92 Hz we're looking at a large 'one note' boombox if either a tapped pipe or conic horn and when I shift 'Fl' up to 14 Hz I wind up with ~122 dB from ~18-50 Hz if a 14 Hz expo flare is used, but it's a whopping ~345.3 ft^3! Using two drivers in clamshell isobaric will cut this to ~86.32 ft^3 and have a similar output due to doubling the Xmax, but still an unacceptably large cab, so until I can look at TLs, I've got nothing for you.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 1st January 2008, 03:34 AM   #898
diyAudio Member
 
rcavictim's Avatar
 
Join Date: Jun 2004
Location: Next to an open wormhole NW of Toronto
Quote:
Originally posted by GM


Greets!

At a glance, with a fairly high Vas, high Qts combined with a max gain BW of only ~10.75 - 54.92 Hz we're looking at a large 'one note' boombox if either a tapped pipe or conic horn and when I shift 'Fl' up to 14 Hz I wind up with ~122 dB from ~18-50 Hz if a 14 Hz expo flare is used, but it's a whopping ~345.3 ft^3! Using two drivers in clamshell isobaric will cut this to ~86.32 ft^3 and have a similar output due to doubling the Xmax, but still an unacceptably large cab, so until I can look at TLs, I've got nothing for you.

GM
GM,

Hmmm, one note boombox, pretty much the definition of a car subwoofer system no doubt, the application for which these drivers were clearly made.

Thanx for taking the effort to examine their suitability in a tapped horn (sorry I had a flash of mentalpause when I typed `stacked horn`), and also in a expo/conical horn. You are right about the cabinet being unacceptably large.

Shortly after fixing these and drying them out I duct taped one into the end of a 12 inch sonotube and had a second nesting section that could be used as a trombone element. This assembly was lain on the living room carpet and testing pursued with audio sine wave gen and low power (40 watts/ch RMS) SS amp. Each voice coil got a 40 watt channel to drive it. What I got was definitely not a `one note bass` wonder but it seemed the open ports were totally in the wrong places to properly excite the room. I did get a lot of the usual shaking and rattling however. I tried open ended and closed ended line with different tuning lengths up to about 17 feet IIRC.

There may be something there for these drivers in a traditional folded TL or pipe cabinet, with or without taper. I suspect they should be used mounted with the cone facing horizontally. Left sitting on their backs the cone has sunk a lot into the magnet structure,
__________________
On April 01,2012, my radioastronomy Project TARGET SETI search succeeded. The signal came via extradimensional subspace, not radio waves. I now get a lot of 'visitors'. I took my avatar pic of one friend watching me in my work yard from just 20 ft. away.
  Reply With Quote
Old 1st January 2008, 04:08 AM   #899
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
Happy New Year and all that jive!

Well, when all else fails, a TL will usually get the job done, though to keep the size semi-reasonable with this driver means it has to be Isobaric. Assuming a 200" long square tube just big enough to mount a driver (~12.5" square) = ~13.92 ft^3 or < 4 ft^2 before factoring in all the divider thicknesses and the extension to house the clamshelled driver. 1 W shown and with Isobaric you have 2x the excursion, so should pound pretty good and once the ripple is XO'd down will have a very good transient response:

GM
Attached Images
File Type: gif hollywood x2-1280d 17 hz tl - isobaric.gif (8.8 KB, 760 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 1st January 2008, 04:26 AM   #900
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
OK, the end loaded TL folded back on itself to make it a tapped pipe. It doesn't have as flat a gain BW as the TL:

GM
Attached Images
File Type: gif hollywood x2-1280d 17 hz tl - isobaric (hornresp).gif (19.4 KB, 749 views)
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  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



New To Site? Need Help?

All times are GMT. The time now is 11:49 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