Backloaded horns, do we want delayed bass, and how do we want it? - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 24th January 2014, 11:54 AM   #11
diyAudio Member
 
Phenoholic Anonymus's Avatar
 
Join Date: Dec 2013
I am not that interested in the true definition of horns. I am interested in how the backwave is handled. There is probably a better academic for backwave... A study showing a horn with a low Qes driver with a smooth path compared directly with a rough path would be welcome. A link where this is done in transmissionlines would be welcome to. I am interested in the crossover point from backwave to driver, in what i would call a backloaded horn.

Some questions about Hornresp
-how does hornresp handle mass rolloff Fs x 2/ Qes?
-would it be possible to move the hornmouth up or down in regard to the driver? Driver on the back of cabinet, distance to mouth x,y,z

Last edited by Phenoholic Anonymus; 24th January 2014 at 12:04 PM.
  Reply With Quote
Old 24th January 2014, 12:06 PM   #12
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Quote:
Originally Posted by Phenoholic Anonymus View Post
Thanks,

I have a fine >90 dB fullrange speaker at home. Would like to step it up to >100 dB, the Frugal horn looks are stunning.

If you can do it, well ...

But at what price ( in the remote case that the thing is achievable) ?
You'll still have two ( not counting the walls of the enclosure ) distinct sound sources, conflicting.
As I see you have Ajhorn ( I don't), I found very interesting the introduction.
  Reply With Quote
Old 24th January 2014, 01:24 PM   #13
diyAudio Member
 
Phenoholic Anonymus's Avatar
 
Join Date: Dec 2013
Thanks Pico,

I am familiar with single fullrange speakers. And what they can do in Back Loaded Horns. From a recent link in a HM art thread i found these numbers for the summation effect. Two sources need to be under 1.5 ms from each other to sum correctly. There is little information (links welcome!) about this effect in regards to Spl and frequency.

Click the image to open in full size.

It would be nice if we had a curve like this for hearing delay in regards with spl and Hz. The maximum length of a horn and where the high cut off (mass roll off, volume of chamber, etc) needs to be would imho follow from such a curve.

Last edited by Phenoholic Anonymus; 24th January 2014 at 01:26 PM.
  Reply With Quote
Old 24th January 2014, 01:39 PM   #14
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Different SPL- different velocity inside the "box". Sounds like there is only one optimal
level to be played for the typical horn enclosure, doesn't it ? Like T/S parameters that are found at very little levels...then compression arises as a magnet gets hotter.
So you'll still have to deal with driver's diameter when considering a fullrange driver: bigger bass but no highs or good dispersion with sacrificed SPL.
HAve you considered the low-pass properties of the bends ?
  Reply With Quote
Old 24th January 2014, 01:54 PM   #15
diyAudio Member
 
Phenoholic Anonymus's Avatar
 
Join Date: Dec 2013
Hi Pico,

The hornenclosure i am after is not for a fullrange driver. It's for a three way horn. 50-500 Hz, 500-3. kHz, 3 kHz ->. I just found this driver: Oberton 8M250 I hope to end up with this driver for the 1/3 backloaded horn experiment. I am interested in moving up a little bit in frequency with this driver 50-600 or 700Hz, hope to get there by shortening the path of the woofer to the hornmouth by offset placement in the horn / cabinet. So for this purpose i need to know more about usable frequency from the backwave of the horn. (and the effect of bends

Last edited by Phenoholic Anonymus; 24th January 2014 at 01:58 PM.
  Reply With Quote
Old 24th January 2014, 02:17 PM   #16
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Quote:
8M250 is intended for use as a direct radiating or horn loaded midrange speaker.
I would trust the manufacturer.
Wrong choice, try again !

And...you didn't specify for which usage you intend to put these drivers into..exercise. For in-home use a 50/100 W driver is ok.
So for home the making of the project includes the positioning, where you are placed, too, or wheter you move around...So the integration of direct radiation and what follows in propagation of the back wave is also dependent of near-fiel or far field listening position. I wouldn't trust too much that 1,5 ms time for distinguishing between the sources ( the mouth ...) which is real low but what happens if/when you put your attention to what really happens ?
Any "timing" would then result "good" if the speaker " sounds good" .
  Reply With Quote
Old 24th January 2014, 02:41 PM   #17
diyAudio Member
 
Phenoholic Anonymus's Avatar
 
Join Date: Dec 2013
I am not that worried about the intended use of the 8M250 Oberton. Xmax is low with 1.0 mm that's for sure. But for example Xmax for the Fostex FE208 Sigma used in the Jericho horn is 0.75 mm. And that seems to work alright.

Intended use is at home with 8 to 10 watt tube amp. Listening distance 3.0 meters and up. +-35m2 room.
  Reply With Quote
Old 24th January 2014, 03:14 PM   #18
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
Oh yes, a fat coil to overcome the rising response and it 'll settle at 90-91 dB.

BTW I built something similar to the Jericho horn in 1997 ( a little late ! That project is from '96 ) with lateral mouth. Some drivers passed around ( replacing the dead ones )the first being Pioneer then Goldsound ( Similar to Pioneer's BOFU !?! ) which were 7" now it houses a Vifa 8". Now they're two ways with a 2" mid-tw in a BIG 8" waveguide ( made from a a dead speaker, guess...). Sort of mix between the jericho design and an expanding TL by putting some resistance at the terminus /mouth.
But real bass is another thing, or it isn't ?
"Seems" it's not a valid term
  Reply With Quote
Old 24th January 2014, 03:23 PM   #19
diyAudio Member
 
Phenoholic Anonymus's Avatar
 
Join Date: Dec 2013
Speaking of Jericho, this is an extremly interesting thread in the German spoken Visaton forum, about horns: Welche Daten muss ein Horntreiber haben? - Visaton Diskussionsforum

Click the image to open in full size.

Nearfield measurement of the mouth of the Jericho horn.

Click the image to open in full size.

Seems the bandpass limiting effect of the small backchamber is not that great. -6dB at 1 kHz there is still an awful amount of noise coming out of the mouth. Pico, i just did a google search for lateral mouth (....) feel free to post a picture to show what you mean. Breaks down the language barrier!

Last edited by Phenoholic Anonymus; 24th January 2014 at 03:37 PM.
  Reply With Quote
Old 24th January 2014, 03:32 PM   #20
diyAudio Member
 
picowallspeaker's Avatar
 
Join Date: Apr 2007
I like what member Patrick says at page 5
Even if I don't understand a word
...but he says it right !
  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
Smaller Fostex Backloaded Horns Persona Full Range 29 27th November 2012 11:03 AM
Best Firstwatt amp for backloaded horns? blue lander Pass Labs 55 24th May 2012 01:25 AM
WTB: Fostex backloaded horns, complete or just cabs jim_vt Swap Meet 0 13th July 2005 01:49 PM
Fostex Backloaded horns dreaded 42 Multi-Way 5 25th March 2004 03:27 PM
Bass Horns? Chris_SWE Multi-Way 7 7th January 2002 03:58 AM


New To Site? Need Help?

All times are GMT. The time now is 09:30 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