Compression driver selection & Revision log - Page 3 - diyAudio
Go Back   Home > Forums > Live Sound > PA Systems

PA Systems A forum for discussion of all parts of a sound reinforcement or DJ system: loudspeakers, mixers (desks) etc.

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 January 2014, 11:56 PM   #21
diyAudio Member
 
Join Date: Mar 2013
Quote:
Originally Posted by Joseph Crowe View Post
The QSC speakers that are currently in use are HPR-122i.

QSC HPR122i 12" 2-Way Powered Multipurpose Loudspeaker | Musician's Friend
Oh they're nice.. are you trying to better them with this build?

  Reply With Quote
Old 26th January 2014, 03:35 AM   #22
diyAudio Member
 
Join Date: Mar 2012
Location: Belleville Ontario, Canada
Quote:
Originally Posted by conanski View Post
Oh they're nice.. are you trying to better them with this build?
The QSC's have quite a few issues that I don't really feel like going into right now but I'm already way past bettering them. They've served their purpose for the past three years and it's time to upgrade.
  Reply With Quote
Old 26th January 2014, 05:16 PM   #23
diyAudio Member
 
Join Date: Mar 2013
Quote:
Originally Posted by Joseph Crowe View Post
The QSC's have quite a few issues that I don't really feel like going into right now but I'm already way past bettering them..
Sorry I wasn't trying to suggest the QSCs were the end all be all of powered speakers, they're a decent little box but they have been bettered by subsequent releases by QSC and others and I'm sure they can be bettered with a DIY design.
  Reply With Quote
Old 14th February 2014, 04:51 AM   #24
Speakerholic
diyAudio Member
 
Join Date: Aug 2011
Location: Near Eminence KY
I am still working on acquiring those B&C compression drivers. In the mean time the Daytons work, and I want to throw in a little story here.

I do live sound reinforcement with the same band every Thursday night, but it isn't in a permanent location so we always have to load in and load out our own equipment. And sometimes the band likes to change around their instruments. Today I was told we would be doing an acoustic night, just the lead singer, two acoustic guitars, and a minimal acoustic drum set lacking a kick drum. Naturally, this means I would have no need to bring my huge sub, thus saving effort. Oh yeah, and the group right before us was scheduled to cut into our setup time, leaving us an hour where we normally have two or three.

It's a trap.

My drummer shows up with his electric drums. No time to change setup, we'll be sending the kick drum through the Beta-12LTA drivers without a HPF. These are 12" drivers keep in mind, in a sealed enclosure.

I was surprisingly very impressed with the performance of the LTAs. Defiantly, the bass was lacking impact. But it wasn't as if the kick drum was absent by any means. The over all level actually blended really well with the two acoustic guitars.

Beta-12LTA is a real workhorse. I will post frequency response measurements as soon as I get them; as soon as I find big, empty space.
__________________
In one thousand years, will they still be called the Thiele Small parameters?

Last edited by Thetwinmeister; 14th February 2014 at 04:53 AM.
  Reply With Quote
Old 14th February 2014, 08:09 PM   #25
diyAudio Member
 
Join Date: Mar 2012
Location: Belleville Ontario, Canada
Quote:
Originally Posted by Thetwinmeister View Post
I am still working on acquiring those B&C compression drivers. In the mean time the Daytons work, and I want to throw in a little story here.

I do live sound reinforcement with the same band every Thursday night, but it isn't in a permanent location so we always have to load in and load out our own equipment. And sometimes the band likes to change around their instruments. Today I was told we would be doing an acoustic night, just the lead singer, two acoustic guitars, and a minimal acoustic drum set lacking a kick drum. Naturally, this means I would have no need to bring my huge sub, thus saving effort. Oh yeah, and the group right before us was scheduled to cut into our setup time, leaving us an hour where we normally have two or three.

It's a trap.

My drummer shows up with his electric drums. No time to change setup, we'll be sending the kick drum through the Beta-12LTA drivers without a HPF. These are 12" drivers keep in mind, in a sealed enclosure.

I was surprisingly very impressed with the performance of the LTAs. Defiantly, the bass was lacking impact. But it wasn't as if the kick drum was absent by any means. The over all level actually blended really well with the two acoustic guitars.

Beta-12LTA is a real workhorse. I will post frequency response measurements as soon as I get them; as soon as I find big, empty space.
Yes I've had many nightmares about being thrown into situations that were out of my control regarding live sound. One thing I have learned is that if anything can go wrong it will go wrong.
If you ever want to build a stellar sub I recommend an onken style enclosure being driven by the latest class D amps.
  Reply With Quote
Old 14th February 2014, 10:27 PM   #26
Speakerholic
diyAudio Member
 
Join Date: Aug 2011
Location: Near Eminence KY
I was not previously aware of the Onken style design. To my new understanding, it's basically a large reflex alignment box? At this point I'm trying to get smaller, however. heh

Have you had any experience with the Cubo 15/18 or Cubo Sub or similar types of designs? They seem appealing because of retaliative small size and good extension/sensitivity.
__________________
In one thousand years, will they still be called the Thiele Small parameters?
  Reply With Quote
Old 14th February 2014, 10:57 PM   #27
Speakerholic
diyAudio Member
 
Join Date: Aug 2011
Location: Near Eminence KY
Found this! Dual 15" Subwoofer project complete

Good Job--looks great.
__________________
In one thousand years, will they still be called the Thiele Small parameters?
  Reply With Quote
Old 15th February 2014, 02:59 AM   #28
diyAudio Member
 
Join Date: Mar 2012
Location: Belleville Ontario, Canada
I've seen the cubo designs but I've never heard them before. Two things stand out about the cubo that concerns me, first is the lack of any imperial data regarding frequency response and efficiency. Secondly the horn length is very short and therefore would not provide any low frequency extension which is probably why I haven't been able to find any data on it. The onken style enclosure is a very large box, but it's been my experience that to get good pitch definition you need a large box. I've seen people dismiss the onken design but after a lot of thought I think it's doing something a little more than a basic bass reflex function. It seems as though the symmetrical slot openings are coupling all the air inside the cabinet. In a traditional ported enclosure there are air pockets that act separate from the main event causing rippled in the impedance and FR curves. The result is less pitch definition since there are spurious acoustical events inside the cabinet.
  Reply With Quote
Old 15th February 2014, 03:31 AM   #29
Speakerholic
diyAudio Member
 
Join Date: Aug 2011
Location: Near Eminence KY
Quote:
Originally Posted by Joseph Crowe View Post
I've seen the cubo designs but I've never heard them before. Two things stand out about the cubo that concerns me, first is the lack of any imperial data regarding frequency response and efficiency. Secondly the horn length is very short and therefore would not provide any low frequency extension which is probably why I haven't been able to find any data on it. The onken style enclosure is a very large box, but it's been my experience that to get good pitch definition you need a large box. I've seen people dismiss the onken design but after a lot of thought I think it's doing something a little more than a basic bass reflex function. It seems as though the symmetrical slot openings are coupling all the air inside the cabinet. In a traditional ported enclosure there are air pockets that act separate from the main event causing rippled in the impedance and FR curves. The result is less pitch definition since there are spurious acoustical events inside the cabinet.
You have me interested now. For various reasons including the one you stated, I have tried to avoid ported enclosures. Another big reason is as power increases port tuning increases in frequency-- not good!

The sub I built is sealed, but it's sealed isobaric push-pull. I am a huge proponent of isobaric push-pull. I don't have all the empirical data assembled to claim it can't be beaten by a single driver in cost or/nor performance, but I like what I've read and heard empirically.

As a home theater sub, what I built is fantastic. Plenty of extension with more clarity than you could dream of at the price point for the drivers I selected. It doesn't do fantastically on stage though. Just well. It's a good sub, but it isn't amazing like I want it to be.

As you may or may not know, isobaric configuration reduces the Vas to half of the single driver, thus reducing box size requirement by half. Unfortunately, it isn't all magic as you are still required much physical space to link two drivers where there would otherwise be just one.

None the less, I would like to get your opinion on the theoretical possibility of combining onken with isobaric push-pull. Based on your experience, is reducing the Vas of the drivers by half a good thing in the onken alignment? Would reducing the Vas translate to reducing box size in onken? If the answers to these questions are yes, then I will seriously contemplate building an onken box.

I will probably build a Cubo-something along the way anyway, if nothing else to take measurements. If it does actually work I rather like the concept.
__________________
In one thousand years, will they still be called the Thiele Small parameters?
  Reply With Quote
Old 15th February 2014, 04:09 AM   #30
diyAudio Member
 
Join Date: Mar 2012
Location: Belleville Ontario, Canada
Quote:
Originally Posted by Thetwinmeister View Post
You have me interested now. For various reasons including the one you stated, I have tried to avoid ported enclosures. Another big reason is as power increases port tuning increases in frequency-- not good!

The sub I built is sealed, but it's sealed isobaric push-pull. I am a huge proponent of isobaric push-pull. I don't have all the empirical data assembled to claim it can't be beaten by a single driver in cost or/nor performance, but I like what I've read and heard empirically.

As a home theater sub, what I built is fantastic. Plenty of extension with more clarity than you could dream of at the price point for the drivers I selected. It doesn't do fantastically on stage though. Just well. It's a good sub, but it isn't amazing like I want it to be.

As you may or may not know, isobaric configuration reduces the Vas to half of the single driver, thus reducing box size requirement by half. Unfortunately, it isn't all magic as you are still required much physical space to link two drivers where there would otherwise be just one.

None the less, I would like to get your opinion on the theoretical possibility of combining onken with isobaric push-pull. Based on your experience, is reducing the Vas of the drivers by half a good thing in the onken alignment? Would reducing the Vas translate to reducing box size in onken? If the answers to these questions are yes, then I will seriously contemplate building an onken box.

I will probably build a Cubo-something along the way anyway, if nothing else to take measurements. If it does actually work I rather like the concept.
Yes isobaric will also work with the onken enclosure thus reducing the required internal volume to half. The other benefit is that the effective Fs of the drivers is cut in half so for example if your pro audio drivers have an Fs of 40hz, you would now have an Fs of 20hz! There is no free lunch though. With a traditional dual onken each drivers efficiency is combined so 92db x2 = 95 Db. But with an isobaric configuration your looking at 92 Db /2 = 89 Db. Which is why you don't see it used in pro applications. However for home theater it's perfect. Save space, get deep bass, and class d power is cheap. Isobaric does have another advantage too which is lower distortion, especially if the drivers can oppose each other, thus cancelling out the physical non linearities in the cone's travel. Also any non linearities caused by poor motor design will be overcome, so bad drivers tend to sound their best aka cheap inexpensive drivers on clearance from parts-express.
  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
cheap B&C NEO compression driver seanny Multi-Way 1 28th May 2012 08:30 AM
B&C Compression Driver and Horns warnsey Multi-Way 270 9th November 2008 10:33 PM


New To Site? Need Help?

All times are GMT. The time now is 06:21 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