Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

New Peerless STW350 subwoofer on the horizon...
New Peerless STW350 subwoofer on the horizon...
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 11th July 2017, 05:48 PM   #11
wolf_teeth is offline wolf_teeth  United States
diyAudio Member
 
wolf_teeth's Avatar
 
Join Date: Mar 2006
Location: Indiana
Now that I've seen another magnet geometry pic, I agree that it's a single gap. I went back and looked at my saved photo from a year ago. What isn't clear in that photo is the gap area without a physical picture. What is apparent is that there are 2 magnet structures flanking the long gap, and that is what threw me off. Before it looked like two gaps and a spacer ring, with a single coil. I never said it had 2 coils other than being a DVC architecture. The long coil was longer than what I saw as 'both gaps' before.

Again- agreed that it's just a really long gap and longer coil, and 2 tiered magnet structures flanking the gap.

Later,
Wolf
Attached Images
File Type: jpg STW350cutaway.jpg (26.9 KB, 241 views)
__________________
Photobucket picture pages: http://photobucket.com/Wolf-Speakers_and_more
Writeups/thoughts/blogs: http://techtalk.parts-express.com/blog.php?u=4102
  Reply With Quote
Old 12th July 2017, 06:35 AM   #12
bcodemz is offline bcodemz  Canada
diyAudio Member
 
Join Date: Feb 2014
The SVS PB16 Ultra uses this driver, or a variant of this. Audioholics has tested this subwoofer outdoors with a ground plane measurement. The maximum distortion limited output capabilities are excellent. In 20Hz tuned mode, 122.9dB at 25Hz with 2.7% THD and 119.8dB at 20Hz with 11.8% THD from 1 meter.

http://www.audioholics.com/subwoofer...r/measurements
  Reply With Quote
Old 12th July 2017, 07:09 AM   #13
GM is offline GM  United States
diyAudio Member
 
GM's Avatar
 
Join Date: Jun 2003
Location: Chamblee, Ga.
I'm surprised nobody has paid to use Babb's spiderless, ball bearing design to get very high linear Xmax. They were making ~4.5" [IIRC] 'FR' drivers with either 1" or 1.2" Xmax/400 W peak ages ago. Scale that up to a large subwoofer........ The only downside [at least then] was the surround couldn't handle any sort of compression loading, so no BPs or horns.

GM
__________________
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
  Reply With Quote
Old 12th July 2017, 08:32 AM   #14
gbullimore is offline gbullimore  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
it's an interesting design, but in reality just moves the design burden to the surround,
you still need a given level of restoring force and progressive limit to compliance,
sharing this between spider and surround helps design wise,
  Reply With Quote
Old 12th July 2017, 03:10 PM   #15
Josh Ricci is offline Josh Ricci  United States
diyAudio Member
 
Join Date: Apr 2009
Quote:
Originally Posted by bcodemz View Post
The SVS PB16 Ultra uses this driver, or a variant of this. ]
Correct. SVS marketing says it's an 8" coil but the Peerless literature says it is actually 7.4" diameter.

The smaller top magnet in the motor is used to force more flux through the gap and top plate.

There are some things I like about this driver and some that I don't. For all of that huge coil and heavy ferrite / steel motor it manages a very lackluster qts. It is very inefficient. Great at low sub bass but mediocre at best in the 40-100Hz range where most of the music is. The design lends itself to a NdFeb magnet system but they used ferrite. It almost seems like they designed it for neo and then realized the cost and decided to make ferrite work.
  Reply With Quote
Old 17th July 2017, 04:21 PM   #16
gbullimore is offline gbullimore  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
the challenge is actually how to keep the Qts high,
it's easy to find a driver with 0.2 Qt, but as a subwoofer this performs badly in cabinet and requires a lot of electrical compensation . unless of course you use an overly small cabinet and push up the Fs a lot,
the driver was specifically designed to be ferrite from the start,
the combination of Qt suitable for either vented or sealed cabinet, and low Fs whilst maintaining a very low Vas is not easy to achieve,
compare the driver against others in such a small box and see what the performance looks like!
  Reply With Quote
Old 17th July 2017, 05:03 PM   #17
Josh Ricci is offline Josh Ricci  United States
diyAudio Member
 
Join Date: Apr 2009
Quote:
Originally Posted by gbullimore View Post
the challenge is actually how to keep the Qts high,
it's easy to find a driver with 0.2 Qt, but as a subwoofer this performs badly in cabinet and requires a lot of electrical compensation . unless of course you use an overly small cabinet and push up the Fs a lot,
the driver was specifically designed to be ferrite from the start,
the combination of Qt suitable for either vented or sealed cabinet, and low Fs whilst maintaining a very low Vas is not easy to achieve,
compare the driver against others in such a small box and see what the performance looks like!
I will have to respectfully disagree.
Keeping Qts high or raising it is easy. Think of it like MPG/KPG in a car. It's not too hard to make an 10 mpg vehicle. Extremely difficult to make a practical 300 mpg car.
Drivers with middle to high Qts and low Vas have been common in car audio for a long time.
  Reply With Quote
Old 17th July 2017, 05:19 PM   #18
gbullimore is offline gbullimore  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
I Josh, you are welcome to disagree,

there are other drivers out there that also have high Qt and low Vas, but many of them are not great for home use, they are either too noisy (air noise) very insensitive, or have other issues,

the STW was primarily designed for home audio, and for low distortion, high excursion use in small boxes, there is not much around to compete with it like for like.

and yes, it takes some work to get a low Vas and low Fs, whilst keeping reasonable sensitivity and low distortion, with a manageable Qt,
this driver could easily have been made with a Qt of 0.2 but it would be worse for it!


it's also important not just to rate a driver based on a few numbers on the spec sheet, but to also consider the non-numerical things,
  Reply With Quote
Old 17th July 2017, 06:27 PM   #19
badman is offline badman  United States
diyAudio Member
 
badman's Avatar
 
Join Date: Sep 2003
Location: Sunny Tustin, SoCal
Quote:
Originally Posted by Josh Ricci View Post
I will have to respectfully disagree.
Keeping Qts high or raising it is easy. Think of it like MPG/KPG in a car. It's not too hard to make an 10 mpg vehicle. Extremely difficult to make a practical 300 mpg car.
Drivers with middle to high Qts and low Vas have been common in car audio for a long time.
Agreed. Just weaken the motor, done.
__________________
"The dawn of Bose created the "Man Cave" and reduced testoterone levels worldwide by 18.5 per cent" Peteleoni
  Reply With Quote
Old 18th July 2017, 12:47 AM   #20
gbullimore is offline gbullimore  United Kingdom
diyAudio Member
 
Join Date: Jun 2007
If you just weaken the motor you have low BL and very low sensitivity.
For a 15" driver with such a low FS and VAS you need a very high Mms which means a strong motor is needed to give reasonable sensitivity.
  Reply With Quote

Reply


New Peerless STW350 subwoofer on the horizon...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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Subwoofer Peerless emisgallo Subwoofers 10 18th June 2013 10:14 PM
Small subwoofer using Peerless 830946 Sumba Subwoofers 15 10th May 2010 06:56 AM
Just ordered my new subwoofer (Peerless) harrisni Subwoofers 57 11th June 2007 12:16 AM
My insane Peerless subwoofer Mikael Abdellah Subwoofers 26 21st February 2006 09:26 AM
Peerless Subwoofer Andy_Mac Subwoofers 26 2nd September 2002 11:18 AM


New To Site? Need Help?

All times are GMT. The time now is 03:27 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki