Scan-Speak Discovery woofers ragged FR below 100Hz? - 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 16th August 2011, 04:58 PM   #11
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
Quote:
Originally Posted by Saturnus View Post
Finally a manufacturer publish real and unsmoothed frequency response graphs, and then that's a bad thing?

I give supreme respect to Scan-Speak have the guts to do what no other speaker manufacturer dares.
SEAS have been doing this for years, as have vifa/speak/peerless. And if they have ever used smoothing it has only been a very small amount.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 16th August 2011, 08:02 PM   #12
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Silicon Valley, California
I agree that the Revelator woofers I heard made some of the best bass I've ever heard, although I had not examined an FR curve for them until now.

Here's shown the FR for a Scan-Speak Discovery 30W/4558T00 subwoofer, which looks very desirable in the bass (first pic):

The second pic is of a Seas Excel W22EX001 E0022, which appears smoothed.

And the third pic is of a Peerless XXLS 835017, which looks nice without any apparent smoothing.
Attached Images
File Type: png Scan-Speak 30W:4558T00 FR curve.png (66.7 KB, 268 views)
File Type: png Seas Excel W22EX001 E0022 FR curve.png (74.8 KB, 265 views)
File Type: png Peerless XXLS 12in 835017 FR curve.png (125.5 KB, 263 views)
  Reply With Quote
Old 16th August 2011, 08:13 PM   #13
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Silicon Valley, California
So the Scan-Speak Discovery woofer is ugly, but the SS Discovery subwoofer is nice? Same company, same series (Discovery aluminum cone), same test? Something's not right....
Attached Images
File Type: jpg ScanSpeak 26W:4534G00 FR.jpg (265.2 KB, 261 views)
File Type: png Scan-Speak 30W:4558T00 FR curve.png (66.7 KB, 227 views)
  Reply With Quote
Old 16th August 2011, 08:16 PM   #14
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by Andersonix View Post
So the Scan-Speak Discovery woofer is ugly, but the SS Discovery subwoofer is nice? Same company, same series (Discovery aluminum cone), same test? Something's not right....
Don't forget the DB scale, you've got one that jumps in 10db increments and the other is 5, it's going to look jumpier naturally.
  Reply With Quote
Old 16th August 2011, 08:24 PM   #15
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Silicon Valley, California
Quote:
Originally Posted by DrDyna View Post
Don't forget the DB scale, you've got one that jumps in 10db increments and the other is 5, it's going to look jumpier naturally.
You seriously don't see past that?
  Reply With Quote
Old 16th August 2011, 08:46 PM   #16
DrDyna is offline DrDyna  United States
diyAudio Member
 
DrDyna's Avatar
 
Join Date: May 2007
Blog Entries: 3
Quote:
Originally Posted by Andersonix View Post
You seriously don't see past that?
I think I do? I'm not sure precisely what you mean by that, but I was merely aiming to point out that even though one of those charts looks markedly worse than the other, it's only worse by 1 or 2 db.
  Reply With Quote
Old 16th August 2011, 09:13 PM   #17
diyAudio Member
 
Andersonix's Avatar
 
Join Date: Jan 2004
Location: Silicon Valley, California
One has almost 5dB of change within 10Hz in two places below 100Hz (and 4dB in three other places); the other one has barely 1dB wiggles anywhere below 100Hz....

It is those sharp 4-5dB up-down changes that makes me question whether a woofer can physically respond like that.

Last edited by Andersonix; 16th August 2011 at 09:16 PM.
  Reply With Quote
Old 16th August 2011, 09:30 PM   #18
diyAudio Member
 
Join Date: Sep 2006
Location: New England
Quote:
Originally Posted by Andersonix View Post
One has almost 5dB of change within 10Hz in two places below 100Hz (and 4dB in three other places); the other one has barely 1dB wiggles anywhere below 100Hz....

It is those sharp 4-5dB up-down changes that makes me question whether a woofer can physically respond like that.
I think the answer to your question must come from Scanspeak. Have you written to them and asked exactly how they test woofers and what level of smoothing they used in the published tests?
  Reply With Quote
Old 16th August 2011, 10:32 PM   #19
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
I really wouldn't worry about it. The SEAS graphs are obviously composites and any near-field measurement technique will give ruler flat/smooth responses in the bass.

Whenever you start introducing the room into the equation, peaks and dips like that can and will show up. Take a look at the 8 ohm version of that driver, the 8534. Even though the drivers are identical, except for the voice coil, the top end response of each is different. However the bass response is identical, one would assume that they had been measured at the same time too.

Now take a look at the revelator/classic/illuminator drivers under the 'woofer' section, they all show peak dip combos at roughly the same frequencies in the bass. It is obviously a measurement artefact.

Drivers typically display ruler flat frequency responses when they are operating within the cones pistonic range (at low frequencies). The only thing that would cause bumps/kinks would be a resonance of some sort and if severe enough they would also show up in the impedance plot.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  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
Zaph Audio ZA14W08 or Scan-Speak 15W/8434G00 Discovery mycity33 Multi-Way 0 30th December 2010 06:02 PM
FS: Scan-Speak Illuminator d3004/60200 Tweeters, Scan-Speak Discovery 10f Midrange bikinpunk Swap Meet 1 27th September 2010 04:13 PM
Your next extended range driver? Scan Speak Discovery 10F/4424G00 ScottG Full Range 54 18th August 2010 10:40 PM
Scan-Speak woofers nelsondog Swap Meet 3 28th August 2006 05:41 PM
New woofers Scan-Speak blank527 Multi-Way 1 16th November 2005 05:05 PM


New To Site? Need Help?

All times are GMT. The time now is 08:58 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