New Posts New Posts RSS Feed - The Accession's EQ's
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Welcome to the Graham Slee Audio Products Owners Forum

 

Open to all owners plus those contemplating the purchase of a Graham Slee HiFi System Components audio product and wishing to use this forum's loaner program: join here (Rules on posting can be found here)

This website along with trade marks Graham Slee and HiFi System Components are owned by Cadman Enterprises Ltd


The Accession's EQ's

 Post Reply Post Reply Page  <12345>
Author
Fatmangolf View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 23 Dec 2009
Location: Middlesbrough
Status: Offline
Points: 8958
Post Options Post Options   Thanks (1) Thanks(1)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:12pm
There isn't a subsonic filter on any of the GSP gear. I'm giving my quick answer before a proper explanation from Graham and others by saying I think the impact on the audio range of the high pass filter is worse* than the visible but inaudible woofer pumping you describe. It does happen and is visible on reflex cabs because the speaker driver is not damped at low frequences by the cabinet and its port.

*Clearly extreme woofer pumping could at high volumes exceed the maximum excursion of the cones. That would be worse.

As I understand it, other may contribute further, it is because most records aren't completely flat and this can be emphasised by feedback through the cabinet and floor (mine was and made the springs bounce, pumping the speaker cones. I lived with this until I changed the hifi cabinet), the resonance of the cartridge and arm being outside the recommended range. You can isolate the turntable with gel pads and other absorbant materials, check and retune the arm/cart resonance if needed. Moving any speakers close to your turntable will help, especially if they are on the same floorboard or beam.

***I like Chris' answer - very good advice***


Edited by Fatmangolf - 02 Jun 2018 at 8:14pm
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
Back to Top
tmoody View Drop Down
Regular
Regular


Joined: 01 Apr 2018
Location: New York
Status: Offline
Points: 55
Post Options Post Options   Thanks (0) Thanks(0)   Quote tmoody Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:34pm
Originally posted by Fatmangolf Fatmangolf wrote:

There isn't a subsonic filter on any of the GSP gear. I'm giving my quick answer before a proper explanation from Graham and others by saying I think the impact on the audio range of the high pass filter is worse* than the visible but inaudible woofer pumping you describe. It does happen and is visible on reflex cabs because the speaker driver is not damped at low frequences by the cabinet and its port.

*Clearly extreme woofer pumping could at high volumes exceed the maximum excursion of the cones. That would be worse.

As I understand it, other may contribute further, it is because most records aren't completely flat and this can be emphasised by feedback through the cabinet and floor (mine was and made the springs bounce, pumping the speaker cones. I lived with this until I changed the hifi cabinet), the resonance of the cartridge and arm being outside the recommended range. You can isolate the turntable with gel pads and other absorbant materials, check and retune the arm/cart resonance if needed. Moving any speakers close to your turntable will help, especially if they are on the same floorboard or beam.

***I like Chris' answer - very good advice***

The woofer pumping isn't entirely inaudible during one spot in particular (the last part of Bohemian Rhapsody, during which things quiet down to only the piano and vocals). However, there's a good deal or warble in that spot, so it may just be that the vinyl is in bad shape even if it doesn't look that way.

Not surprised to hear that the negatives of a high pass may outweigh the benefits. The Harrison Labs stuff is passive, and inexpensive (and can be returned) so I may just order the 20 and 30Hz to see. And the socks LOLLOL
____________________________________________________________________________
Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's
Back to Top
Chris Firth View Drop Down
Moderator Group
Moderator Group


Joined: 16 May 2013
Location: Rossendale, UK
Status: Offline
Points: 1529
Post Options Post Options   Thanks (0) Thanks(0)   Quote Chris Firth Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:36pm
KEF have taken their eye off the ball before - they had a deadened to almost being anechoic listening room built once.
What's the betting the REF 3 was designed with digital source material?
It never occurred that someone might play vinyl sources?

Looking at the REF 3, it appears that the port tuning can be adjusted - try lengthening the port and take the tuning upwards Wink
Back to Top
tmoody View Drop Down
Regular
Regular


Joined: 01 Apr 2018
Location: New York
Status: Offline
Points: 55
Post Options Post Options   Thanks (0) Thanks(0)   Quote tmoody Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:49pm
Originally posted by Chris Firth Chris Firth wrote:

KEF have taken their eye off the ball before - they had a deadened to almost being anechoic listening room built once.
What's the betting the REF 3 was designed with digital source material?
It never occurred that someone might play vinyl sources?

Looking at the REF 3, it appears that the port tuning can be adjusted - try lengthening the port and take the tuning upwards Wink

Yes they come with two port insert, a short and a long. I have the longs in currently so only option besides socks are to switch to the shorter ones (which, of course, are in the boxes, in a storage room I have to visit...ARGH!)

Or, are you saying to literally pull the port insert out so that it sticks out the back? That's not a position explicitly endorsed in the speaker manual, but I'm willing to give it a go :)
____________________________________________________________________________
Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's
Back to Top
Chris Firth View Drop Down
Moderator Group
Moderator Group


Joined: 16 May 2013
Location: Rossendale, UK
Status: Offline
Points: 1529
Post Options Post Options   Thanks (1) Thanks(1)   Quote Chris Firth Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:58pm
I meant to make the port longer - it appears on the images that the ports can be lengthened or shortened by a screwlike mechanism on the port surround.
If that's not the case then socks it is.
Or a cut up bath sponge, or possibly a bundle of drinking straws filling the port tube.
Back to Top
Chris Firth View Drop Down
Moderator Group
Moderator Group


Joined: 16 May 2013
Location: Rossendale, UK
Status: Offline
Points: 1529
Post Options Post Options   Thanks (1) Thanks(1)   Quote Chris Firth Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 8:59pm
The problem is that the port is tuned to somewhere near or at the natural resonant frequency of the driver - you need to break that up somehow.
Back to Top
tmoody View Drop Down
Regular
Regular


Joined: 01 Apr 2018
Location: New York
Status: Offline
Points: 55
Post Options Post Options   Thanks (0) Thanks(0)   Quote tmoody Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jun 2018 at 9:11pm
Originally posted by Chris Firth Chris Firth wrote:

The problem is that the port is tuned to somewhere near or at the natural resonant frequency of the driver - you need to break that up somehow.

Gotcha. Makes sense. I will play around...may also ask KEF about the port. Seems that the long and short versions both go all the way in so that they are ultimately flush with the rear. But maybe pulling it out is okay...

Thanks!
____________________________________________________________________________
Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's
Back to Top
 Post Reply Post Reply Page  <12345>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 0.090 seconds.