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The Accession's EQ's |
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Fatmangolf
Moderator Group Joined: 23 Dec 2009 Location: Middlesbrough Status: Offline Points: 8958 |
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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 |
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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. |
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tmoody
Regular Joined: 01 Apr 2018 Location: New York Status: Offline Points: 55 |
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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
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Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's |
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Chris Firth
Moderator Group Joined: 16 May 2013 Location: Rossendale, UK Status: Offline Points: 1529 |
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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
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tmoody
Regular Joined: 01 Apr 2018 Location: New York Status: Offline Points: 55 |
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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 :)
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Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's |
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Chris Firth
Moderator Group Joined: 16 May 2013 Location: Rossendale, UK Status: Offline Points: 1529 |
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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.
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Chris Firth
Moderator Group Joined: 16 May 2013 Location: Rossendale, UK Status: Offline Points: 1529 |
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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.
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tmoody
Regular Joined: 01 Apr 2018 Location: New York Status: Offline Points: 55 |
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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!
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Clearaudio Performance DC with Clarify Tonearm + Concerto V2 cart -> Accession MC -> Pass Labs INT-60 -> KEF Reference 3's |
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