Blue Shadow
Waiting for Vintage Gear from this century
Nakamichi did. The SF-10 designed for tts. Looks like it doesn't roll off fast enough and starts a bit early but it works. Maybe have Gadget over to give em a listen.
Unsolvable Woofer Pumping (Phono only)
- Thread starter branden_8091
- Start date
JMelton
Active Member
You are saying the turntables didn't cause this (or every turntable has the same problem) and the preamp didn't cause this (or every preamp. has the same problem).
So are you implying the cables between the turntable and preamp are the problem? There isn't anything else left.
Since it went away with the subsonic filter engaged in a preamp it's likely a feedback problem with the turntables. If not accoustic then electrical, but an accoustic problem is more common.
If it's not anything then you are imagining the whole thing... it's probably not imaginary so it's likely one of the things you said it "can't be".
You are saying the turntables didn't cause this (or every turntable has the same problem) and the preamp didn't cause this (or every preamp. has the same problem).
So are you implying the cables between the turntable and preamp are the problem? There isn't anything else left.
He needs to rule-out placement of the turntable, with respects to the rest of his system.
JMelton
Active Member
I was wondering if just moving the speakers around the room makes a difference.
But honestly it seems like a subsonic filter fixes the problem so the solution is to use a subsonic filter. Problem solved.
Vinylmasters
Super Member
First I have ever heard of these! I tried the Harrison Labs one and it snuffs all life out of the music.
Hobie1dog
subaholic
exact same issue with a friends stereo, but he refuses to acknowledge that there is a problem with his tt. you have all the proof in the world of audio that this is the problem, as you eliminate the result by engaging the subsonic filter. My friend has 3 turntables and they all have feedback/isolation problems but he thinks his equipment is so superior that they can't possibly be the cause.
+1
He's wrong.
If a stylus moves, it will generate a signal. The RIAA playback curve means there's a huge amount of boost at very low and subsonic frequencies, so the signal produced by the cartridge ends up being very large after passing through the phonostage. The IEC proposed an amendment to the RIAA curve to mitigate the problem but it was never widely adopted. Worse still, some phonostages don't adhere accurately to the RIAA specification and actually apply extra boost at subsonic frequencies, making the problem worse.
Well matched arm effective mass and cartridge compliance which puts the arm/cartridge resonance at about 10Hz will help, but there is one other possible solution to the problem and that is arm damping. It is possible to damp the motion of the tonearm at subsonic frequencies and it is very effective at eliminating "cone flapping".
This is the best implementation of arm damping, but there are other ways to do it.
Blue Shadow
Waiting for Vintage Gear from this century
Cone flapping as mentioned above is the result of using a damn turntable for your input signal. Without a low or subsonic filter the table no matter what it is, is going to put crap into the signal at low enough frequencies to cause woofer movement. Some folks like to look at that and think it is cool. Since we hear to about 20Hz any movement slower than 20 times per second we can't generally hear and could be eliminated from the signal to save amp power and woofer movement for what we can hear. If you see the woofer wobbling, it is lower than 20Hz.
You can try to do things to decrease the woofer movement or eliminate it but it will require a filter or damping of some sort. It is just the nature of the beast. Fortunately all this old crap we love so much doesn't sound really terrible when the subsonic filter is used. Some, maybe many can hear the difference, not usually a lack of bottom end as the subsonic filter should be below hearing. The low filter might dip into the music and take away the lowest bass and I don't usually use that one but on units that have the subsonic filter, unless I'm sitting there concentrating on what my equipment sounds like I use it.
It is the nature of the beast and 4 pages in I'm gonna go my own way on this and let you guys fight it out as to the solution. The other day during our field trip the Kiseki Purpleheart on the Brinkman arm on the Brinkman direct drive turntable into the Luxman high end integrated amp as a preamp to the Luxman tube power amp and a pair of Devore speakers has wobbling woofers until we switched in the subsonic filter which as Gadget reported took the sound quality down a notch or three. So you just gotta decide what you want to do. woofer wobble or a subsonic filter ain't going away when you are playing records.
You can try to do things to decrease the woofer movement or eliminate it but it will require a filter or damping of some sort. It is just the nature of the beast. Fortunately all this old crap we love so much doesn't sound really terrible when the subsonic filter is used. Some, maybe many can hear the difference, not usually a lack of bottom end as the subsonic filter should be below hearing. The low filter might dip into the music and take away the lowest bass and I don't usually use that one but on units that have the subsonic filter, unless I'm sitting there concentrating on what my equipment sounds like I use it.
It is the nature of the beast and 4 pages in I'm gonna go my own way on this and let you guys fight it out as to the solution. The other day during our field trip the Kiseki Purpleheart on the Brinkman arm on the Brinkman direct drive turntable into the Luxman high end integrated amp as a preamp to the Luxman tube power amp and a pair of Devore speakers has wobbling woofers until we switched in the subsonic filter which as Gadget reported took the sound quality down a notch or three. So you just gotta decide what you want to do. woofer wobble or a subsonic filter ain't going away when you are playing records.
Last edited:
Not sure what model Infinity's you own but I don't have any problems exhibited like the OP states. I own a quite number of Infinity speakers.
Personally I think it is simply a case of excessive boast of his bass along with the use of the loudness button while using a record. A record doesn't have quite the bass response in most cases like a digital device so many people think they will make do by boasting the region excessively.
I might add, I don't have any tone controls or any loudness buttons on my preamp, so I have no way to boast my bass.
Last edited:
It's not an issue with any of my speakers, but it can be if the turntable is having issues for whatever reason.
My Carver pre has a subsonic filter that when engaged cuts in at 18hz, same with my Kenny, neither are engaged as they're not required.
As you I don't boost (boast lol) my bass with either tone controls or the loudness circuit, run them defeated.
That said I do run subwoofers in the media rm, but once correctly dialed in they don't present any issues with the turntable to cause woofer pumping.
I suppose one way to avoid this, is to keep your grilles on the speaker. Out of sight, out of mind. 
Anyhow, I pulled the grilles off mine. And the woofer movement is most noticeable if I walk heavily (like stomp my feet) directly underneath the turntables. No problems, when music is playing and no heavy stepping by the tables. I have no subsonic filter on my outboard pre-amp (unless it is built-in to the unit). No loudness boost. No EQ. Bass is okay.
Sony's setup = 8-9 Hz resonance (modded Denon DL-103R on SME 3009). Technics = 10 Hz (AT 33Sa on stock 1200Mk2).
Of course, I have two acoustically sealed subwoofers. So, I don't need to boost the bass-end of the music to get good bass --- over-driving the woofers. If that matters.
Anyhow, I pulled the grilles off mine. And the woofer movement is most noticeable if I walk heavily (like stomp my feet) directly underneath the turntables. No problems, when music is playing and no heavy stepping by the tables. I have no subsonic filter on my outboard pre-amp (unless it is built-in to the unit). No loudness boost. No EQ. Bass is okay.
Sony's setup = 8-9 Hz resonance (modded Denon DL-103R on SME 3009). Technics = 10 Hz (AT 33Sa on stock 1200Mk2).
Of course, I have two acoustically sealed subwoofers. So, I don't need to boost the bass-end of the music to get good bass --- over-driving the woofers. If that matters.
Last edited:
JP
7480 74111110101115
A lot of the time sure, but it does depend on the compliance/EM match. I’ve some combos that’ll flap the woofers like mad, and others with no visible movement. Both cases caused by record warps.
JP
7480 74111110101115
I’d have to measure them. I use Technics EPA-500 arms on my main tables. With 5 different EM wands I typically just grab the wand that should work and don’t worry about it. On the combos that aren’t great I engage the 10Hz filter on my DSP crossover.
I was thinking of experimenting a bit. For Example my 150MLX will pump woofer on an 8g wand, so I was going to stick it on a 6g to see how it behaves.
Thunderbox
Super Member
If you can see the woofers moving in and out a stethoscope will not work because it is below your hearing ability.
branden_8091
Member
(deleted)
branden_8091
Member
The KAB RF-1 is just that