Rumble

[hoopsontoast]

I have just got my SME M2-9 up and running on the Gyrodec but I am getting some odd rumble issues with lots of LF going to the speakers.
I guess I need a Phonostage with a Subsonic filter/Rumble filter, unless there is something I am missing on the setup...

Its a Michell Gyrodec SE (standard PSU), SME M2-9 with Ortofon 2M Blue (at 1.8g VTF). The phonostage is a Trichord Dino Mk1 with standard PSU.

I never seemed to have any issue with the same TT, Cart but with a Rega RB300.

I get the issue when the cart is on the outside edge of the LP, on the run in and most of the recorded tracks, it does not seem to be as noticeable on the run out at the end of the LP.

[walpurgis]

Sounds like the cartridge compliance is a little high for the arm and warps/ripples in the vinyl are being reproduced. A lower compliance cartridge may raise the resonance enough to avoid the effect. I don't like subsonic filters. They seem to impact on the sound to me.

[hoopsontoast]

The SME M2-9 has an effective mass of 9.5g and suitable for cartridges from 5g-12g, the Ortofon 2M Blue is 7.2g and 20 µm/mN. That gives me a resonance of 8.7Hz, a bit low I guess on the following calculator:

http://www.resfreq.com/resonancecalculator.html

I was looking at the Ortofon Quintet Blue or Bronze, which gives me a ~9.5Hz resonance, a bit better. The Benz Micro Silver/Gold too.

[Oldpinkman]

I'd be really surprised if resonance of 8.7Hz was the problem. And therefore, more importantly, real surprised if taking the resonance up to 9.5Hz fixed it. 20cu is fairly normal "high" compliance, and 9.5g pretty "medium" effective mass. My money is on some other issue. Low frequency record noise is just there - I've never heard a silent record.

Maybe the new arm is just more revealing of low level detail. Record warps are in the 5Hz region or below. You can't hear those. I can't hear those. I'm not sure if whales can hear that lower frequency. (I'm assuming you are hearing it, not just watching it). If you are hearing it, its comfortably above 20Hz - which would suggest too little compliance, insufficient mass. If the mass is too high and the compliance too low it normally manifests as tracking problems - footfall or record warp.

[hoopsontoast]

I can't hear it but I can see it on the bass drivers. When playing music the bass is quite indistinct, I put that down to the bass drivers trying to reproduce other much lower notes.....

[walpurgis]

Have you got a lower compliance cartridge you could try?

[hoopsontoast]

No I don't, I did have an Ortofon MC10 Supreme but I broke the cantilever off it, I've kept it as I can still use it as trade in against the current Ortofon MC range (hence interest in the Quintet range).

[Oldpinkman]

As I understand it, you didn't have the same problem with the RB300 with an 11.5g effective mass and a calculated resonance with the same cartridge of 8.3Hz

There is an elephant in the room. It's not likely to be a mechanical resonance issue.

I have used a Goldring 1022 in the FXR without issue and that has got to be in the same ball-park.

[hoopsontoast]

Correct, I did not notice anything with the RB300 (in the past year or so of use).

[daytona600]

add mass to the headshell or same price as the blue change to a quintet red lower Cu

[DSJR]

The Gyrodek isn't the most stable of suspended decks and it's nigh impossible to get a proper bounce as I know it to be as per Linn and Thorens for example. It's more like a wobbly jelly most of the time I remember. The 2M Blue is a pain as well to set up and far more tricky than the Bronze I feel from experience.

Please make sure you've done the best you can with the Gyro suspension, make sure the arm is correctly fitted and the cable is correctly dressed and then try a different cartridge or stylus if that's at all possible.. May be a good time to try a DL110 at first, before changing your phono stage...

[Oldpinkman]

Ah. There's your answer. Change the Gyrodek for a Pink Triangle where it is a doddle to get a perfect bounce every time.

Adding mass at the headshell is not going to help if the cartridge is too compliant (I don't think it is, but adding mass would only make it worse). Critically, the cartridge is the same, the arm has an almost identical mass to the one that wasnt a problem, so mass/compliance resonances are likely to be a red herring

Maybe DJSR is right and its poor suspension set up...

[hoopsontoast]

Thanks, I shall have another look over the suspension setup and check everything is level and nicely bouncy.

[hoopsontoast]

I have checked over the bounce/setup. Its nice and level, with even bounce (not from side to side when pushed down) although it is easy to interfere with the record by tapping the cabinet that the TT is placed on (right now its on a granate chopping board, with sorbathane feet between that and the cabinet).

I have checked the bearing oil and seems fine, the bearing was slightly loose so thats been tightened, and the platter is secure on the bearing (no play). The armboard is nice and secure with the earth cable(s) attached where they should.

I think it could be interference from something as although walking about does not seem to affect it (concrete floors).

I have done a quick video, showing the problem and that cone wobble seems to be very regular through the whole side of the LP (tested multiple LP's). The level is on the higher side of what I usually listen to but by no means loud in overall terms.


https://www.youtube.com/watch?v=qJAUhx-4yOA&feature=youtu.be

[walpurgis]

I still feel trying a lower compliance cart may throw some light on the situation. Is there nobody who could lend you one? I'm fairly sure there are AOS members in your neck of the woods. Maybe somebody could assist.

[dantheman91]

I have checked over the bounce/setup. Its nice and level, with even bounce (not from side to side when pushed down) although it is easy to interfere with the record by tapping the cabinet that the TT is placed on (right now its on a granate chopping board, with sorbathane feet between that and the cabinet).

I have checked the bearing oil and seems fine, the bearing was slightly loose so thats been tightened, and the platter is secure on the bearing (no play). The armboard is nice and secure with the earth cable(s) attached where they should.

I think it could be interference from something as although walking about does not seem to affect it (concrete floors).

I have done a quick video, showing the problem and that cone wobble seems to be very regular through the whole side of the LP (tested multiple LP's). The level is on the higher side of what I usually listen to but by no means loud in overall terms.


https://www.youtube.com/watch?v=qJAUhx-4yOA&feature=youtu.be


Hi Rob

Whats the track playing in the video i quite like it. Are you shore its not the lower bass notes in the track do you have a digital version to try see if the same thing happens? Seems odd its doing it on concrete floors i used to have the problem with suspended floors :rolleyes: i dont know my old mate you'll work it out.

[hoopsontoast]

Hi Rob

Whats the track playing in the video i quite like it. Are you shore its not the lower bass notes in the track do you have a digital version to try see if the same thing happens? Seems odd its doing it on concrete floors i used to have the problem with suspended floors :rolleyes: i dont know my old mate you'll work it out.

The track is by Daft Punk, "Give Life Back to Music" off Random Access Memories. Its certainly not there on the CD, its on the run in and to slightly less extent, on the run out part of the LP as well as all the way through. It does this on other LP's so I am 99% sure its not in the music.

[Macca]

Can't play the video as I'm at work but I would say almost certainly that this is acoustic feedback - bass from speakers > excites suspended floor > excites TT suspension > excites arm/cartridge and then you get a progressive loop.

Much more isolation for the TT (wall shelf?) and/or the speakers is required. Or move to a room with a concrete floor.

[aniki]

Change the Gyrodek for a Pink Triangle where it is a doddle to get a perfect bounce every time.

FFS! Does it ever stop?


I never seemed to have any issue with the same TT, Cart but with a Rega RB300.

I agree that I don't think it is a compliance issue; the subsonic effects look too extreme. Looks more like a microphonic effect to me.

Do you have another arm lead to try?
Can you try the arm on a different deck?

[helma]

Put on the grilles and you won't see the pumping ;) Seriously though, IMO a sub sonic filter is always a good idea with vinyl and a good implementation shouldn't really affect the sound quality (and doesn't in my experience), but then again I feed on 40 year old equipment. However, you really can't completely eliminate subsonic noise at the source, even with a 'perfect' setup, there's always going to be some. On your video it does look a bit excessive though, so maybe the cantilever is in a constant state of excitement for some reason, but I think this would mostly happen on bad compliance mismatch or with very warped record. Out of whack azimuth could also create symptoms like this, so I'd double check that the azimuth is level and the cantilever is not twisted / the diamond mounted in an angle. Whatever is going on I hope you get it sorted out to your satisfaction.

Just for kicks I tried this on two turntables and without the subsonic filter and volume high enough I get woofer pumping after each record warp for example, we're talking about a very slightly warped record here, but this only happens once every revolution. No action to speak of when there's nothing for the cantilever to get excited about.

[hoopsontoast]

Can't play the video as I'm at work but I would say almost certainly that this is acoustic feedback - bass from speakers > excites suspended floor > excites TT suspension > excites arm/cartridge and then you get a progressive loop.

Much more isolation for the TT (wall shelf?) and/or the speakers is required. Or move to a room with a concrete floor.

The room does have a concrete floor. The thing is it starts before there is anything on the record, on the run in, and thats a 180g LP that's as flat as I can see.


FFS! Does it ever stop?

I agree that I don't think it is a compliance issue; the subsonic effects look too extreme. Looks more like a microphonic effect to me.

Do you have another arm lead to try?
Can you try the arm on a different deck?

I have another phono cable coming soon. I do not have another TT, Cart or PhonoStage to try.

[Macca]

The room does have a concrete floor. try.


Okay - scratch that theory then. :)

[aniki]

I have another phono cable coming soon. I do not have another TT, Cart or PhonoStage to try.

OK, just trying a process of elimination here. How do you have the phono stage set? I would imagine 47K loading & 48db gain?

[hoopsontoast]

OK, just trying a process of elimination here. How do you have the phono stage set? I would imagine 47K loading & 48db gain?

Hi Yes, all DIP switches are 'off' on both L&R, Set One and Two which I believe means 100pF/47Ohms and MM High 48dB (3-5mV).

[Oldpinkman]

FFS! Does it ever stop?



I agree that I don't think it is a compliance issue; the subsonic effects look too extreme. Looks more like a microphonic effect to me.

Do you have another arm lead to try?
Can you try the arm on a different deck?

I believe you can buy a sense of humour from most good online retailers :)

[Spectral Morn]

Can't play the video as I'm at work but I would say almost certainly that this is acoustic feedback - bass from speakers > excites suspended floor > excites TT suspension > excites arm/cartridge and then you get a progressive loop.

Much more isolation for the TT (wall shelf?) and/or the speakers is required. Or move to a room with a concrete floor.

That's what I thought too but Rob says he has concrete floors. However what is it sitting on? If a proper hifi table then is it in the corner, near a room boundary ? Are the walls boast or solid. If its on a heavy cabinet then that might be storring low level resonances from the speakers and exciting the bass cones. I have the Daft punk lp so I will try it myself.... I suppose it could be a pressing fault.



Regards Neil

[hoopsontoast]

That's what I thought too but Rob says he has concrete floors. However what is it sitting on? If a proper hifi table then is it in the corner, near a room boundary ? Are the walls boast or solid. If its on a heavy cabinet then that might be storring low level resonances from the speakers and exciting the bass cones. I have the Daft punk lp so I will try it myself.... I suppose it could be a pressing fault.



Regards Neil

Its sitting on a Ikea Expedit, the same the Gyro was on with the RB300.

Its most certainly not on the recording, I have tried other LPs and its there too, and thats on the run in and run out of the LP.

[Oldpinkman]

Can you refit the RB300 and confirm that it isn't doing it with that arm? Or have you sold that on?

I didn't buy the effective mass theory because the SME is near identical to the Rega in that respect

I don't buy footfall for the same reason - its the deck and not the arm that would be affected - unless as DSJR said its set up, but you say its not. And the deck hasn't changed. And for all my failed attempt at humour about getting a PT instead (thanks Aniki) I believe the Gyrodek a competent enough design in that respect.

[Stratmangler]

I have checked over the bounce/setup. Its nice and level, with even bounce (not from side to side when pushed down) although it is easy to interfere with the record by tapping the cabinet that the TT is placed on (right now its on a granate chopping board, with sorbathane feet between that and the cabinet).

I have checked the bearing oil and seems fine, the bearing was slightly loose so thats been tightened, and the platter is secure on the bearing (no play). The armboard is nice and secure with the earth cable(s) attached where they should.

I think it could be interference from something as although walking about does not seem to affect it (concrete floors).

I have done a quick video, showing the problem and that cone wobble seems to be very regular through the whole side of the LP (tested multiple LP's). The level is on the higher side of what I usually listen to but by no means loud in overall terms.



Looking at the video I have a question.
Are the speakers concerned bass reflex?
I have seen this before with bass reflex speakers. No LP playback is going to be without low frequency output, and the nature of bass reflex speakers is to reinforce low frequency output.
What you're seeing is low frequency output that you in the main cannot hear.

[Spectral Morn]

Its sitting on a Ikea Expedit, the same the Gyro was on with the RB300.

Its most certainly not on the recording, I have tried other LPs and its there too, and thats on the run in and run out of the LP.

ummmm, I am not a fan of that solution, ok for a few TTs but not others. However is it level ? Are the legs nice and tightly screwed in. Have you fitted spikes to the underside of the legs to permit levelling ? Does it sit on carpet or laminate ?

Is the arm cable dressed well, so it doesn't interfere with the bounce ?

So you put a record on, lower the arm and the cart just sitting on the record not playing causes this speaker vibration ? Or is it playing lead in groove ? Do you wait for the suspension to settle before lowering the tonearm ?

Sorry for asking so many questions, just need to get a sense of what is happening.

Properly set up Gyro should bounce evenly up and down with no or very little side to side movement.


Regards Neil

[hoopsontoast]

Can you refit the RB300 and confirm that it isn't doing it with that arm? Or have you sold that on?

I didn't buy the effective mass theory because the SME is near identical to the Rega in that respect

I don't buy footfall for the same reason - its the deck and not the arm that would be affected - unless as DSJR said its set up, but you say its not. And the deck hasn't changed. And for all my failed attempt at humour about getting a PT instead (thanks Aniki) I believe the Gyrodek a competent enough design in that respect.

Just re-fitted the RB300 with the Ortofon and its doing the same. It does seem to be less noticable towards the inner of the disk but its still there.


Looking at the video I have a question.
Are the speakers concerned bass reflex?
I have seen this before with bass reflex speakers. No LP playback is going to be without low frequency output, and the nature of bass reflex speakers is to reinforce low frequency output.
What you're seeing is low frequency output that you in the main cannot hear.

Yes, I see/hear that but this is a regular output through out the whold side of multiple disks, and its reducing the bass definition of the music, sort of muddy bass on all the songs.


ummmm, I am not a fan of that solution, ok for a few TTs but not others. However is it level ? Are the legs nice and tightly screwed in.

Is the arm cable dressed well, so it doesn't interfere with the bounce ?

So you put a record on, lower the arm and the cart just sitting on the record not playing causes this speaker vibration ? Or is it playing lead in groove ? Do you wait for the suspension to settle before lowering the tonearm ?

Sorry for asking so many questions, just need to get a sense of what is happening.


Regards Neil

The Gyrodec is nice and level, legs are screwed in. The thing is there is no movement walking around, certainly nothing moving enough to move the TT/Cabinet.

[Spectral Morn]

I meant the table not the turntable and the other questions I asked would help if answered - thank you.


Regards Neil

[hoopsontoast]

"Is the arm cable dressed well, so it doesn't interfere with the bounce ?

So you put a record on, lower the arm and the cart just sitting on the record not playing causes this speaker vibration ? Or is it playing lead in groove ? Do you wait for the suspension to settle before lowering the tonearm ? "

I have tried it with the cable loose and tied up and it makes no difference.

This effect is happening on the lead in, it does not do it when the needle is on the record but not spinning.
The suspension is as settled as it can be before I use the arm lift to lower it down.

[Spectral Morn]

"Is the arm cable dressed well, so it doesn't interfere with the bounce ?

So you put a record on, lower the arm and the cart just sitting on the record not playing causes this speaker vibration ? Or is it playing lead in groove ? Do you wait for the suspension to settle before lowering the tonearm ? "

I have tried it with the cable loose and tied up and it makes no difference.

This effect is happening on the lead in, it does not do it when the needle is on the record but not spinning.
The suspension is as settled as it can be before I use the arm lift to lower it down.

Ok thank you.

Is the headshell level viewed front on ? Is the cartridge aligned right, cantilever straight relative to the groove.

Is there any up and down motion looking at the platter straight on ?


Regards Neil

[hoopsontoast]

Ok thank you.

Is the headshell level viewed front on ? Is the cartridge aligned right, cantilever straight relative to the groove.

Is there any up and down motion looking at the platter straight on ?


Regards Neil

Yes, the Azimuth is correct.

I tried it again with another LP, this one is basically brand new and absolutely dead straight and its still doing the same on the run in, but again less on the run out at the end.

Only other thing is that for a good while I have been using some Keesonic 701a which I never noticed it on, although I used the grilles on most of the time and they don't have the deepest of bass. Now I am using the Kord Tornado and the Volt Bass driver has a low fs (around 30Hz) which might make a difference?

[Spectral Morn]

I wondered re alignment as a badly aligned or cart with a damaged cantiliver might cause this as it tracks the groove poorly.

I am stumped :scratch:

Have you a chopping board to hand granite etc or wood ? Try putting it on the table and the turntable on top. If you have squidgy domed feet put them at the four corners of the board. I am still thinking this is to do with what its sitting on.


Regards Neil

[walpurgis]

I didn't buy the effective mass theory because the SME is near identical to the Rega in that respect

I still feel the opposite may be true. The effective mass may or may not be that close. It could depend how the arm mass was calculated.

Looking at the video, The sequence of cone tremors appears possibly cyclic at say 33 1/3 maybe? That suggests to me that it likely is a compliance mismatch producing too low an arm/cart resonance picking up record warp and rippling. No record is truly flat. Oh and it does not matter whether you are into the music grooves or not. The cartridge will still reproduce warp.

The suggestion that this is more pronounced at the outer edge of the record reinforces my opinion. The amplitude of warp will probably be greater here.

Just buy a cheap lower compliance cartridge and try it!

[hoopsontoast]

Neil, the Gyrodec is already on a Granite Chopping Board, and then sorbathane feet below that and the Ikea Cabinet.

I am thinking now, like on the first page and above to try a lower compliance cartridge, although as mentioned it was doing the same on the RB300.

For tonight, I have just put a CD on :doh:

[Spectral Morn]

Neil, the Gyrodec is already on a Granite Chopping Board, and then sorbathane feet below that and the Ikea Cabinet.

I am thinking now, like on the first page and above to try a lower compliance cartridge, although as mentioned it was doing the same on the RB300.

For tonight, I have just put a CD on :doh:

Ok that wasn't clear.

Try taking these out from underneath the Gyro then.


Regards Neil

[hoopsontoast]

Ok that wasn't clear.

Try taking these out from underneath the Gyro then.


Regards Neil

I had it without them originally when the problem was noticed. I put them in yesterday.

[Macca]

How far away is the TT from the nearest speaker? Could be acoustic feedback I think that was what Chris was suggesting. I've seen that with bassy speakers before.

[walpurgis]

By the way, if there is no subsonic filter and the arm/cart combination have a low enough resonance, the undulations of record surfaces will be reproduced. This is certainly more visible in reflex type speakers as the cone is being asked to reproduce signals well below system resonance and there is little resistance to cone movement which just displaces air via the bass port. The Celestion Ditton 25 and 66 speakers were often displayed at exhibitions doing exactly this, with the big, long throw bass cone and ABR cycling back and forth out of phase with each other, just for visual effect.

[hoopsontoast]

How far away is the TT from the nearest speaker? Could be acoustic feedback I think that was what Chris was suggesting. I've seen that with bassy speakers before.

This is the setup (sorry for the crap photo and not showing the granite chopping board).


http://i46.photobucket.com/albums/f128/hoopsontoast/IMGP2266_zpsgpx2ftm2.jpg (http://s46.photobucket.com/user/hoopsontoast/media/IMGP2266_zpsgpx2ftm2.jpg.html)

[walpurgis]

Shame you're not nearer. I'd pop round with a ZYX R50, which is lower compliance and we'd see what happens.

[Spectral Morn]

That I think is your problem not a suitable thing to site a record player on in my opinion, and its in a corner and quiet close to the speaker. Wall shelf would help isolate the turntable but its still in a corner which isn't ideal re air borne vibration.



Regards Neil

[Macca]

That I think is your problem not a suitable thing to site a record player on and its in a corner and quiet close to the speaker. Wall shelf would help isolate the turntable but its still in a corner which isn't ideal re air borne vibration.



Regards Neil

I'm going to agree, not because I know a fraction of what Neil does about turntables but because I've had the same problem many years ago. TT out of the corner and away from the speakers - preferably behind them,

[hoopsontoast]

I shall have a look into a wall mount as well then :)

[Oldpinkman]

At the risk of having aniki jump down my throat again, I could site my pt there and it wouldn't bat an eyelid. Except that it is on a flimsy wood wall shelf, it effectively is sited there.

Have I read this right? The problem arose when you changed arms, but when you changed back it's still there. You also changed speakers.

There must be a strong case this is not faulty and just picked up by the new speakers, and so you are noticing it. When you say this bass cone wobble you can see spoils bass reproduction, what are you referencing against?

[awkwardbydesign]

Why not temporarily put the speaker(s) as far from the deck as possible and see what happens?

[Oldpinkman]

I've had a word with the ju-ju man

In summary

If you have hit the high Q point it will wobble. Simples. (Every system has a high Q point - yours is a visible but inaudible 9Hz roughly. You have to have one somewhere. Lower than that and record warps and footfall will be a problem. Higher than that you can hear it. But you can't not have one)
More often than not, Wobbling cones are to do with an unloaded drive unit = Reflex. (It is the change of speakers, not the change of arm caused the observation)
And we are talking sub-sonic so, well below resonance and hence fully unloaded. (Still the speakers)
Rumble of course makes things worse.

Still, however, mulling over why the SME and Rega behave differently...they really are very similar in this regards... (And actually, turns out they don't behave so differently)

Run-out and run-in...hmmm..maybe when they cut records, they don’t take as much care at the extremes because there is no music, so the plastic is not as flat as the modulated sections, which gives rise to more LF than the rest of the record? (Nah Arthur - clutching at straws)


Hope that helps :)

[walpurgis]

More often than not, Wobbling cones are to do with an unloaded drive unit = Reflex. (It is the change of speakers, not the change of arm caused the observation)

The cartridge will not reproduce record warp if its compliance is correctly matched to the arm. Below arm/cart resonance the stylus suspension will act as though it is near rigid and though the arm may follow warps, the stylus cantilever suspension will not to any great degree, so there should be no significantly wobbling cones.

[Oldpinkman]

The cartridge will reproduce a record warp as well as it will a violin harmonic.

The issue about correct matching is the frequency of input which will cause the greatest movement. The point about the mechanical system resonance is it is the frequency where very little input causes lots and lots of output.

Both arms with that cartridge have the same (roughly) resonance. And we have now established both arms cause the same effect...

...when the speakers are changed to a Reflex design.

If you put a lower compliance cartridge on and get a system resonance of say 13Hz you will just watch a faster wobble. And, maybe hear it more if the harmonics are at correspondingly higher frequencies.

The problem arose when he changed speakers, not arms. He just happened to change both at the same time. A bit like , as I referred to on TAS, when I made up a new set of cables for the Pip / Benchmark as fully balanced using starquad cable, and auditioned with the speakers too close to the wall. I had changed too many variables at once.

You can't not have a mechanical resonance. You can just move it about a bit (say from 9Hz to 13Hz) but there is still going to be a frequency at which there is MUCH more output. Its the old heavy rubber on a bendy ruler stunt - change the weight of the rubber and you change the frequency at which you can keep the ruler wobbling, but you can still always find a frequency at which the ruler wobbles, with a barely perceptible movement of the hand to keep it going.

Pick your frequency - below 6Hz and you are likely to get tracking issues. Above 15Hz and you will probably hear it .

Edit: Of course - it is easier to SEE lower frequencies - so if you shift the resonance higher, you may hear it, but may not notice it visually - you would have to feel the speaker cone with your hand.

[Barry]

No - if the arm/cartridge resonance lays in the range 8 - 12Hz, the cartridge will not reproduce record warps (~ 0.55Hz), for the simple reason that below resonance, the arm and cartridge cantilever move as one: there is no differential movement, so an output cannot be generated.

An abrupt warp (a bit like a speed bump) will act like a transient and cause the stylus to 'ring' with a frequency of several hertz, which if high enough and close to the arm/cartridge resonance will be amplified by the resonance. Depending on the Q-value at resonance, this unwanted signal will be reproduce by the system. An obvious solution is to either fit a FD200 damping dashpot to the SME M9 arm and/or use a steep high-pass filter with a turnover frequency ~ 20Hz.

[dowser]

I assume it affects both bass cones? I would disconnect speaker closest to tt to see whether it is acoustic feedback related, I think it will be.

[hoopsontoast]

Upon some more testing:

The effect is worse at the start of the record, especially with more warped records although it does do it noticeably with flat records and always seems to be the same rhythm/resonance.

I have tried it with multiple albums, same effect.

It affects both speakers, I have tried with just the one furthest away playing and it still shows on that speaker.

The issue is the same with the 2M Blue on both the RB300 and M2-9.

I have not tried the old speakers yet, I may not have noticed as I have the grilles on the old speakers 99% of the time.

[struth]

i had similar problems when i used a orofon vms30 cart with my set up. I put it down to a mismatch between cart and arm/tt type. only cart ive had trouble with actually and there was nowt wrong with any of the gear or cart. I think the blue is a similar cart to the vms in many ways or so i was told.

[Macca]

is this still rumbling on.... ? ;)

Are you sure it is actually affecting sound quality? if it is just a bit of woofer excursion at the start of the album I'd be tempted to forget about it.

[hoopsontoast]

Well some more work....

Bought an AT33PTG/II and its still doing it but seems only to show it on warped records, and near the start of the record.
It also seems to be most noticable on my 180g records, which seem more warped than most of my older normal ones.

So maybe a rumble filter may well help if the warp resonance is very low frequency?

On the plus side, very impressed with the AT33PTG so far, even new out of the box its very open and detailed without being bright.

[helma]

So maybe a rumble filter may well help if the warp resonance is very low frequency?


Yes it probably would - I'm assuming though you mean subsonic filter, which usually starts to cut off around 15-20Hz as opposed to those rumble filters present in very old vintage gear, with cut-off frequencies well in the audible range, designed to be used with crappy old TTs with all sorts of motor hum and bearing noises coming through in the bass range. Don't get one of those :D

Some people seem to be against subsonic filters feeling they have negative influence on the sound quality and bass response, but I've never heard this in my system and a good filter won't do much if anything to frequencies over 20Hz. Of course it might be my system is just not revealing enough or I've been very lucky with my phono stages :)