Two good things (relatively) about low frequency noise playing records:
1) I find it less offensive during listening than high frequency noise
2) If you can see the woofs on speakers, you can be sure when it exists because you can see and/or feel it perhaps even easier than you might hear it. |
I've seen or been able to feel (to the touch) unwanted low end woofer excursions in smaller bookshelf/monitor speaks I've owned in the past during record playback that on paper could not produce subsonic frequencies.
This tells me that the unwanted signal was not subsonic, yet still undesirable in terms of reproducing unwanted low frequency noise often associated with record playback that one would ideally prefer to not exist.
Despite having access to low in addition to subsonic filters available, my choice was most always to not apply low (high pass) filters that would also negatively impact the real music signal in that range of the audio spectrum.
Effective isolation, clamps, etc. are probably more effective ways of dealing with low end noise introduced during playback of warped records, etc. without impacting the music. |
If your record is warped or cut too poorly to deliver satisfactory sound, even with filters, clamps, etc., then you have two practical options:
1) get a better pressing of the record
2) buy the CD or digital equivalent if possible.
Unless the tt is not operating properly, that is seldom the cause IMHO.
Low end noise, audible or not, is one of the inherent banes of vinyl.
That's just the way it is. |
"I say, why not put the filter in, if it is a problem. If you don't hear it, don't worry about it."
Agree. It's not illegal. If it works for the better for you, then you should do it.
BTW the other common negative effect I've seen with rumble and other types of low frequency noise, is that even if it is not audibly disturbing to someone , the fact is it uses up significant amplifier power to produce noise. This can result in the amp clipping and damaging the speaker. Ironically, the low frequency noise usually ends up damaging the tweeter first, at least in most cases that I have observed over the years. |
Eldartford,
I am in agreement with your perspective on these things. |
Ptmconsulting,
It hasn't been a burning issue for me either. It is what it is. You either live with it or there are ways to deal with it both physical (clamps, new records, CDs instead) or via signal processing (filters, etc.).
On the signal processing front, when it comes to dealing with complex signal processing issues like this, technically, a lot more can be done in the digital domain than in the analog, but it is a complex undertaking and not one I would recommend for the uninspired. |
Ptmconsulting,
Not me, but I just thought it ironic that technically the most practical way to clean up a messy analog signal off a turntable were one so inclined might be to convert it to digital first before doing the processing.
The horror! The horror!
Still, DCS and other companies do some truly magical things in the digital domain!
Cheers! |
Maril555,
I'd start with the production quality of the record being played especially if the problem does not occur with the table running and no record playing or it is obviously variable from record to record.
If it is the table (is that a direct drive model?), maybe try a mat with better isolation. |
Markpao,
Best to minimize it as much as possible through better isolation, clamps etc., in that large driver excursions from noise can cause damage more easily than otherwise, and it consumes power to produce noise that might result in amp clipping and tweeter damage sooner, , but it is normal, in lieu of filtering, to always have some of this present with records.
Its something to be aware of, keep an eye on, and manage, but not expect to do away with completely even with high pass filtering. |
Maril,
I notice in your pic that the table sits close in from of on of the speakers. That may be a challenging location unless the floor in your listening room is extremely rigid, like a concrete foundation or such and same true for your stand.
If you can as a test , you might try locating the table behind the speakers for better isolation.
Unfiltered, on most good systems, most records will produce some movement in the woof and possibly the mid-range as well depending because few if any records are cut perfectly or are perfectly flat resulting in low frequency noise.
Relocating the table better and using a record clamp might be two easy things to try to reduce the effect.
Visible driver movement is often associated with the specific record itself. In this case, the patterns and magnitude of movement will vary from record to record.
If the problem is due to vibrations from the table motor system being picked up, I would expect little variability in pattern and magnitude from record to record.
If motor vibration is the source, it would probably persist the same regardless of tt location and specific record playing and this may require servicing of some sort for the table to fix if possible. |
"Perhaps you would like them better if the came in a 20 pound one foot square box with a ton of wires and capacitors and resitors and tubes and...:)"
Isn't that necessary to qualify as high end? |
" I think I'm leaning more toward living with it than putting something else into the signal path that might negatively impact the rest of the sonic spectrum"
Sounds like a good approach.
I know the positive attributes of vinyl and analog is worshiped by many here, including me to a significant extent, but it is what it is, almost a form of antique collecting at this point, and like most things it ain't perfect.
It only bothers me when I have some old rare favorite record that has particular issues and can't be replaced easily, but in most cases, I can either find a decent fresh replacement that is better somewhere either on vinyl or CD. |
Maril,
Yes, it is a valid concern worth investigating. |
FWIW, some speaker manufacturers build subsonic filters into their speaks as a way of tightening up the low end by filtering out low end frequencies that the speaks are not designed to reproduce accurately. That is another possible reason why some do not observe this phenomena on their system. It is a true statement though that it is inherent to the medium. For example, I believe Ohm does this with newer design speakers that employ their "sub bass activator" circuit internally. |
Eldartford,
I've seen the Ohm sub bass activator device. It is a rectangular circuit board just a few inches in dimension that connects between crossover and woofer internally as I recall. I ordered a pair and installed them into my Ohm L's as an upgrade. The cost was nominal as I recall, less than $100.
My understanding is that it acts as a subsonic high pass filter to some extent. It definitely helped clean up and tighten the low end on these moderate sized bookshelf speakers.
Here;s the description of the SBA upgrade on the Ohm site:
"Tighter and deeper bass is heard with the addition of a SubBass Activator (SBA) and vent adapter. The SBA eliminates the drive below the speaker's natural response to reduce distortion and clean up the deep bass. The vent adapter tunes the cabinet to work with the SBA and new woofers for deeper bass response. " |
in 100% of the cases I've seen over the years where "rumbling" or "pumping" was a significant issue at play, the cause was a warped or poorly cut record.
Lets face it, even if our turntables and systems are darn near perfect, few if any records are. Some are real bad. You'll hear the effects of a poorly manufactured record way before the stylus starts skipping grooves, especially with most good turntables that track very well.
If you are playing a record and getting a lot of pumping or rumbling visible with your speakers, just be glad that your table is such a good tracker and accept the fact that this is par for the course. Either that, or go for the filter if it is something that cannot be lived with. |
I do suspect some cartridges with higher compliance (stiffer) styli might be more naturally immune to picking up low end noise due to record warping or irregularities in the way the record grooves were cut (off center, etc.). |
04rdking,
YEs, I got it backwards I think.
I did mean "stiffer" which I believe is in fact lower compliance. |
"I believe that all LP systems would benefit from 20z (subsonic filtering)"
If done right, I would tend to agree. |
It depends on whether what's happening below 20hz is related more to the music or noise. Best to eliminate the noise first if possible. |
There is no doubt that thinner vinyl is more susceptible to warping and that warped records will result in subsonic noise that can cause a subwoofer driver to pump wildly if transmitted and not filtered somehow. A cartridge with lower compliance stylus might be more immune to the problem, but the best solution is to replace the record with a better copy when this occurs (or get a good digital copy if not allergic to digital). |
Stevecham,
Probably because it would raise costs and even perhaps make the product less appealing to high end purists who do not like any extra circuitry mucking with their signals.
I do find also that it is less of a real problem with many higher power modern amps these days that have the guts to be able to handle the low frequency noise in most cases (decent record pressings) without clipping so there is little audible effect and lower risk of causing damage to the speaks.
I mostly listen on my OHMs where the driver is contained within a metal mesh cage so I can only listen for subsonic issues, not see them. I have to go to my more conventional Dynaudios if I want to look for a pumping woofer. Practically, it has not been an issue worth worrying about for me. |
