Unsolvable Woofer Pumping (Phono only)

Send me a link in a PM, the one you've put doesn't allow me to use it. I may be interested

 

You're probably too new and don't have access to the For Sale forums yet. I'll send you details in a PM.

Oh, wait….you are in Canada. I don't ship anything there. Sorry.

 

Because of our outrageous shipping prices? Ha ha.

 

Last time I did that I regretted it. Shipping too pricey, plus doing documentation, etc. FWIW: my ad specifies CONUS only.

 

I don't blame ya...I prefer to ship stuff domestically too. Only thanks to 'Shippo' on eBay have I been more willing to do int'l, as it takes care of the customs for you. Take care!

 

Ok so your speakers should get the full signal from the amp-RIAA-record player. The factors involved are the level of warps of the record, tonearm/cartridge fundamental resonance frequency and the possible LF filtering that the RIAA-preamp-amp have before the signal reaches the speaker. I would be very surprised if there is no warp-related LF signal below 20 Hz going through to the woofer, but the level varies depending on the factors above.

 

I hear no issues at all, and I have no desire to introduce a rumble filter, nor do I need to. Keith Herron also discouraged it when I thought I needed one. I have further improved performance by using both a massive spindle clamp and outer ring (5.5 lbs total). Nevertheless, when I had woofer pumping issues, the biggest improvement came by properly isolating the turnable. Changing my tonearm away from one with magnetic bearings resolved the rest.

And about 2 hours ago I integrated a new amp to the system that has even better bass performance, and I still have no audible issues whatsoever.

 

A very late reply...but just thought I'd follow up for any interested folk.

The problem was!... simply my vinyl. Some records just have subsonic info on them due to the way they were produced (i.e. my copy of Hotel California), whereas other records don't have any.

While I'm happy I have a system that can reproduce these, I don't want it to! Lol...ended up finding a used KAB RF-1 rumble filter as many recommended across a few forums and couldn't be happier. There is no noticeable sonic difference and no more pumping! Hooray!

 

Yup, many are just in denial and can't comprehend this fact. Any substantial collection will have at least a record or two like this.

 

You're welcome! Easy transaction for both of us.

 

Yup. My collection of 4000 LPs has one, just one.

I just recently sold my KAB RF-1 as something completely unnecessary to my system.

 

I have a very old Technics SL-Q2 (40 years), a Graham Slee preamp without rumble filter and monitor audio silver speakers with 90dB sensibility and 8" woofer, rear ported.

My tt stands over a thick marble platform (2cm aprox) and I never see woofer pumping ... only a very little movement (nothing to worry about) on lps with some warp on the edge.
I also have many years listening to vinyl and woofer pumping is not "normal" ... please, test a good and firm base for the tt or check with a better tt, project entry level aren't very good maded. I prefer a good old tt on the same budget.

If you're happy with the filter, that's ok, but you need to know that is not "normal" as some people says, and I agree that you're simply masking the resonance, as others posted before.

 

Woofer and subwoofer pumping from my system was all about wrong crossover point from mains to sub whereby I created a 60 to 80HZ hole. With the frequencies between these points being absent, neither produced by sub or woofers, a pumping like effect was heard. Re-setting the preamp to filter mains at 60 Hz to match preamps 60Hz and below output to sub eliminated the problem.

 

Ok, I never use subwoofer since the 90s, I don't have too much experience with subwoofer in stereo. In 70s and 80s the subwoofer doesn't exists.

On the early 90s, I bought a 5.1 system for movies and music. It was fun, but only 2 years later i left that system only for movies ... the old stereo in good speakers was too much better.

And ... 2 more years and the 5.1 was eating dust ... a good soundbar under the tv was all I needed for movies.

So, I only used subwoofer in stereo a little time and only with digital sources. My lps on boxes, totally hidden ... now the marvel of digital music was all we need

Sell my "precious" Technics 1200 mk5 was really hard, but, what can I do? It was a useless device, right? Dumb, very dumb

When I really discovered that the CDs don't sound better, they scratch and are affected by dust and humidity almost as vinyl ... Oh boy.

I find a really good SL-Q2 and I began to listen to vinyl again. Only in the good old stereo.

So, woofer pumping for me was always that: "woofer pumping" ... not " subwoofer pumping". But, is always resonance, vibrations taken with the stylus, so, maybe a good tt base can help in that case too without the need to change the crossover point, because at last, you're doing almost the same that the rumble filter.

 

Cone flap has been around since Mr. Helmholtz first stuck a hollow pipe in a speaker box. Subsonic filters are the only effective way to deal with the problem which is caused by the vinyl itself. Good call Branden.

 

Jitter was caused by digital technology ... yes, but you can, and you need to maintain this anomaly between certain levels ... or the audio quality will be bad.

You surely will buy products that have that quality, even that exists products like "USB decrapifier" by example.

We're not denying the problem or denying that rumble filters can minimize the problem ... we're talking about in a right vinyl setup the woofer pumping not exists.

I think that must be the goal. If you have bad woofer pumping ... something's wrong.

Bad tonearm / cartridge compliance?
Bad acoustics?
Bad tt isolation?
... and go on.

 

" The woofers in a ported speaker are unloaded below resonance, meaning that they will undergo large excursions with infrasonic information"
John Atkinson, Editor, Stereophile ( January 4, 2009)

 

Ha ha, hey! It was.

 

I tried several different TTs, even recorded into a digital recorder and played it back to rule out any sort of feedback. It's simply just information on the vinyl. Only some records do it.

 

Right ... Do you mean that in 99 % of the time with woofer pumping? That's normal? That my tt without woofer pumping in my aprox 800 records collection is about ... luck?

I don't think so, but maybe I don't have the capacity to explain correctly my position, so, I will not talk more about this.

 

It's possible ... but it's not the extreme situation that the thread owner exposed. I repeat, maybe I cannot explain my point of view correctly ... I closed my opinion on this.

 

ALL speakers are a compromise.
(OK, as a loudspeaker engineer I'd more seriously observe that bookshelf speakers due to their size simply can't be effectively ported very low. So any truly low bass content will tend to make their woofers move at lot, since the port becomes just a hole/leak and the woofer is not loaded any more).

 

Not to mention, blanket generalizations about speakers (ported or otherwise) are mostly unhelpful. My speakers are ported and I’ve never had issues with excessive excursion, no matter what bass material I’ve thrown at them at any volume. Many ported speakers may have such issues, but there are a lot that don’t.

 

As an old timer, it's been very interesting to follow this topic.
I remember back in 1974 I bought my first amplifier it was made by a UK company called Amstrad. It had a switchable "rumble" high pass filter as well as a "scratch" low pass filter. Thankfully I never had to use either of them. That amplifier also had inputs for ceramic (piezo) or magnetic cartridges. . .

 

I experienced this and was mildly curious about it, but since I couldn't hear any difference, I just ignored it.