Anyone wish they had a rumble subsonic filter?

Hi Hdm. Yes they are ported. And I'm no expert either. Maybe I should contact Kevin as I did Marchand. I still believe that I do not want to attenuate, or mono, any frequencies above 18Hz. And I'm sure you are correct when you say there are high quality and low quality solutions for subsonic crap. I actually have a small problem with my speakers reacting on only certain LPs. They are not flapping all over the place. They are Eton 11 inch woofers, btw, and the cones move very, very easily. That might be compounding my problem.....if indeed it is a problem worth solving! Know what I mean? Injecting additional electronics and ICs to solve something that is more of an irritation than an audible rumble. I'm a little confused, but that's normal in my world:)

240: I think that you will find that when you eliminate this problem from your system that it will indeed sound considerably better. That is certainly my experience. My limited understanding of the problem is that, apart from having your speakers making movements which they are not supposed to (which can't help but effect sound quality if you think about it), the subsonic issue has pretty substantial detrimental effects in terms of amplifier performance and possibly longevity as the amp works its guts out reproducing these ultra low frequencies.

A high quality filter like the KAB or the one David Hadaway sells separately for around $200 will, I think, get the job done in a "high quality way", whereas the cheaper, simple capacitor solution will obviously involve some compromises.

The other alternative, of course is to upgrade your phono stage. I was actually kind of shocked in the past few years when I got back into vinyl that many of the quality phono stages do not include a subsonic filter (alas, that's how I ended up with the KAB), but the designers of these products are looking at things from a purist standpoint and a desire to produce ruler flat frequency response. In the real world, though, particularly with ported speakers, there are many systems that are going to have subsonic issues, which was why, in the end, when I upgraded my phono stage recently I focused only on phono preamps with a high quality subsonic built in.

240zracer...Take Hdm's advice, and get the rumble filter.
Your concern about maintaining stereo separation down to 18 Hz is not reasonable.
1. LP cutting practice (usually) is to mix to mono at low frequency.
2. Many people don't think that LF sound can be localized, hence the popularity of single subwoofers.
3. Although the cut-in frequency of the filter may seem a bit high, remember that its action is gradual, and considerable separation will be maintained well below the stated frequency. Thr filter designers were free to pick any frequency, and they built what worked best.
4. If you don't like it you can easily unplug it.

Hello again, I think the Marchand Bassis is a great unit. Mine is set up after the Marchand XM126 crossover so only the low freq go through it. It has a 20hz filter and a rumble filter of which I find both to be necessary. Also the Bassis eq is very subtle and I believe would be a wonderful addition to your system. It only extends the bass response where your system starts to fall off and you can correct the Q and the bass extension. It works with ported and non ported speakers but is most effective with non-ported. As far as additional equipment and interconnects remember as Einstin said to make things "simple but not too simple". Well here is your solution for several problems, of which, for the most part you are unaware of untill you hear it. You do have rumble and subsonic problems, and they do need to be eliminated. Musical reproduction is like the universe, you always know there is something more out there....
Bob
PS thanks for the compliment on my system. I consider my system minimalist as it only has what is necessary for reproduction of vinyl music. That includes the Bassis which, if you understand it, is a great piece of equipment and is quite reasonably priced. I recommend that you buy it with the stepped attenuators rather than the pots if you do indeed buy one.

OK, guys, and thank you! I now believe I need to solve this rather than ignore it. Going to re-read this thread, visit the websites again, and make couple of phone calls. The one thing my gut tells me not to do, is attenuate above the 20Hz. I just listened to an orchestra recording. In the jacket is a picture. There are no less than five string basses on the far right. There is substancial bass in the far right of the soundstage when I play this LP, and my right amp meter bears this out by showing how hard that channel is working. So I guess I don't believe bass is non-directional. It also sounds like bass will improve overall, by solving the problem and my amp will perform better. Everyone who posted seems to agree on that. That's some really good incentive. Off to the websites......again! And thanks, again.