Phono Stage upgrade to complement Dohmann Helix One Mk 2

Lew, the high pass is made it at the input of my amps ( cap/resistor ) the low pass is made it by the Velodyne electronics. Maybe you can do the  same or look for a second hand Bryston croosver.

In the link I just posted you can read about 12"/15" drivers characteristics inside the same catalog models.

After last week’s talk about a system I find ^this^ humerous.

 Lastly, if you don’t have a subwoofer or preamp output on your amp or preamp, subwoofers such as the RELs we sell have a specific high level input which runs off your amplifier’s speaker binding posts.

There is a certain simplicity and elegance in running the sub input off of the speaker’s binding posts. Not sure if it is just REL and Vandersteen, or if there are others as well.

Is there a "best" approach for monoblock amplifiers with two sets of binding posts?

I’m not sure I understandI?

I am guessing that the speakers have bi-wire posts?
So it sort of depends on whether you 4 sets of wire pairs, or a bundled bi-wire and whether it is a single end at the amp, or if there are two set of ends… and whether they can splay wide enough to hit both sets of outputs.

Thanks for the info, Raul.  You remind me that long ago I did consider just adding a capacitor in series with the input of my main amplifier, to create a Butterworth type hi-pass filter.  That still seems the least harmful way to do it. I calculated a .02uF capacitor (or two per channel for my balanced amplifiers) would do the trick for my amps, with an 80Hz flex point.

Holmz, I am no fan of the REL approach, for the reason that if you drive the subwoofer off the main amplifier output, then neither the main amplifier nor the main speaker derives any benefit in terms of reducing the workload inherent to reproducing the lowest bass frequencies. Moreover, any distortion in the output of the main amplifier is presented to the REL subwoofer amplifier at its input. Unfortunately, I long ago concluded that you cannot obtain all the major benefits of subwoofing unless you're willing to add a high pass filter on the main amplifier.

Holmz, was that "humerus" or "humorous"?  And why did you find it humorous?

@lewm

I suppose this means that your preferred approach would be to use both the XLR and RCA outputs from the pre-amplifier: one set for the monoblock amplifiers, and one set for the subwoofer.

If that’s the case, then it seems like my pre-amplifier would need a low pass and high pass cut off for the speakers to receive their proper signal and the subwoofers to receive their proper signal. Of course, another option would be to run the pre-amplifier signal through the subwoofer, which would be designed with low pass and high pass filters, and that signal would then pass to the amplifier to the ESL speakers. But I would think that this latter approach could degrade the signal going into the amplifier and ESL’s. It might be a no-win situation. . .

Holmz, I am no fan of the REL approach, for the reason that if you drive the subwoofer off the main amplifier output, then neither the main amplifier nor the main speaker derives any benefit in terms of reducing the workload inherent to reproducing the lowest bass frequencies.

Well I am not sure what the REL approach is other than reading @Rauls words that it derives the input from line level rather than RCAs or XLRs. So it sounded like the it was similar to a Vandersteen, however the manual is a bit light light on specifics… other than that there are the speaker inputs.
But whether the main amp to speakers are high pass filtered did not pop out.
It was 30 pages and i skimmed it, so maybe I missed it… but it does seem like it is not the same as how the Vandy unit works. That unit HPF the main speakers, and then the sub rebuilds the bass back up to where it should have been without a HPF going to the main speakers.

Moreover, any distortion in the output of the main amplifier is presented to the REL subwoofer amplifier at its input. Unfortunately, I long ago concluded that you cannot obtain all the major benefits of subwoofing unless you’re willing to add a high pass filter on the main amplifier.

Well that is what I posted a while ago, and it was a high pass filter to derive that benefit that you point out.
Then the sub rebuilds the signal back to where it should be at.

One can roll their own capacitor, or use a host of HPF to do that at various price points from a capacitor to a Harrison labs one at $50 to ones at kilo$...

Holmz, was that "humerus" or "humorous"? And why did you find it humorous?

I read too much Homer in my youth, as I had a great 7th and 8th grade literature teacher. And hence the spell checker is Greek to me.

I truly did wonder why you thought Raul’s quote was humorous. Along the way, I could not resist the anatomical pun. However, I do know that autocorrect is a bitch.

My understanding of the classic REL set up is that the signal to the REL subwoofer is derived at the interface between the main amplifier and the main speaker. That full range signal is routed to the input of the REL subwoof amplifier which has a low pass filter before its input. The REL subwoof thus augments the main speaker at very low frequencies. This method does not result in reducing the bass frequency burden on the main amplifier or even the main speaker. Perhaps I’ve got it wrong. I suppose all this belongs on another forum, but drbond seems interested, and he is the originator of this thread. Otherwise, sorry for the digression.

drbond, The classic approach is to drive an electronic crossover from the preamplifier.  The electronic crossover has built in active high and low pass filters, usually with adjustments for cut-off frequencies and a choice of filter slope.  Sometimes an electronic crossover can also add gain to the signal.  Raul and I were talking about using an electronic crossover only for a low pass filter to the subwoofer.  The frequencies above low bass would go direct to the main amplifier, but at the input of the main amplifier, all you need to do is to add a single capacitor in series with the signal.  That capacitor in conjunction with the input impedance of the amplifier will act as a passive high pass filter with a gentle slope of 6db/octave.  For that, you would like to have a preamplifier with two pairs of output jacks, but it's not really mandatory; you can derive a second output between the main amp and the electronic crossover you use to provide the low pass filter to the subwoof.  I like this second option because the high pass signal does not have to go through a second circuit.  Trade-off is something called "insertion loss"; you lose a little gain in a passive filter, usually inconsequential.