@lewm
So, with the Velodyne Digital Drive subwoofer, the entire line goes through the subwoofer from the pre-amplifier? And the Velodyne has both a high pass and low pass filter, which the high pass filter line then goes to an output line into the amplifier, and the low pass filter signal is delivered to the subwoofer? Or, would I still have a direct line from the pre-amplifier to the amplifier that goes through a high pass filter, which would either be analog, or, if digital, need an ADC and DAC?
(And the amplifiers are the Ypsilon Hyperion (input impedance 22k Ohm). I previously had Atma-Sphere MA-2, which were also very good.)
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@lewm
Thanks for the clarification. My favorite pieces involve the cello or cello and piano. (Yes, Bach, but also Beethoven and Brahms.) Consequently, I was thinking that the crossover should be below the lowest cello note, which is 44 Hz, as I wouldn't want the cello to sound like it's jumping around.
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Unfortunately, the more I read about HPF, the less inclined I am to use them: everything that I’ve read so far indicates that their use does impact SQ.
Additionally, here’s a paragraph about higher order HPF influencing signal moreso than lower order HPF (but it is just the internet, which could be wrong):
Although there is no limit to the order of a filter that can be formed, as the order of the filter increases so to does its size. Also, its accuracy declines, that is the difference between the actual stop band response and the theoretical stop band response also increases.
Learning about subwoofers is an exercise! I’m not sure whether I should proceed in this direction, given the components in my system. . . although, it would be interesting to compare any differences in SQ with a properly installed digital HPF with subwoofer, which replaces my pre-amplifier / amp / ESL system currently. But that might be a project for another time. . .
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@rsf507
Yes, to a casual observer, you may wonder why we are talking about subwoofers on a thread that started with phono stages. Well, the phono stage question was resolved rather quickly and emphatically in the first few pages of the thread, with a brief foray into amplifiers. However, three of the five of the regular contributors to this thread all have the same ESL speakers, so that’s probably the main reason I thought it was best to continue any detailed discussion about my sound system on this thread, as opposed to starting another one in the speakers section. Additionally, there are many other factors that one can consider: I think that individuals that listen to vinyl have a sound in common that they appreciate; additionally, at the level of system we’re talking about, I would probably have to sort through a hundred posts about average equipment; whereas, here, most realize that we are discussing very high end equipment.
Thanks.
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@rauliruegas
Yes, you would be correct that I have no experience with subwoofers. Does the Velodyne insert into the system between the pre amplifier and amplifier, with both a LPF for it's own amplifier and an internal HPF that then is sent to the monoblock amplifiers?
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@rauliruegas @lewm
Which Velodyne subwoofers would you recommend for best match and highest quality? What about Martin Logan subwoofers, or other brands? (Velodyne has no photos of the back of their subwoofers and no diagram of connections on their website or downloads; the only Velodyne video on YouTube is 20 years old. It seems like they're trying to hide something!)
Thanks.
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@holmz
I was just reading multiple reviews about various HPF and they all say that there is a noticeable affect on SQ. But I suppose it's worth a trial. The current problem is finding the best ones to initiate this trial with:. Vandersteen, Martin Logan, or Velodyne? (I suppose Magico would be an option if it weren't a trial, but a definite move.)
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Correction: I finally found a diagram of the back of the Velodyne subwoofers under quick start guide on their website. . But it’s a very poor diagram, and doesn’t explain anything about the HPF, LPF, etc. It looks like their target is the home theater crowd. Martin Logan website is more informative, actually has good diagrams, and mentions the difficulty of incorporating subwoofers with ESL, but they only appear to have LPF, which would need an external HPF, etc, which gets into the issue of SQ.
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@mijostyn
Understanding that digital LPF is better for sub woofers, can a high grade analog capacitor (e.g. silver Duelund CAST) be used for the HPF to the ESL with good results? What’s the main disadvantage to using an analog HPF via an in line capacitor and a digital LPF to a subwoofer?
What are the higher end passive sub woofers on the market? (I do have an extra couple of amplifiers (class A and AB) sitting around).
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@lewm
because of the quality components of the pre- and amp, I am leaning towards an capacitor HPF, as opposed to running it through the sub, which just has a standard 6db per octave HPF, which would just be a standard, probably low-grade capacitor, correct? A silver Duelund CAST capacitor in line with the two components, and then a separate line to the subs: it seems that Martin Logan subs might fit in the system better, since they also make ESL, and are more designed for a two channel system. It seems that the Velodyne is for multi-channel home theatre use.
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@holmz
My pre-amplifier has two outputs: RCA and XLR, so I can run the RCA to the amplifier and the XLR to the subwoofer, or vice-versa, as the amplifier has both RCA and XLR inputs. I was leaning towards a lower crossover for the HPF, somthing like 80 Hz, or maybe 60-80 Hz, to keep the midrange in the ESL’s. The input impedance of the Ypsilon Hyperion is 22 kOhm, and I was looking at a silver capacitor to make the HPF happen, although, I’ve got much to learn about the science and the curves.
I figure I could use a digital LPF crossover for the subwoofers, since the signal to the bass might not be so noticeably affected by the change.
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Hmmm. . .I’m back to the consideration stage: apparently, the most neutral approach to add a HPF in my current system is via a high-grade capacitor. However, these capacitors only give a 6 db / octave adjustment, which means starting at 80 Hz (so that the mid-range isn’t affected), would only drop the volume by 6 db at 40 Hz, which is the lowest sound played by the cello, although the piano may drop to 30 Hz on occasion, which would give about a 9 db decrease in signal to the main ESL speakers.
To put things in perspective, one click on the volume knob on my pre-amplifier is about 2 db (and it is usually set around 26 clicks) so we’re talking dropping the volume only 3 clicks for most low frequencies, and at most 4 clicks for the lowest, which is only going to be about a 10-20% drop in volume for these frequencies. So I’m not sure a standard analog capacitor HPF is going to make much of a difference in attenuating the signal to the main ESL’s; and apparently, the built in HPF in subwoofers are also the standard 6db / octave. Ideally, I would get a high quality analog HPF, which would minimally affect the SQ, and filter at 24 db / octave. . .but that may be like the tooth fairy: impossible!
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I've read some comments on a subwoofer thread about how the user preferred Class A/AB amplifier for the subwoofers, as the class D truncated notes too quickly, and the like. Consquently, currently, I'm leaning towrards favoring passive subwoofers driven by a Class A or AB amplifier(s) (which I already have). I think I'll give Duke a call at Audiokinesis sometime soon to see what he has to offer, as I think the "swarm" can be purchased with only passive subwoofers. . . but I'll still have address LPF, HPF, etc. with that option.
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@mijostyn
I spoke with Duke LeJeune at Audiokinesis, and he agreed with you that the "Swarm" would not suffice in my room, due to its size. He mentioned that he could make some custom subwoofers with either 12" drivers or possibly with s 10" drivers per box. His set up would have the potential to be sealed, vented, or double vented. He also mentioned that his subwoofers are passive, but he recommends a amplifier that can be set to a 4th or 5th order LPF. Presently, I'm going to investigate and pursue this option for the next few weeks.
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@rauliruegas
Thanks for your suggestions. I'm going to see what Duke at Audiokinesis comes up with. He sounds like he really knows what he's talking about, and is interested in helping me get the best out of my Sound Lab ESL's. He's also a Sound Lab dealer, so he's very familiar with what the speakers could use for augmentation. It sounds like I'm probably headed down the custom-built subwoofer route. Presently, we're looking for an amplifier / HPF combination that can work down to 16 Hz, which is low C. (Yes, that is a key note in Bach's Passacaglia and fugue in c minor.)
Presently, most every other component in my system is non-negotiable.
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@lewm
The standard amplifier that he pairs with his subwoofers goes down to 18 Hz. We'll see what he's able to find. (By the way, if you haven't heard that organ piece, you should give it a listen. My friends who don't even like classical music are amazed by that composition.)
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@lewm
Yes, that makes sense. I'll see how things work out. Presently, with just the SL speakers, and playing the 16 Hz note on vinyl, the walls shake; oddly, playing the same piece on digital doesn't cause much to shake, but just the normal vibration of the listening chair, etc.
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