The Stereo Subs Project

[chessman]

Sigh, as I said a few times, the Velodyne SMS-1 was just there to give me a video diplay of the effect of changes made on the Bryston or the JL Audio sub. No changes were made on the SMS-1 and it is no longer connected to anything.

The splitting the signal affects phase comment is interesting. Are you sure? I do not know a lot about this, other than a decay slope does change phase, but I thought only at the crossover point. Since the frequency response at the 40H crossover is flat, I thought the phase at that point was necessarily equal. And if so, why would that adversely affect a second crossover circuit down signal from there in a frequency range nowhere near 40H?

[ehoove]

Originally Posted by chessman

The obligatory "after" pic.

So how does it sound? I will give a fuller report when the cables have burned in, but initially I would say it sounds great.

Remember I was looking for one octave at the bottom, cleaner mid-range, a little more ease at the top end, and a wider sound stage. I definitely have some of that already, but I do not want to declare victory until I am sure it is not mere wishful thinking. So far, Kind of Blue, The Girl in the Other Room, Winelight, and John Barleycorn Must Die all show distinct improvement.

Great choice of music BTW! You might want to get the crossover off the carpet to delete any static energy from the crossover. IMHO Love your rig BTW
Regards,
Jim

[GaryProtein]

Maybe jdandy can chime in here.

The crossover doesn't cause a problem with the Fathom subs and phase.

I just don't want to give an answer that's only half right.

[chessman]

Originally Posted by jdandy

Randy.......Congratulations on a successful installation. I am glad your final judgment for gain was trusting your ears and not the graph. You may find yourself tweaking the gain one way or the other for the next few days as you listen to assorted recordings, but you will eventually find that one setting that works the best for the majority of your source content. Looking at your Bryston 10B Sub active crossover make me miss mine. It is a fine crossover. Happy listening.

Dan, as usual your observation is spot on. After 10 hours of use I can already hear the new additions starting to settle in. I have a feeling that after a little congestion clears, I will have to reduce the volume on the low pass side. I had unplugged three power cords and turned off the Shunyata Hydra 6 that everything else was plugged into, I added a new power cord to the mix (Bryston OEM), added almost new IC's from preamp to Bryston, and added new IC's from Bryston to subs, so there is a lot of settling in to do.

[Wasatch]

Originally Posted by jfray

I thought the same until I added a G1 to my system. If the sub is integrated properly you will not look back........

Maybe. I have Jim Smith's book and he sez 2 subs for a 2-channel rig.

[Wasatch]

Originally Posted by ehoove

Great choice of music BTW! You might want to get the crossover off the carpet to delete any static energy from the crossover. IMHO Love your rig BTW
Regards,
Jim

Yeah, I have my Elgar on a 6x6 piece of granite.

[jdandy]

Randy.......Yes, there will be some break-in time associated with the new interconnects, although not more than about 50 hours tops.

With respect to phase shifts at the crossover points, this is an excerpt from the 6moons review of the Bryston 10B Sub active crossover:

One thing not immediately obvious is that while the 10B gives you the ability to dial in filter slopes (the degree at which the signal is attenuated below the filter frequency as expressed in decibels of attenuation per octave), it also alters signal phase at that frequency. This isn't so much a feature as it is a natural byproduct of altered slopes. The 6dB position shifts the signal at the filter frequency by 90º, the 12dB by 180º and the 18dB by 270º. This should be considered when selecting the phase setting at the sub. As I found out, it can be extremely useful in blending the sub/s with the speakers. Don't forget that the same changes happen at the high-pass frequencies for the main speakers too. But it must also be understood that the phase changes are effective only at the crossover points, not over the entire speaker bandwidth. A 180º shift will not necessitate the reversing of the speaker leads. These small phase changes can result in a much-improved blend between sub and speakers and a little experimentation is strongly advised.

These phase shifts are only at the crossover points, and only in the drop off slopes, so they do not impact the signals you are sending to your speakers. These are the frequencies you intend to roll off anyway. Nothing to be worried about.

[doggiehowser]

http://thielaudio.com/THIEL_Site05/P..._TechPaper.pdf

This white paper covers some of that discussion of integrating the subwoofer with main speakers. It's a bit technical though.

This review covers an interview with the late Jim Thiel which is a bit more layman in comparison
Thiel SmartSub SS1 subwoofer | Stereophile.com

"Take a speaker like, let's say, a CS1.6," said Thiel—"a two-way speaker with a pretty good crossover. Even a relatively unsophisticated observer would probably hesitate to remove that crossover and use it in a completely different loudspeaker with different drivers, a different-sized enclosure, and so on—and that's the kind of situation that subwoofers are in with processor-based management or the generic crossovers built into the backs of most of them. And, as you know, crossovers are something I have strong opinions about.

"Instead of trying to figure out the filter characteristics you want, I thought we should start with the signal that represents the output you want from the combination of the sub plus the main speaker. To oversimplify, that would be the input signal, and you subtract from it the part that the main speakers will reproduce—you electronically construct an analog of your main speakers that has the same [low-frequency] output characteristics, the same rolloff characteristics, and you take that signal and subtract it from the main input signal. What you are left with, by definition, is whatever the subwoofer will need to put out to blend with the main speakers to produce the desired result. That's the insight that got me excited about the subwoofer project."

Another review
SoundStage! Equipment Review - Thiel Audio SmartSub SS2 Subwoofer and SI 1 Integrator Crossover/Controller (11/2004)

[chessman]

The system is continuing to settle in. Work has prevented as much listening as I would like. Nonetheless, bass has more presence without being louder (the decay seems much more natural), the mid-range is a tad less muddy, and the sound stage is a bit wider.

One surprise to me was that a number of songs that are not bass heavy seemed to be the most affected. A bigger surprise was that the instruments showing more vitality and sparkle were not playing in the bass or even the mid-bass range. They just sound a bit more realistic. I think less bass distortion is yielding less mid-range distortion.

Finally, when one does get into a bass heavy song the stereo subs really shine. Drums have gravitas, standup bass has a weighty strum, and sustained low notes provide a rock solid foundation.

The system sounded great before so this is not an order of magnitude improvement, but it is not subtle either. It is an immediately noticeable improvement, which gets hard to achieve at some point in system building. I can't wait to finish the burn-in and see what else awaits.

[Masterlu]

Originally Posted by chessman

The system is continuing to settle in. Work has prevented as much listening as I would like. Nonetheless, bass has more presence without being louder (the decay seems much more natural), the mid-range is a tad less muddy, and the sound stage is a bit wider.

One surprise to me was that a number of songs that are not bass heavy seemed to be the most affected. A bigger surprise was that the instruments showing more vitality and sparkle were not playing in the bass or even the mid-bass range. They just sound a bit more realistic. I think less bass distortion is yielding less mid-range distortion.

Finally, when one does get into a bass heavy song the stereo subs really shine. Drums have gravitas, standup bass has a weighty strum, and sustained low notes provide a rock solid foundation.

The system sounded great before so this is not an order of magnitude improvement, but it is not subtle either. It is an immediately noticeable improvement, which gets hard to achieve at some point in system building. I can't wait to finish the burn-in and see what else awaits.

Very glad to hear Randy