Does using high lvl speaker in/out on subs degrade signal to speakers?

rothwellaudio said:
What I had in mind was two-way bookshelf speakers with fairly small drivers. Asking them to reproduce all the bass on a recording is asking a lot. The low bass that they can't reproduce is still moving the voice coil and therefore having an impact on the frequencies they are capable of reproducing. Filtering out some of that bass lightens their workload considerably. Of course, as you point out, the sub would have to be capable of going high enough to take up the slack.
I agree, when using larger, or three way speakers the benefits wouldn't be as great as with the small bookshelf speakers.
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Fair enough. I was referring to floor standers with my comment.

I run an REL sub with my JBL Studios per the REL method of signal from amp with great results. The JBLs woofers are pretty awesome for4.5 inchers, plus I do not push the system that hard (vinyl listening system).
 
knifeswitch said:
I made no assumption. It is what “I’ve read and heard”.
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Sounds like you have heard and read what many of us have also heard and read ...

If you have the option, then listen to it both ways ..

Personally I always use the high level connections ..
For a lot of the reasons that you've already read about, and a preference for very short low level signal cables ..
 
I have tried it both ways. Running the mains full range and using a sub(s) to fill in the bottom and using some type of crossover. What I found out was, removing the low bass from my Maggies made them sound better and play louder. The same applies to the Acoustat Spectra 22's that I'm refurbishing.
 
I think about using the subwoofer similar to how I think about my cars.

If I've got to bring home two dozen bags of cement and some sheets of plywood, I could use the minivan. I'm sure it would work and be fine, although performance would probably be noticeably poorer. Instead, I would use the Ram 2500 which is more than capable of the job.

My speakers (Boston Acoustics VR30) are rated to have response down to 42 hz I beleive. They put out some respectable bass on their own, but my Rhythmik LVX12 is much more capable of playing low frequencies. Why would I not send a majority of that "work" to the speaker with more capability? I set up my high pass filter at around 50 hz, and the sub crossover at 55 or 60 hz for just a touch of overlap.
 
opnly bafld said:
Is your high pass 12 or 24 dBs/oct?
Not really cutting out too much.
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I double checked and the high pass is 12 db/octave. For some reason I thought it was steeper. So no, it seems the current setup isn't cutting very much from the main speakers and I'm basically running them full range after all. Maybe providing a bit of relief in the sub octaves.

I may tweak some more to get closer to what I was trying to accomplish, but I'll probably just leave it be because the sub is integrated pretty well with these settings.

I still think high passing the main speakers is a good approach, although more effective with a much higher crossover point or a steeper slope.
 
knifeswitch said:
I have read and heard that it is somewhat preferable to use the speaker in/out connection method when using a sub in a 2.1 situation. I think I understand the reasoning as well and that the amp doesn’t “see” the sub as a load. But IYO, does it color or degrade in any way the signal reaching the speakers?
Mike
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The sub speaker-level inputs are very high impedance, so they do not color or degrade the signal to the main speakers in any meaningful way. There are plus/minus tradeoffs to both connection types:

Speaker-level:
In 2-channel music, you want the sub to be a seamless extension of the main speakers. Ideally, you don't "hear" the sub, it just sounds like the mains go really deep. The advantage using speaker-level for 2-channel is that the subwoofer is driven by the exact same amp signal as the mains. The argument is that having both the sub and mains use the exact same signal allows the sub to be a more seamless extension of the mains. The degree to which that makes a difference can be debated, and will vary based upon individual equipment used, but that is the advantage of using speaker level.

The disadvantage of speaker-level is that there is marginally more distortion because the sub is seeing distortion from both the preamp and the amp, rather than just the preamp only. The amount of distortion is small, and can be debated, but that is the disadvantage of using speaker-level.

Line-level:
The advantage of line-level is that it has less marginally less distortion because the amp is removed from the signal path.

The disadvantage of line-level is that the sub sees a different signal than the main speakers. For a system with a solid state preamp and a tube amplifier, for example, with preamp connections, the sub will be driven by the solid state preamp signal and the mains will be driven by the tube amp. With speaker-level connections, both the mains and sub would be driven by the exact same tube amp signal.

The Reason There is Debate:
The reason there is debate is because both the coloration of the amp (the advantage of using speaker-level to match mains) and the distortion of the amp (the disadvantage of speaker-level) are generally small, so some tend to completely ignore one or the other to claim one connection type is best. That fact is, there are plusses and minuses to both approaches -- neither the plusses nor minuses can be ignored. The best approach is to test both and use what works best in your system.
 
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Tom Brennan said:
Well, it's certainly less moves running a patch cord. I spent my whole working life trying to save moves, it's a habit.

Regards
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Connect one end the amplifier and the other end to the sub, doesn't matter what kind of cable it is, not understanding how it is any different.
 
opnly bafld said:
Connect one end the amplifier and the other end to the sub, doesn't matter what kind of cable it is, not understanding how it is any different.
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I wonder if we're thinking about the same thing.

If I connect the sub with a patch cord I run two short wires from amp to the speakers and one long patch cord from the amp to the sub. 9 connections and one long run of wire, the patch cord. If I connect the sub at speaker level I have to run two long runs of wire from the amp to the dub and two more long runs of wire back again from the sub to the speakers. 16 connections and 4 long runs of wire.
 
Tom Brennan said:
I wonder if we're thinking about the same thing.

If I connect the sub with a patch cord I run two short wires from amp to the speakers and one long patch cord from the amp to the sub. 9 connections and one long run of wire, the patch cord. If I connect the sub at speaker level I have to run two long runs of wire from the amp to the dub and two more long runs of wire back again from the sub to the speakers. 16 connections and 4 long runs of wire.
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You could wire the sub in parallel with the mains to make it a bit easier -- two speaker wires from amp to left/right mains, and a second set of speaker wires from amp to sub left/right (high-level in).
 
Rather than the on going debate between using line level and speaker level inputs I say shift focus to
some bass DSP for the room.
The SQ gains between the two is substantive.
 
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