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

[whoaru99]

The only time one way is implicitly preferred over the other is if that way has high pass output and you want to use it (or the more obvious, you don't have workable line level outputs). Otherwise, I suggest using whichever way is more convenient for the wiring.

At speaker level typically facilitates more connection options. Parallel off at the amp terminals where the speakers are connected, use B speaker if A+B are parallel (which most are, but not all), can even parallel off right from the speaker terminals to the sub.

 

[JoeESP9]

All of their subs have a single Speakon high level input. They don't state whether it's a dual or single.

 

[Grenadeslio]

not all subs strip out the lows from the mains,

you're absolutely right, very few good subs do actually. You see this more often with Bass units included with surround systems that come with tiny satellite speakers like Bose Acoustimass etc, these are usually not true subwoofers.

then there are the very few high end subs that have variable high pass, these are few and far between tho.

 

[Steve88]

The sub company that recommends connecting the inputs of the sub from the amp is REL, which I happen to own. It is the smartest way to hook up a sub. Other methods take away bass from the mains and redirect it to the sub, how stupid is that? RELs allow the mains to run full bandwidth, and use its sub to fill in the bottom, where many speakers can't reach. This method is a win-win scenario.

I'm not sure why you feel directing bass away from the main speakers is stupid. If the main speakers don't have much below 50 hz, why should I push them to try and reproduce it when the sub is much more capable?

 

[CraigVMN]

I'm fortunate in that my stereo rig incorporates a Parasound power amp that has a pair of looped outputs that I use to run RCA cables to my sub. Interesting note - I used a Y cable to combine the L/R output to a single cable to the sub's LFE input, but doing so caused the output to the main speakers to be in mono.

 

[hopeless]

Interesting discussion. I do whatever works in the situation. My first choice is to high pass my mains, especially with a smaller amplifier. I'm all bookshelves all the time, but rarely use a sub. Haven't had the real estate to devote to one in a permanent situation for 10 years.

 

[whoaru99]

Interesting note - I used a Y cable to combine the L/R output to a single cable to the sub's LFE input, but doing so caused the output to the main speakers to be in mono.

Was that unexpected, considering you shorted the two signal paths together?

Why not wye?

 

[Grenadeslio]

I'm fortunate in that my stereo rig incorporates a Parasound power amp that has a pair of looped outputs that I use to run RCA cables to my sub. Interesting note - I used a Y cable to combine the L/R output to a single cable to the sub's LFE input, but doing so caused the output to the main speakers to be in mono.

I believe that bypasses the subs low pass filter, not a good idea anyway unless connecting an AVR with the appropriate LFE output.

 

[The Fuxtor]

I've heard a few highly regarded members say the high level inputs are preferred but personally I always use the low level RCA connection.Seemd to have much more range in volume

 

[whoaru99]

I believe that bypasses the subs low pass filter, not a good idea anyway unless connecting an AVR with the appropriate LFE output.

Yeah, going into the "LFE" input may bypass the internal low pass, or it may not. Sometimes they label one input that way simply to stave off a bunch of questions, "Should I hook the LFE connection to the Left or Right input?"

Have to check the manual to know for sure.

 

[WaynerN]

I'm not sure why you feel directing bass away from the main speakers is stupid. If the main speakers don't have much below 50 hz, why should I push them to try and reproduce it when the sub is much more capable?

Do you think the cross-over point is a brick wall? It has a slope, so it not only knocks down the 50hz stuff, it goes up and beyond. A 12db per octave slope is more then likely used.

 

[CraigVMN]

Was that unexpected, considering you shorted the two signal paths together?

Why not wye?

Yes, it was, as they were outputs.

I believe that bypasses the subs low pass filter, not a good idea anyway unless connecting an AVR with the appropriate LFE output.

I now have a pair of RCA's going to two inputs, and there is a switch on the sub to engage its variable crossover or not.

 

[rothwellaudio]

Do you think the cross-over point is a brick wall? It has a slope, so it not only knocks down the 50hz stuff, it goes up and beyond. A 12db per octave slope is more then likely used.

No, it's never a brick wall, but high pass filtering the main speakers isn't a bad idea. Relieving them of bass duties reduces the cone excursion and reduces distortion and can make the mid-range a lot clearer.
The counter-argument is that crossing over the sub to the mains at a higher frequency runs the risk of the two not integrating well and there being an audible discontinuity.
Both arguments have merit.

 

[WaynerN]

In your example (not saying its wrong), almost every speaker made has faults in its low end, with the exception of some exotica stuff. However, I think the mids (if present) and the tweeters are made to match the woofers of most speaker systems, so relieving the pain of over-stressing on one driver (in this case, the bass), doesn't mean the other drivers are not afflicted by being over driven.

My opinion is that a sub should enhance the mains, not replace them or any part of them. It makes the blend much better by letting each do its job that is was designed for. Lets face it, the sub is basically a one octave wonder in most cases, maybe 1 1/2 octaves. That is down where most people can't even tell what note its playing due to the ears lack of sensitivity to notes at that low of a frequency.

 

[rothwellaudio]

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.

 

[Grenadeslio]

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 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.

The Canton Plus C passive matched with the Plus S I believe crosses at 120hz, very schveet setup. These were not cheap when new, especially in the real wood veneer. The Plus S have surprising bass output and are pretty good on their own but they really shine as the system.



They also made a powered version the Plus B shown above.

But with my Modulus System I prefer running full range with the matching sub even though it has an adjustable high pass Xover through selectable dip switch settings on the rear of the external control unit.

 

[opnly bafld]

@Grenadeslio

Any examples that are not 30 years old?

 

[whoaru99]

Yes, it was, as they were outputs.

I suppose you know now, but the general rule of thumb is it's permissible to split outputs using "Y" but not to combine them using "Y".

 

[rothwellaudio]

The Canton Plus C passive matched with the Plus S I believe crosses at 120hz, very schveet setup. These were not cheap when new, especially in the real wood veneer. The Plus S have surprising bass output and are pretty good on their own but they really shine as the system.

Yes, that's exactly the type of setup I had in mind. Another example (among many) would be the Realistic Minimus 7. On their own they're "full range", though they don't do proper low bass and many people might want to augment them with a sub. It would be possible to have the sub just add the missing bass without filtering the mains, but an alternative would be to high pass filter the mains and have the sub fill in what's been taken off the mains as well as adding the low bass. That would relieve the small woofer in the Minimus 7's of a lot of stress and allow them to play cleaner and louder. The difficulty is getting the sub and mains to integrate seamlessly.
Anyway, I'm not saying either way is the right way to do it - just that both options are possible and neither is stupid.

 

[rothwellaudio]

Purely by coincidence I've just seen this page about a DIY small speaker similar to the Minimus 7
http://www.zaphaudio.com/ZBM4.html
Here's a quote from the author about using a sub with them:

If run full range, all it takes is about 10 watts to drive the woofer into distortion at 70 to 80hz. These speakers actually sound pretty good when run full range, with low end distortion that's not nearly as bad as 3" woofers. Just don't have any unreasonable expectations about their output capability and bass cleanliness when not actively crossed over to a sub.

Now if you do need more output, you will need a subwoofer and the two LR4 power handling charts should help you select an initial crossover frequency. After that, let your ears do the tweaking. If low bass content seems to cause mid bass grunge from the minispeakers, your sub crossover frequency is likely too low for your preferred listening level.

I have to say, using these with a good sub and an active sub crossover sure does clean up the midrange quality a bit. Sure, the low end sounds ok all by itself, but expect to be blown away when you compare that to what you might get with a Dayton RS subwoofer for example.