Strategies for 2.1 (or 2.2) Crossover Management options without an AVR

[KEW]

Most stereo preamps, integrated amps, and receivers only provide a full range output (if that). While most subs have the crossover control, the problem is you are still forced to run your main speakers full range. In my experience, relieving the mains of the lowest frequencies makes an audible improvement in sound quality; I believe pushing the drivers to xMax compromises its ability to maintain fine control over other more nuanced content. And, of course, you are also reducing the load on the amp by crossing above the speakers natural roll-off.

Of course an AVR is an obvious solution, but the question is what is available for someone looking for stereo only using subwoofers who is wanting to control the crossover of the speakers?

What options are out there?

 

[Steve81]

The cleanest solution eschewing a standard AVR is buying a stereo receiver or preamp that features bass management. Options that come to mind there are the Outlaw stereo receiver, and preamps from Emotiva and Parasound.

Beyond that, some subwoofers feature built in high-pass filters that can be used by routing a preamp out to the sub, and then the filtered outputs on the sub to an amp or the "main in" on a stereo receiver (if it has one). The SVS Ultra-13 comes to mind as being one of the better options in this regard since you can adjust the high/low pass frequency and the XO slope to best match your speakers. Of course, this may be somewhat messy in terms of cabling.

 

[shadyJ]

There are outboard crossovers you can get, a bunch from Behringer among other manufacturers, like this one. MiniDSP can also do crossovers. If you want something simpler, Hsu has a couple of outboard high pass filters, this one and this one.

 

[XEagleDriver]

Agree with KEW's premise, keeping the low bass signal away from bookshelves is beneficial.
I am using Steve81's suggested option #2 (sub's speaker level inputs through the sub's high-pass filter, then sub's speaker level output to the bookshelf speakers) and this works very well.
- I did not find cabling an issue of significance (only one more set than a conventional install).

Cheers,
XEagleDriver

 

[ski2xblack]

miniDSP, digital crossovers of the pro-audio variety are a great suggestion, but they require pre-out/main in loop or separates.
Ghetto, but better than nothing would be line level analog high pass filters, which also require pre-out/main in loop or separates. I used one of those f-mod line level filters for this, but it was only a 6db/oct slope and didn't offer as much protection for the drivers as a steeper slope active would provide.

It's too bad HK stopped making the HK990. That was a two channel receiver with all the requisite bells and whistles.

What I don't understand is why all these fancy digital headphone DAC/preamps don't offer bass management, like the Oppo pre.

I still like the Marantz slim line avrs for stereo too. Bass management, and pre-outs for the L/R if more power is needed.

 

[KEW]

There are lots of ways to skin a cat, and I thought it would be good to get different strategies all in one thread (as well as a good learning experience-for example, I was not aware of the XO's on the Parasound gear).

I am using a Emotiva XDA-2, Gen2 as a pre. It has XLR and RCA outputs which both stay active. The XLR run to a Yamaha P7000S pro amp which has an analog High Pass Filter and from the amp to the speakers. The RCA outputs run to my subwoofers (which have XO control).

Right now, I am running the subs in stereo (not combining the signal). The subs are located close to the respective L&R speakers. Should I combine them or leave as is?

Also, I gather that the Crown XLS amps use a digital crossover. Were someone to copy my setup with a Crown (such as the XLS-1500), would there be a time delay for the mains for the A to D, processing, and back to A conversions to take place? Would it be a cause for concern?

 

[KenM10759]

My SVS SB1000 also has speaker line inputs (or whatever you Audioholics call them) and they pass the signal through a filter to send low frequencies to the sub and the rest back out to the other speakers.

 

[PENG]

I am using the Rythmik's filtered (80 Hz) output. The $500 Denon AVR-X3100W as preamp is probably a reasonably priced and much more flexible solution.

 

[KEW]

My SVS SB1000 also has speaker line inputs (or whatever you Audioholics call them) and they pass the signal through a filter to send low frequencies to the sub and the rest back out to the other speakers.

This works, but does not address the objective of relieving the amp and speakers from playing the low frequencies. The SB1000 sends a full range signal to the speakers (no high pass filter applied).

 

[KEW]

I am using the Rythmik's filtered (80 Hz) output. The $500 Denon AVR-X4100W as preamp is probably a reasonably priced and much more flexible solution.

You must have something custom on your Rythmik. Mine does not have any outputs!

 

[PENG]

This works, but does not address the objective of relieving the amp and speakers from playing the low frequencies. The SB1000 sends a full range signal to the speakers (no high pass filter applied).

It sort of does, except the HP is fixed at 80 Hz 12 dB/Octave, same as the one in my E15HP. The line level RCA outputs are connected to the main speaker amplifier not the speakers. Some SVS subs, such as the original PCU has both line level (RCA) and speaker level outputs that I think you are referring to.

From the manual:

"These outputs are used in 2-channel applications to high pass the signal being sent to the loudspeaker amplifier. The line level outputs feature a fixed 80 Hz 12 dB/octave high pass filter."

 

[PENG]

You must have something custom on your Rythmik. Mine does not have any outputs!

Yes, I paid extra for them.

 

[ski2xblack]

Right now, I am running the subs in stereo (not combining the signal). The subs are located close to the respective L&R speakers. Should I combine them or leave as is?

I think that would depend on the modal response you're getting with them in their current placement vs. what other placement would result in. The best place for smooth bass over a larger area rarely coincides with the placement of the mains, as I'm sure you're aware. The only way to find out for certain would be a sub crawl or some REW duty to empirically test other placement options. Stereo shouldn't matter at what are essentially omnidirectional frequencies, I wouldn't imagine, unless the subs to reach up into frequencies where they could present directional cues (high crossover freq, shallow slopes).

 

[KEW]

It sort of does, except the HP is fixed at 80 Hz 12 dB/Octave, same as the one in my E15HP. The line level RCA outputs are connected to the main speaker amplifier not the speakers. Some SVS subs, such as the original PCU has both line level (RCA) and speaker level outputs that I think you are referring to.

From the manual:

"These outputs are used in 2-channel applications to high pass the signal being sent to the loudspeaker amplifier. The line level outputs feature a fixed 80 Hz 12 dB/octave high pass filter."

I focused on Ken saying he used speaker line inputs and assumed that he is using the speaker level inputs. In teh section on connecting the sub using the speaker level inputs, it says:

Adjust the low pass filter to blend with the natural roll-off frequency of your loudspeakers

So I suspect there is no high pass filter.

Ken, if you can, use the line level inputs and outputs to take advantage of teh built in HPF. This will require separate amplification or a "main-in" connection on your current receiver (which is pretty rare). It will be fine without it, but a little better if you can do it this way.

 

[KEW]

I think that would depend on the modal response you're getting with them in their current placement vs. what other placement would result in. The best place for smooth bass over a larger area rarely coincides with the placement of the mains, as I'm sure you're aware. The only way to find out for certain would be a sub crawl or some REW duty to empirically test other placement options. Stereo shouldn't matter at what are essentially omnidirectional frequencies, I wouldn't imagine, unless the subs to reach up into frequencies where they could present directional cues (high crossover freq, shallow slopes).

So if I follow, there is nothing to be gained by running them stereo and the potential for something to be lost, correct?

 

[PENG]

I focused on Ken saying he used speaker line inputs and assumed that he is using the speaker level inputs. In teh section on connecting the sub using the speaker level inputs, it says:

So I suspect there is no high pass filter.

Ken, if you can, use the line level inputs and outputs to take advantage of teh built in HPF. This will require separate amplification or a "main-in" connection on your current receiver (which is pretty rare). It will be fine without it, but a little better if you can do it this way.

You are right, he did say speaker level. I missed that because of my preconception. My Polk sub has a toggle switch to engage the filter when speaker level outputs are used to connect the main speakers but I suspect those scheme could degrade the SQ though likely not noticeable as such schemes are mostly there for satellite speaker systems.

I am sure you are correct that if Ken is using the speaker level outputs he won't benefit from the HPF and he should use the RCAs instead if possible.

 

[KenM10759]

I'm all set. I run my SB1000 via the LFE output of the Denon AVR-1912 and anytime I want simple 2.1 I just press a button on the remote to select it. The OP (Kurt) is the one asking about other options.

 

[ski2xblack]

So if I follow, there is nothing to be gained by running them stereo and the potential for something to be lost, correct?

I'm not absolutely sure that there is nothing to be gained from stereo subs. I do recall an interesting video over at AVS that featured commentary from an experienced installer, who didn't seem to be the black hat type, having a preference for front located, stereo subs. I think his take was that bass transient information is more important than absolutely smooth response, and he wanted the kick drums to sound (or perhaps feel) like they coincided with the rest of the band. I'm not sure if he was out to lunch or really on to something. And his explanation was a bit more fleshed out than my shoddy recollection of it.

Also, if your mains are weak in the mid-bass, co-located subs can be crossed higher to augment them without directional cues being an issue. Yes, that may compromise bass smoothness, but you would essentially have full range, much harder hitting mains to play with.

The best route to take, since each and every listening room is it's own bag of acoustical quirkiness, is to test it out in situ, assess, tweak, assess, tweak...

 

[PENG]

I'm all set. I run my SB1000 via the LFE output of the Denon AVR-1912 and anytime I want simple 2.1 I just press a button on the remote to select it. The OP (Kurt) is the one asking about other options.

Got it, you were only commenting on the "other options". Like I said in another thread, as weird or even wrong as it may sound, the best option seems to be using a multichannel AVR, even for a strictly two channel system. That's because there are no two channel receiver that comes with highly adjustable crossover points, Sub EQ, dynamic EQ etc. The Outlaw mentioned has some capability but not enough imo. Minidsp products would work but don't seem cost effective, compared to the $500 X3100W or the $800 X4100W that comes with XT32 and Sub EQ HT.

 

[ski2xblack]

One dedicated two channel integrated that I almost forgot about, but that has bass management and PEQ, is the NAD C390DD. It's a pretty modern, fancy pants integrated with everything a 2+subs person would need, but is a poor value proposition at near flagship AVR pricing (probably why I almost forgot about it).