One sub, a two channel system ,one HT reciever ??


I have a nice two channel system that uses the Pre Out's of a HT reciever to a line input of my preamp to integrate the HT system with my two channel gear.

Right now, the sub is driven by the LFE of the HT reciever and bypasses the sub's crossover and it works well.

To use the sub with my two channel gear... it would appear that I take the power amp out put to the speaker inputs and then the speaker out's to the speakers and set the sub crossover where I want.

However, the manual says use either the line level input OR the speaker level inputs but not both.

a) what happens if I screw up and fail to unplug them appropriately

b) Is there a clever way to hook up the sub with my two channel system and the HT system?
tcatman
It is reasonably simple. When you use the line level in and out you are using the crossover and rolling your main speakers off at the subs crossover point. When you use the speaker outputs you are NOT rolling off the main speakers. In theory the first has the advantage of lessening the load on the main speakers because they no longer have to reproduce low bass. Nevertheless, I find the second method to work much better. I currently have three types of subs [REL, Nelson Reed , and HSU] and have had others in the past. The critical factor is not having to run your signal through the crossover. I have yet to see a crossover that did not degrade the sound. I am assuming that in the first case you are running the pre out to the sub input and the sub output to the power amp in and thus using the subs crossover. Since you did not name your equipment I can't be more specific. If this is not true advise me and I will post further. When hooking up equipment I have always found it helpful to visualize your system as a stream with your signal source at its head. Just follow the stream toward your speakers, hooking it up as you go.
When you use the line level in and out you are using the crossover and rolling your main speakers off at the subs crossover point.

On some equipment this can be a limitation yes. However, I think there are preamps out there that allow you to have control over each speaker individually so the sub can be crossed over or not and the speakers can be crossed over of not.

I'd look into the Anthem D1 or D2 if you want a high quality HT preamp with plenty of flexibility and that could also serve as a source for a decent two channel system or a two channel + sub system.
If your receiver folds the LFE channel into the mains when set to (large mains-no sub)....you can simply add something like the Paradigm X-30 crossover (around $100 used)into the system. (or any other good crossover on the market).

It would connect like this:

Two channel preamp>>Paradigm X-30>>Mains and sub. This sends the fullrange signal from the receiver, to the preamp. The preamp feeds it to the Paradigm crossover. The paradigm crossover filters the mains and subwoofer, or...just the subwoofer if you want to run the mains fullrange. (a second set of preamp outs required or splitter cable for this method).

I don't agree 100% with "Stanwal" on his second choice option being better....but don't really dis-agree 100% either.

Running the mains fullrange, is speaker dependent (the main speakers). The speaker level connection method assumes that the mains have a smooth low freq's response....many small ported designs are anything but. So....this method depends.

I also don't agree with this:

"The critical factor is not having to run your signal through the crossover".

If this were true (critical), we would all be using single driver speaker systems. Sometimes the gains, more than make up for any loss.

Note: My options also depend on a few things.

Dave
My equipment is Kef 104 /2's (with a Kef Kube external line level cross over currently not being used)
Audio Research LS 15
Classe Ca 2200 Power amp.
Yamaha 650 HT reciever.
Velodyne DLS-3750R sub
Levinson transport and Sonic Fronteirs DAC

The Velodyne sub has a variable cross over. Which is now set to off because the HT Reciver is managing the cross over point for HT material.

The reciever has a lfe output which I am using now for HT.

In two channel mode... I just switch inputs on the LS15 and leave the HT equpment off.

So, from what I understand I could do this.

I set the yamaha to large mains and No sub.
Ditch the LFE output to LFE line level input.
connect the sub by going from the power amp to the speaker input left and right of the sub and then from the speaker outputs to the KEF 104's. Then set the cross over on the sub to 120 Hz. Then run the reciever's auto calibration with the main LR channel set to 12 oclock on the volume control. This calibrates all of the surround and .1 channels.

This way I get the benfit of using the sub for music with the bass limited kef's and keep the LFE info from HT material going to the sub as well using the yamaha's processor.

Am I off base here?
Thanks for the reply's
I'm a huge fan of using bass management to integrate a subwoofer. All three of the active crossovers I've used have only had a positive impact.

For your particular situation the NHT X2 filter will solve your problem. It accepts both an LFE input and Left & Right line level inputs.
The idea behind not running the signal through a crossover is that it represents an additional degradation of the signal before it has been amplified, a degradation here can never be recovered. The crossover inside speakers represent a division of frequencies of an ALREADY AMPLIFIED signal and has far less effect on the sound. I am unfamiliar with multichannel systems and so don't understand the purpose of setting the crossover at 120hz but in operation no sub should EVER be set this high. Anything operating in that range is not a sub but a woofer. I run my subs as low as possible, I never have the sub crossover set above 40hz. In this way the output of the sub is nondirectional and it supplements the bass of the main speakers instead of interfering with it. Again I am writing from the perspective of 2 channel sound and of someone who uses subs with response below 20hz. The Nelson Reed was specified to do 120db at 20hz and extend to 16hz. The REL and HSU will go almost as low but not nearly as loud; they don't have 8 12" Volt drivers as the Nelson Reed.
With every system component there is a risk/gain ratio to consider. Stanwal is correct that every additonal piece of electronics (passive or active) degrades the signal. Whether this degradation is audible is the key. My stance is that the decrease in distortion produced by the main speakers with the bass load removed far outweighs the distortion added by an active crossover.

If your main speakers are true full range (many floorstanding speakers are not even close), then running the main speakers full range can work. Otherwise, high passing the main speakers will yield greater clarity.
I am currently running Spendor SP-1/2s with a REL stadium 11 sub. I am using the speaker level inputs to the sub rather than the line level which would allow me to roll off the bass. Why. First, this is what REL recommends. Second , I have never had an active crossover I couldn't hear. Such may exist but they would be very expensive. A custom passive crossover would be the way I would go if I was inclined to use one. For me the critical factor it that running the main speakers full range is what they were designed for. Rolling off their bass may enable them to play louder but when I have tried it I found the benefits mostly theoretical and the drawbacks obvious. BUT, if I have learned anything in 45 wears in audio it is we all hear differently and listen to different things in music so it a personal choice.
Tcatman,

I agree with Shadorne's suggestion re high quality HT pre amp. Even my vintage Proceed PAV/PDSD pre/pro combination does a fine job managing the interface of my KEF 104/2s and Velodyne HGS-15, whether stereo or 5.1. I take the balanced LFE output from the PDSD to a Velodyne SMS-1 room-correction manager, then to the balanced input of the HGS-15. Crossover is set at the pre/pro to 80 Hz, the Velodyne crossover is switched out, and the speakers are set to small. I can adjust the level of any speaker with the PAV/PDSD remote, and I set them with a RS SPL meter using the white noise generated by the PAV.

I've tried variations of this setup, but this is the one I prefer. Experienced listeners tell me they are unaware of the sub as a separate source of sound.

db
Running the mains full range as Rel suggests, either works, or doesn't work...it has a lot to do with whats going on with the main speakers. The Kef's may work great...many smaller ported speakers may not, again....it depends.

No amount of gibberish by Rel, or anyone else, can change the facts.

If it works...thats great. If it doesn't work (and it won't always work)....you will need to fix it, or you won't be happy.

Dave
Running the mains full range as Rel suggests, either works, or doesn't work...it has a lot to do with whats going on with the main speakers. The Kef's may work great...many smaller ported speakers may not, again....it depends.

Well said. I could not agree more.

FWIW: The safest approach is to NOT run the speakers full range. Although the best possible approach may be to run the main speakers full range with the sub just filling the bottom octave - this option is however restriced to equipment that is designed to work together and with mains that have woofers as big as a subwoofer to begin with. The same manufacturer and same design philosophy in the bass is required, IMHO - otherwise there is a fair risk of a "dog's breakfast" when just randomly pairing up gear...
For me the critical factor it that running the main speakers full range is what they were designed for.

True, *if* they were really designed for it. Many (probably most) are not; otherwise we'd see many 4-way designs with at least 12" woofers. And that's effectively what is created by high-passing a 3-way speaker system and letting a subwoofer handle the bass.

Bass is tough and reproducing it creates large amounts of distortion.

Rolling off their bass may enable them to play louder but when I have tried it I found the benefits mostly theoretical and the drawbacks obvious.

Removing the bass from a driver that can't effectively handle it reduces the overall distortion of the speaker system allowing it to not only play louder, but cleaner.

It's possible that some people don't care for the less distorted sound.
It seems to me that my biwired KEF 104/2s are just a bit more transparent when the crossover is set to 80 Hz. They also sound fine full range without the sub, but the low pedal notes of a pipe organ, for example, are missing. The HGS-15 fills that in, and can provide that subtle more felt than heard experience when a big pipe is invoked. For HT, you really need the sub; for jazz and chamber music, my favorites, maybe not.

db
Rolling off their bass may enable them to play louder but when I have tried it I found the benefits mostly theoretical and the drawbacks obvious.

One of the obvious problems from removing copious amount of bass distortion is that you can now hear copious amounts of lower midrange distortion or you may hear the obvious dull compression of the midrange. Often these effects are hidden by bass distortion. Masking effects on the ear do work in a designers favor...a ported resonant and harmonically distorted bass with a lousy impulse response can hide a lot of other shortcomings. This is not well understood but as a consequence modest amounts of distortion are often regarded as pleasing - making the music flow and sound more natural by hiding the obvious midrange blemishes of a poor design. This may be one of the reasons it is so hard to match a subwoofer to a panel...since a good panel has very low midrange distortion it sounds worse when masked by the subwoofer (contrary to a normal speaker that benefits from added bass distortion: think your average car stereo which sounds pretty good despite all the distortion)
Bob , without getting personal I would like to ask if you have ever heard ANY of the equipment I have described. I am describing experience, you are mouthing platitudes The Spendor , for example , was designed by the BBC and used around the world by other national radio networks as monitor speakers. The Nelson Reeds were designed as monitor speakers for movie studios. I probably made a mistake posting on an AV Question as the performance parameters appear to quite different. I was a Quad dealer for over 20 years and of course they are famous for distorted sound. Note to self, no more AV postings.
I was a Quad dealer for over 20 years and of course they are famous for distorted sound.

Do I detect some tongue-in cheek?

I would add that anyone with a typical modern system where it is often difficult to hear dialogue on movies without jacking the sound way up (background sounds cloud diaglogue) needs to ask themselves what might be wrong with their midrange and what might be wrong with the "impressive" bass....one word "distortion".
Stanwal,
without getting personal I would like to ask if you have ever heard ANY of the equipment I have described. I am describing experience, you are mouthing platitudes

No, I've not heard any of the equipment you mention and I don't doubt your experiences at all. I didn't mean to imply that I did. My platitudes are based on reason (and a little physics) and my experiences, nothing more.

Sorry to offend.
Thanks all

What worked was to run the Kef 104.2 full range. I used the Kube 200 active equalier to extend the kef 104-2 base range and the second line level output of the Kube to send a second independent line level signal to the Velodyne subwoofer. I set the low pass crossover to about 60 Hz which gives me the missing bottem octave.

More playing to do but I am making progress.

I suspect with a better quality sub that I would have more options since this sub vibrates or buzzes if I set the cross over too high (80 hz).
Tcatman,

My experience with Velodyne is with the HGS 10 & 15 subs, and they are indeed fine. Placing the sub on an Auralex SubDude is a big win.

I have a KUBE for my 104/2s that I have never tried. I've read it introduces distortion, but that may not be true, or an observation based on an incorrect hookup. Anyway, I'm happy with the 80 Hz crossover, freeing the 104/2s from LF duty. I could be happy with just the 104/2s in full range mode, as well. The only setup I don't care for is the 104/2s and the HGS-15 both covering the under 80 Hz range, and that seems similar to the mode you prefer.