# REL Stampede... High Level Connection?



## fauzigarib (Mar 11, 2010)

Hi there,

I was just going to get the REW / BFD going for my HT setup.

I had recently tamed my sub's (REL Stampede) response as much as possible (by ear), and was going to go more technical. However, I just wanted to get something clear in my head.

Most REL's connect via both high level (tapping into the outs of the amps to give the sub the same signal as the mains) as well as low level (simple LFE out from the processor).

I would imagine that the BFD is connected b/w the sub and the LFE out on the processor. So you can tame the response all you want, but won't the high-level connection be completely unaffected? As a result, won't your subs response be more or less the same as if you didn't have the BFD in the chain?

-Fauzi


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## Moonfly (Aug 1, 2008)

The high level and low level connection dont work simultaneously, only one works at a time. This is slightly dependant on system setup, but assuming your bass management has your mains set at 80hz then only one connection will ever be active at once.

You are correct in that the BFD goes into the low level connection feed, and as such will only be active when this connection is in use.

Do you fully understand the differences between the high level and low level connections?


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## fauzigarib (Mar 11, 2010)

Moonfly said:


> The high level and low level connection dont work simultaneously, only one works at a time. This is slightly dependant on system setup, but assuming your bass management has your mains set at 80hz then only one connection will ever be active at once.
> 
> You are correct in that the BFD goes into the low level connection feed, and as such will only be active when this connection is in use.
> 
> Do you fully understand the differences between the high level and low level connections?


Moonfly,

I guess I don't. I thought that the High Level stays on all the time and, since it's getting its feed from the amp, it's on or off depending on the frequency you set in the woofer. Whereas the Low Level is a direct feed from the LFE in the Lexicon. But I thought they ran concurrently... Guess I need to understand more. Am I way off?

-Fauzi


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## Moonfly (Aug 1, 2008)

The high level connection reads the bass content in the speaker outputs, and reproduces this according to the crossover set on the sub itself. In a bass managed system it depends where the bass is being sent as to which method your sub will use. Both connections are permanently active, but since your processor dictates where the bass is sent, then it dictates which connection on the sub is in use at any particular time.

If you have your crossovers set to say 80hz (and so your main speakers set to small), then all bass at 80hz and below is diverted from the main speakers and is sent via the LFE connection. As such there will be no sub 80hz bass in the speakers output for the high level connection to read. Obviously if you set the high level crossover above 80 hz then there would be some content there etc etc.

Still with me?

Now, if you change the mode your processor is running, from bass managed to a more traditional setting for music, as in your speakers are full range, then the LFE output is disengaged and the bass is sent to your speakers. There is now the full amount of bass in your speakers output for the high level connection to feed off. Your sub would now be reproducing bass via the high level connection, and the crossover is dictated on board the sub. In this case, the idea is to match the crossover value to the natural roll off response of the speakers. So if your speakers are good to say 50hz, I would set the high level crossover to about 60hz, listen, and tune by ear till your happy.

Both connections can be used together, but you essentially switch between them using the processor. Generally the LFE connection is the normal way of running a sub these days. The high level is a bit of a throw back from before .1 existed. That said, there are still people who prefer the high level connection, it has a smoother roll of than the LFE method, and a good full range speaker generally sounds more musical run in full range. The high level connection then comes in only to help the main speakers with the low end improving system bass response musically.

You can run either, or both, its entirely upto you. Generally LFE is the preferred way especially as EQ systems like Audyssey are only active here, but if you like the sound of the high level connection, particularly in a musical context (Rel swear by it, and I find Rel subs some of the most musical out there IMO), then using this and switching to it when required is absolutely fine.


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## recruit (May 9, 2009)

Dan - REL subs do actually use both high and low levels simultaneously as opposed to other subs out there, this is one feature that REL do recommend in doing...after owning a Quake/ Q150MKI &MKII / Strata III and Strata V, I did combine the 2 and had good results, well apart from the Quake that is :blush:


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## fauzigarib (Mar 11, 2010)

Moonfly,

Wow! Thanks for the explanation.

So let me get this straight. I use my system for movies 80% of the time and music say 20%. So am I right in doing the following?:

In my movie modes, set the speakers as small, manage the bass at 80 Hz through processor, cross the subs setting at 31 (but this is irrelevant, as the LFE will still play all signals below 80Hz through LFE).

For music, speakers are set as large, lfe turned off in processor, and crossover at 31. This way, only the high level connection is playing in the REL.

Is the above accurate?

Also one other stupid question. On my Lexicon, there is no setting for small or large speakers... only crossovers. So is a speaker that is crossed over at 80 considered large? and say 120 Hz for small? Or is there something else that I need to set to get the large and small settings accurate?

Thanks again, moonfly..

Fauzi


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## Moonfly (Aug 1, 2008)

A large speaker is considered one that will run full range convincingly, so say down to 30hz with authority. You can forget large and small for the sake of argument if you wish, some inferior processors only allow you to set small of large, but yours gives you full control. The 80hz barrier is considered where sub bass becomes omnidirectional so that is where the optimal crossover point is for movies/subs.

If you want to run high level, simply switching your processor to pure audio or something similar (not sure what yours has exactly) would turn off bass management and run your speakers full range, although this is generally a stereo only mode.

For movies, set the LFE crossover on the sub to max. Like you say its irrelevant as the processor dictates what the sub is fed anyway and so wont play anything over 80hz despite what the subs setting is crossed over at. Only the low level needs crossing over on the sub itself.

You pretty much have it all sown up now though :T. Large setting is simply full range for your speakers, so altering their frequency range to max would give you a 'large' speaker setting. If you wanted you can experiment with the high level connection by not using pure audio, but altering your bass management so your speakers play below 80hz, but there are a lot of variables once you start playing like that, which you may or may not want to be bothered exploring.


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## fauzigarib (Mar 11, 2010)

Moonfly,

I thought I had it all sewn up... until your last message! LOL!

I think you and I are saying similar things, but with a slight difference. 

As I understand it, REL recommends that you do the following:
- Leave both connections connected, set the placement, etc, once, and set the sub's x-over frequency initially and leave it there. I have mine set at 31, because that is the frequency I found that sounded the best in my movie room during calibration.
- For movies, have the Lexicon control the bass management by setting the fronts and surrounds to x-over at their appropriate frequencies, so that the LFE sends the appropriate information to the bass. Since the processor is sending only information lower than 80 kHz through the LFE, the bass will get the appropriate information and will play it. 
And since the above is true, the processor will send only information above the 80 Hz range to the mains, which will also reach the sub through the high level connection, but will be irrelevant, as the sub is crossed over at 31.

-For music, it is recommended to turn the LFE output off in the processor (or mute the LFE directly in the REL, as that's also possible), and let the full signal go to the mains and the sub through the high level, and thus the sub will play the information below 31 (I'm not accounting for curve rolloffs, but you get the point.)

Now that is how I understand this crossover business.

What I gathered from your last post was that I should set my subs frequency to the max, and let the processor send the appropriate information, whether watching movies or music.

I guess the reason my way sounds more correct to me is that I'm assuming that ALL information received through the LFE input is played as is, as opposed to the high level connection, which is effected by the crossover that is set in the sub. In other words, the crossover that you set in the sub affects ONLY the high level connection, not the LFE.

Phew, that was a mouthful... How wrong am I?

-Fauzi


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## Moonfly (Aug 1, 2008)

Your correct, if I am reading you correct .

The LFE crossover (on the sub) should be set to off or max to allow the processor to manage the bass. The high level connection should have the crossover set on the sub to match the speakers low end frequency rating, to allow the subs HL connection to manage the bass.


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## Moonfly (Aug 1, 2008)

recruit said:


> Dan - REL subs do actually use both high and low levels simultaneously as opposed to other subs out there, this is one feature that REL do recommend in doing...after owning a Quake/ Q150MKI &MKII / Strata III and Strata V, I did combine the 2 and had good results, well apart from the Quake that is :blush:


Just spotted your post.

I owned a Q100e and a strata 2 so have experience of Rel as well. I know you can use both connections together which is fine, but if you do this via a modern AVR, depending on how you have it set, the AVR will only utilise one connection at a time, unless you specifically tweak all the settings to circumvent this. Typically, these kinds of setting would be out of the norm for a movie focused system setup.


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## recruit (May 9, 2009)

That is what makes the REL's so good with music sources due to it's flexibility for connections both high and low, although unless you move up to Stentor and above ie Studio they struggle to produce the levels of LFE we are used of nowadays...


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## Moonfly (Aug 1, 2008)

I certainly agree with that :T


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## fauzigarib (Mar 11, 2010)

Moonfly said:


> Your correct, if I am reading you correct .
> 
> The LFE crossover (on the sub) should be set to off or max to allow the processor to manage the bass. The high level connection should have the crossover set on the sub to match the speakers low end frequency rating, to allow the subs HL connection to manage the bass.


D,

Here's my confusion. On the control panel of the sub, there is control for only one frequency crossover. Is this the crossover for both connections at the same time? I have always assumed that this was just for the high level connection, whereas the LFE played the signal as it was sent.

Therefore, if there is only one freq control, and that controls the crossover for both connections, I guess I'm forced to have the bass management done by the processor.

Am I correct?

-Fauzi


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## Moonfly (Aug 1, 2008)

Got ya. Most subs have crossovers for both high and low level connections, but like you say yours doesnt. Ive had a quick look at the manual and although it doesnt seem to specifically say if this is the case or not, I would say its pretty safe to assume your correct in that the on board crossover is purely for the HLC :T


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