Adding sub to "full range"...

**glaufman** · **03-26-08, 02:51 PM**

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Mike Cason wrote:

Well, I don't have an arguement with the Dolby link because I'm certainly not a pro. I'm just a novice builder but have built a system that everyone who has listened to it says it's the finest sounding they have ever heard, bar none. I'm just providing you with the settings that I've found to give me the most, and best, sound I can get with my system. I usually listen to music and some concerts in two channel only because the mains are so good.

My Rotel has the sub output and that's the one I use. I am to assume that is the LFE rca jack as well.

Like I said, I was getting semantic, and I don't know the Rotel, but most amps will have a sub output, but not an LFE output... they're different.

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As far as bass guitar reproduction,

good luck with the Reckhorn... as for bass guitar, and the other instruments, the question was really what frequencies the lowest fundamentals run down to...

**Mike Cason** · **03-26-08, 04:59 PM**

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tonyvdb wrote:

The 80Hz crossover setting is the standard set by THX. Although this may seem high it is the best compromise as a good sub will easily handle the rest. I understand your concern for letting the mains do what they can do but this puts more strain on the receivers amp/power supply section and this in turn limits the maximum output the receiver can do for the surrounds.
The mains I have play down to 32Hz and in pure two channel mode they sound great but for movies I dont want that. Remember that even with a crossover setting of 80Hz this does not mean the frequencies below that dont get through it just means that at 80hz the curve will then fall off so blow 50hz there is no output. Does your receiver not have an independent eq for the mains? You could then just roll off the frequencies below 30hz.

I've played with the 80hz setting and it affects the sound quality of my mains. I've paralleled two Lambda TD12s drivers in each main, as well as the Scan Speaks I have for my mids. The mains aren't as detailed with the higher setting, so I'm very happy with the 60hz. The two Lambdas in parallel can reproduce the 60 to 80hz much better than the sub. As far as what THX recommends, it is just that, a recommendation. The end user tweaks their system for their optimal performance and pleasure.

I don't have a crossover adjustment for the mains.

My Rotel processor/amp is a very high current amplifier and can easily power my mains, center, and two surrounds. I have a separate amplifier for my two center backs.

This is not to be taken as an arguement, but rather a discussion. That's why we have our forums to share information with each other.

Mike

**tonyvdb** · **03-26-08, 05:11 PM**

Quote:

Mike Cason wrote:

This is not to be taken as an arguement, but rather a discussion. That's why we have our forums to share information with each other.

Mike

Sorry Mike, no argument was intended here I was just stating what I know and what usually works.
At this moment I have my mains set for Full with no crossover as my sub is a little week and I have a separate amp driving them but this will change once I get my SVS PB13 Ultra.

**superchad** · **03-26-08, 05:21 PM**

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atledreier wrote:

I have very capable fronts. They can easily handle 40Hz at reference, and lower down if I don't go mental. Still, they sound so much sweeter when I cross them over at 80Hz. A properly set up subwoofer will "always" outperform a fullrange speaker down low. You are not using your system to it's full potential if you DON'T cross them over at 80Hz.

You are wrong plain and simple, if your system sounds better crossed over at 80HZ maybe that works for you but in my system it isnt the case, with my power reserves, speakers that go down to 16Hz.... bi-amps with outboard active crossover, 80Hz isnt the way to go. What works in your system does not become an absolute rule.

**Mike Cason** · **03-26-08, 05:25 PM**

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tonyvdb wrote:

Sorry Mike, no argument was intended here I was just stating what I know and what usually works.
At this moment I have my mains set for Full with no crossover as my sub is a little week and I have a separate amp driving them but this will change once I get my SVS PB13 Ultra.

I understand your point and is well taken.

You will love your SVS subs. I've heard a lot of good things about them..

I broke all the rules by putting two RLP 15s in a 5 cu ft box with 4 passive radiators each, but the results are fantastic. I have a lot of rebuilds, (total of 5 for the sub alone) starting 3 or 4 years ago to achieve the sound I am most happy with.....we call this stuff DIY and we are supposed to enjoy our projects.

BTW....The Lambda line of woofers and subwoofers were custom designed, machined, and built in Florida and as far as I could tell, was one of the highest sought after driver in the world. Nick didn't charge enough for them and eventually sold out. I was negotiating purchasing the business and inventory from him but am lacking in the audio technical department to make a success with their continued production.

**atledreier** · **03-27-08, 01:52 AM**

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superchad wrote:

You are wrong plain and simple, if your system sounds better crossed over at 80HZ maybe that works for you but in my system it isnt the case, with my power reserves, speakers that go down to 16Hz.... bi-amps with outboard active crossover, 80Hz isnt the way to go. What works in your system does not become an absolute rule.

This is exactly why I put the 'always' in quotes. Not many have mains that will play comfortably in the lower ranges. I have no signs of strain when playing low stuff on them, they have no problem handling music on their own, but even so they are sweeter and cleaner up high with the lower end crossed off. I would think that about most systems really, regardless of quality. I have good headroom, a bi-amped setup and not a very big room to fill.

**superchad** · **03-27-08, 02:12 AM**

sorry I didnt see quotes but all the same I think in general you are correct but for those of us with true full range and various other equipment that is not really the norm the 80hz rule doesnt apply. I didnt want to start a debate just adding that there are almost always exceptions to even the most universally believed rules of thumb, if my goal wasnt a music first system I believe I would probably be firmly in the 80hz camp with most others......cheers

**jakewash** · **03-27-08, 04:32 AM**

Wasn't that 80hz cross over thing brought out/setup by THX anyway?

IMO, it really has no basis when it comes to music systems unless your system can not handle frequencies below that with authority. Speakers should be set up as dictated by the capabilities of each speaker or system and the way each individual likes, as that is all that really matters.

**hddummy** · **03-27-08, 05:35 AM**

This one has taken on a mind of it's own. Let's summarize. 80Hz crossover is a good rule of thumb for "movie centric" systems but is still largely determined by personal taste and system capability. If you don't have the time or necessary resources to test your system out, set it and forget it. If you want to play around with different frequencies...by all means. For "music centric systems", many prefer to leave full range speakers handle the bulk of the low end material but will probably need to crossover to a sub and some level. Again...do some testing.

Now...as for glaufman's original question... Have we sufficiently turned you around enough so that you have no idea where the donkey's tail needs to go?

**glaufman** · **03-27-08, 06:56 AM**

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tonyvdb wrote:

The 80Hz crossover setting is the standard set by THX. Although this may seem high it is the best compromise as a good sub will easily handle the rest.

Although I believe in THX, this is one area where I differ from their opinion... I prefer a lower crossover...

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I understand your concern for letting the mains do what they can do but this puts more strain on the receivers amp/power supply section and this in turn limits the maximum output the receiver can do for the surrounds.

I don't believe my receiver is being strained, and I certainly have plenty of output room for the surrounds...

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Does your receiver not have an independent eq for the mains? You could then just roll off the frequencies below 30hz.

It does, but the characteristic is limited to the point where I don't think this is practical... it's only 3 band, the bass and treble can only adjust levels and cutoffs, (high for the bass, low for the treble) and level and center for the mid, without an adjustment for Q or BW...

**glaufman** · **03-27-08, 07:46 AM**

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salvasol wrote:

Do you have the option on your receiver to send the sub output to main speakers and sub at the same time???? ... my Yamaha RXV 2700 has that option, I'm using JBL Stadiums for the main front, they go down to 35Hz; so what I did is to set them to small (according to manual, it doesn't matter if they're set to small or large when using for sub output), crossover to 80HZ and sub output send to Both (front speakers and Sub)

I don't think I understand... if the mains are set to 80Hz, shouldn't anything below that be sent only to the sub? You can set the mains to 80 and still get the sub output sent to the mains? that doesn't seem to make sense...

**hddummy** · **03-27-08, 08:41 AM**

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glaufman wrote:

I don't think I understand... if the mains are set to 80Hz, shouldn't anything below that be sent only to the sub? You can set the mains to 80 and still get the sub output sent to the mains? that doesn't seem to make sense...

That does seem somewhat counter intuitive, but I think what happens is that both the sub and mains get material below the crossover and LFE. In other words, the mains get full spectrum and LFE. The sub gets low frequency material from the mains and LFE. You'd better have some serious capability on the mains to handle that.

**superchad** · **03-27-08, 07:08 PM**

I run full plus sub in my Rotel, it is useful when you have full range fronts for extra depth in the presentaion but center and all surrounds follow what ever cross over you set. If my speakers couldnt handle bas as low as they do (Iam down -10db at 16Hz) I wouldnt use this feature as it could be a woofer killer.

**glaufman** · **03-28-08, 07:06 AM**

Quote:

hddummy wrote:

Now...as for glaufman's original question... Have we sufficiently turned you around enough so that you have no idea where the donkey's tail needs to go?

Actually, I think I have a direection as to how I'll probably go, at least to start, which'll be to use the 60Hz crossover the rcvr allows, and see how it sounds, since noone argued (at least not that I've read yet) with the assertion of staying away from the speaker's cutoff in any case... I'd still like to hear opinions on that, and answers to some of the questions that raised in my mind, basically...
How much room is adequate to keep the crossover above the mains' cutoff?
The other questions it raised, such as is the receiver supposed to do this itself, I can answer empirically, once the wife goes away for a few days...

The only question left really will be whether I make sure to get a sub with high level in/outs, so I can eventually use its crossover to power the mains in case I decide I need ot listen to that to see if it's better, and what people think, if the crossover in these subs has characteristics sufficiently flat etc to do this effectively, or if it's a gimmick to stay away from...

**glaufman** · **03-28-08, 07:12 AM**

Quote:

hddummy wrote:

That does seem somewhat counter intuitive, but I think what happens is that both the sub and mains get material below the crossover and LFE. In other words, the mains get full spectrum and LFE. The sub gets low frequency material from the mains and LFE. You'd better have some serious capability on the mains to handle that.

I think that depends on how the receiver is designed, and how you've set it up...
Theoretically, the receiver is under no obligation to send LFE to the sub... if you tell the receiver your mains are "large," that implies full range, in which case it can very well send the entire LFE to the mains and nothing to the sub... (according to Dolby) ... if all the sats are set to small with a crossover, then the rcvr should transistion via opposing rolloffs from sats to sub at that rolloff... not that the mains shouldn't get anything below that freq, they have to in order to make the transition smooth, but the signal they're given should rolloff... another question becomes at what slop do they rolloff? 1st order, 2nd order, etc... (6 db, 12 db per octave, 20, 40 db per decade?) I plan to run some tests on my AVR to see what it actually does... I'll post the results if anyone's interested, but due to other projects it may be a while before I get around to it...

**glaufman** · **03-28-08, 07:16 AM**

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superchad wrote:

I run full plus sub in my Rotel, it is useful when you have full range fronts for extra depth in the presentaion but center and all surrounds follow what ever cross over you set. If my speakers couldnt handle bas as low as they do (Iam down -10db at 16Hz) I wouldnt use this feature as it could be a woofer killer.

that's one thing I'm afraid I'm doing now, which is one reason I want to add the sub, is certain scenes seem to be doing things to my fronts, that I don't pick up when I run a scan, so I don't think it's room acoustics, but rather trying to play freqs that are too far down their slope to hear effectively, so my LFE mix is turned way up... of course, it could simply be listening to the harmonics with a severely reduced fundamental, since it's so far down their slope... I really have to turn that LFE down and see what happens...

not enough hours in the day...

**SQCherokee** · **03-28-08, 09:46 AM**

From the research I have done when 5.1 surrround was originaly demoed they had a subwoofer associated with each channel then something bigger for the .1...so I would find a way to add a sub to all of the channels...then happyness will ensue.

**glaufman** · **03-28-08, 03:05 PM**

Quote:

SQCherokee wrote:

From the research I have done when 5.1 surrround was originaly demoed they had a subwoofer associated with each channel then something bigger for the .1...so I would find a way to add a sub to all of the channels...then happyness will ensue.

Well, I'm a full believer in themore subs the better... (pay no attention to the fact that I have yet to own one)...

My ultimate goal is a sub underneath each and every seating position...

Anyone who want ot give me a job that'll let me afford that I'm soliciting offers...

**tonyvdb** · **03-28-08, 03:16 PM**

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glaufman wrote:

My ultimate goal is a sub underneath each and every seating position...

Your looking at lots of issues with that idea. Phase cancellation being one of the biggest. Your far better off adding one Butt kicker to each chair/sofa.

Multiple subs installed improperly and set up wrong will not improve bass response and will most likely cause huge dips and peaks in the room of the frequency response. Room treatment, placement and base trapping becomes crucial.

**superchad** · **03-28-08, 05:04 PM**

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tonyvdb wrote:

Your looking at lots of issues with that idea. Phase cancellation being one of the biggest. Your far better off adding one Butt kicker to each chair/sofa.

Multiple subs installed improperly and set up wrong will not improve bass response and will most likely cause huge dips and peaks in the room of the frequency response. Room treatment, placement and base trapping becomes crucial.

I couldnt agree more, more subs can just add more problems if not done right.... not only is a Butt-Kicker going to give you the same percieved result it is going to be alot cheaper, I have Aura Bass Shakers in all my chairs and they work great....they only cost me $10 for each unit. I have heard (felt) the Butt Kicker units and they perform no better than the Bass Shaker but the cost 20x as much, they are both bass resonator units but also the Bass Shakers are much smaller and easier to integrate IMO.
Dont let the Bass Shakers price fool you, I want the best performance possible for the money and have a system with over $20,000 in equipment, I refrence this to assure you I would pay for the Butt Kicker units if I thought they were better or worth it. I am not sure if Bass Shakers are available anymore as I seem to remember I got them cheap on closeout special. They sat in their boxes for over 2 years before I installed, my friend turned me onto them and has them installed in his seats. No matter which unit these are going to be a better and easier to work with....and cheaper solution you need to explore. Cheers

**bone215** · **04-24-08, 09:52 PM**

Seems like alot of different experiences. My experience using two stereo subs up front underneath my main L and R speakers differs. I used four different types of speakers and in each case I found that running into the sub first, and then from sub up to speaker using hi level line out was best. The subs default was to send everything above 150Hz to the speakers so in this case the subs were handling alot. There was no localization issues since the subs were directly below the speakers. The set up, in essence, made a full range speaker system good down to 22Hz. Once I got past the thought of how high I thought 150Hz was, I never looked back.
I tried various other hook ups and different crossover settings, but overall, running the subs the way I did sounded best=for me in my room.

Many speakers use a large woofer and they play pretty high up into the frequency ranges. Its not like a 12 or 15 can't play that high.

The room and placement plays a large role.

**mayhem13** · **04-24-08, 10:29 PM**

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bone215 wrote:

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