Speaker Set-up

[darien87]

darien,
The VR2s probably have a similar freq. response. The thing is that at -3dB, you are only getting 50% out of what you put in. At -6db, its only 25%. You may think you’re not using the VR2s full potential, but you are also not using your subs effectively either. Granted, you have some nice gear; well designed, sensitive speakers and robust subs – with the Denon 2805 only having a universal bass management, you also have to consider the freq. response of the other speakers as well. You may not hear much of a difference, but bass management is not just about improving sound quality, but also effective use of power. If you want to run the X-over at 60Hz, then do it. It’s your sytem. BTW, the 2805 has adjustable X-over settings, not fixed 80Hz as the sales guy said.

Thanks for the info.

So I did some more research. I called Denon and you guys are indeed correct in that when you set the fronts to large, even with the crossover set at 60Hz, the fronts get a full range signal. So if you want the fronts to roll off at 60Hz, you have to set them to small.

I decided to test the response of my VR2's. According to Boston, they are rated at 40-20KHz. So I got an 80db baseline and used my Rives test CD to test lower than 40Hz. (I of course turned off my subs). The VR2's put out about 75db at 31Hz! I was pleasantly surprised. It seems Boston rates their speakers fairly conservatively. So I decided to leave the fronts set to small, but I dropped my crossover to 40Hz. I tested it out with the scene of the emergence of the first walker in War of the Worlds and it sounded great.

Now the only thing I'm worried about is the center channel and rears. Denon said that when you set the crossover frequency, EVERY speaker is crossed over at the same frequency. My center is rated down to 65Hz I believe, but my rears are just little bookshelf speakers. But I would assume that the movie mixers would know not to send bass frequencies to the center or surrounds. Just about everyone uses a fairly small speaker for center and surrounds don't they?

 

[shokhead]

You know you receiver has to work harder to get those mains down to 40. I would at least put it at 60 for the other speakers and to ease up abit on the receiver. Not much lfe directed to the center/surrounds.

 

[QubyB]

More or less bass

Have been reading the bass / LFE / crossover / small-large “dispute” with interest.

Darien, I guess that no matter what would be “theoretical best” or even “scientifical correct”, in the end what counts is the sound that pleases you most no matter what the settings are or “should be”. It is a matter of experimenting and personal taste.

With your original setting of 60Hz (in the receiver and I reckon the cutoff on your sub as high as possible!?) and front-large I can imagine you heard more sound (bass) as opposed to front-small, you actually have doubled your front bass output (not the LFE output) below 60 Hz, for those basses now come from you front speakers (as far as they can manage) plus from the sub. Yes that may increase your bass ... not necessarily so btw, for with bass coming from multiple sources room acoustics start to play a dominant role.

That is the funny thing with all these discussions … what we seem to forget is that room acoustrics and speaker and sub placement and listener position play a far larger role in bass reproduction than all the rest. This has to do with resonance frequencies and standing waves. There will be locations in your room where there is virtuyally no bass of certain freq and places where levels are excessive, differences can be as large as over 15dB. Multiple bass sources generally worsen the problems for the phase differences between the different (3) sources of soundpressure at your hearing position cancel out or amplify several low frequencies. Which is why generally speaking a receiver crossover set at 80Hz (the THX spec) and all speakers to small is a good solution. Now all bass (below 80Hz) from all speakers is directed to one single source of air pressure, the sub, and that generally gives a smoother overall result. I said generally. And I said, no matter what theory says, let your own ears be the judge and pick the settings you like.

A very good article on the subject is: www.harman.com/wp/Loudspeakers&RoomsPt3.pdf
Actually a “must read” for everyone discussing in this thread!

Best regards and have a good time fine tuning. Isn’t this a nice hobby, lots of fun combined with frustration due to your terrible room acoustics that may make your valuable speaker investment sound “boomy” in stead of “tight”?

QubyB

 

[Ethan Winer]

Quby,

> what we seem to forget is that room acoustrics and speaker and sub placement and listener position play a far larger role in bass reproduction than all the rest. <

No kidding.

> differences can be as large as over 15dB. <

I regularly measure 30 dB and more at low frequencies in rooms. All rooms. The reason people sometimes measure less disparity is they're not measuring at a high enough resolution. A typical third octave analysis completely misses the true extent of the peaks and nulls because it doesn't usually hit the exact center frequencies. If you measure to a resolution of 1 Hz you'll then see how bad all rooms really are. The graph below was derived from tones at 1 Hz intervals in a room about 16 by 10 by 7.5 feet. This sort of response is absolutely typical.

--Ethan

 

[QubyB]

No kidding

Ethan, indeed ... no kidding ... you're right, SPL differences over frequency range can be (and often are) larger than 15 dB. Just did not want to exaggerate too much in my first post

I was kinda hoping the dispute that seemed to be going on here about the better settings for small/large and x-over could get directed to the real important and often overlooked issue: room acoustics, which can "ruin" a perfect set of speakers + sub.

Glad you support that view, with evidence even

QubyB

 

[Nick250]

I was kinda hoping the dispute that seemed to be going on here about the better settings for small/large and x-over could get directed to the real important and often overlooked issue: room acoustics, which can "ruin" a perfect set of speakers + sub.
QubyB

QubyB, there are many threads here on AO about room acoustics and correcting them with room treatments and so on. I don't think you will find much disagreement that it is more important than Auto EQ using Audyssey. The focus of this thread however, IMO has been more on the electronic part of setup and tweaking with reagards to AutoEQ using Audyssey on Denons. As the owner of a Denon 3806 in my mind the jury is still out about Denon's Auto EQ.

Welcome to AO QubyB.

Regards, Nick

 

[darien87]

Have been reading the bass / LFE / crossover / small-large “dispute” with interest.

Darien, I guess that no matter what would be “theoretical best” or even “scientifical correct”, in the end what counts is the sound that pleases you most no matter what the settings are or “should be”. It is a matter of experimenting and personal taste.

With your original setting of 60Hz (in the receiver and I reckon the cutoff on your sub as high as possible!?) and front-large I can imagine you heard more sound (bass) as opposed to front-small, you actually have doubled your front bass output (not the LFE output) below 60 Hz, for those basses now come from you front speakers (as far as they can manage) plus from the sub.

You're EXACTLY right there Quby. I was getting quite a bit more mid-bass from my VR2's with them set on large, which is why I didn't like the small setting initially. Even though what everyone was saying about sparing your receiver and speakers made sense, it just didn't sound as good to me. But now that I've tweaked a bit, setting them on small makes more sense. I actually spent about 20 mintues listening to music and switching back and forth between a 40 and 60Hz crossover, and there wasn't much of an audible difference. So I might just go back to setting the crossover at 60Hz to "ease up" on the receiver as Shok suggested. Maybe, maybe not.

 

[QubyB]

Life can be cruel

Hi Darien,

So, you’re reformed now … welcome to the society of “front-small” addicts!

At another forum I read a post of someone who had the same consideration to make, front-large or -small. He got himself a nice set of Klipsch RF7’s that set him back some $2200. They go as low as 32 Hz but in the end he decided he had to set his babies at front-small to get the best result … and it really did hurt to do that he said. Hehe, yeah, life of a hifi/HT hobbyist can be cruel

Isn’t this just part of the fun … all this tuning and tweaking and listening and making up your mind? Just to find out when you put that other favorite CD in the drawer the other settings again sound much better?

Have fun!
QubyB

 

[bpape]

In general, you're best off to leave the xover at 80 Hz. The reasons for this are:

- less strain on the receiver - leaves more head room for short term dynamics
- less strain/distortion on the non-subs
- more freedom of placement with mains.

Many many of the response issues will be at 80Hz and below. If you cross at 40, the ones above that are directly tied to placement of the mains. Crossing over at 80Hz, still allows you to influence response up to say 120Hz or so due to xover slope and overlap to the mains.

If you happen to be one of the lucky few that has mains that will do 30Hz solidly, and a setup physically that happens to yield somewhat smooth bass response with the mains where they also image well and lock to the screen, then you might slide with a 60Hz xover.

Just my 2 cents

Bryan

 

[shokhead]

In general, you're best off to leave the xover at 80 Hz. The reasons for this are:

- less strain on the receiver - leaves more head room for short term dynamics
- less strain/distortion on the non-subs
- more freedom of placement with mains.

Many many of the response issues will be at 80Hz and below. If you cross at 40, the ones above that are directly tied to placement of the mains. Crossing over at 80Hz, still allows you to influence response up to say 120Hz or so due to xover slope and overlap to the mains.

If you happen to be one of the lucky few that has mains that will do 30Hz solidly, and a setup physically that happens to yield somewhat smooth bass response with the mains where they also image well and lock to the screen, then you might slide with a 60Hz xover.

Just my 2 cents

Bryan

80 might be best and might not. I used 80 until i got the AVIA disc and it showed me that 80 dropped off the table edge and 60 smoothed into it.

 

[darien87]

In general, you're best off to leave the xover at 80 Hz. The reasons for this are:

- less strain on the receiver - leaves more head room for short term dynamics
- less strain/distortion on the non-subs
- more freedom of placement with mains.

Many many of the response issues will be at 80Hz and below. If you cross at 40, the ones above that are directly tied to placement of the mains. Crossing over at 80Hz, still allows you to influence response up to say 120Hz or so due to xover slope and overlap to the mains.

If you happen to be one of the lucky few that has mains that will do 30Hz solidly, and a setup physically that happens to yield somewhat smooth bass response with the mains where they also image well and lock to the screen, then you might slide with a 60Hz xover.

Just my 2 cents

Bryan

Unfornately, with my living room, I have NO freedom to move my speakers around. I guess I'm pretty lucky that my frequency response isn't too bad. Maybe, when we finally buy a house with a large living room, I can experiment a bit. For now, I think my system sounds pretty good the way it is. So 60Hz it is for me; for now. Then again, by the time we get a house, I'll probably be in the market for new speakers, and this will start all over again.

 

[billy p]

Hi D87

are you any futher ahead I'm not sure I am? haha..
I'm moving July 07 into vastly larger home and will upgrade the main's to floors so I hope I'll be loaded with answer by then LOL.

 

[bpape]

You're absolutely right. As I said, sometimes you get lucky and can run the xover a little deeper if the speakers/placement/room allow. If 60 works better for you, then go for it.

Bryan

 

[QubyB]

Room acoustics ...

So … I just received my new SPL meter and I measured the frequency response at my listening position. And guess what? I’ve got peaks and valleys with a range of over 20dB! Hehe, so much for worrying about a “neutral” frequency response of the speaker system within +/- 3 dB. That will completely fade in the room response!

Luckily I was able to lower a nasty peak at 50 Hz with some 8 db just by adjusting the phase on the sub, which helped avoiding some bass boom. For the rest I guess I got to live with it. I can’t move the speakers around and can’t change the listening position without completely overhauling the living room set up.

Ah well, although the room characteristics suck, I am pleased with the sound of my new system. “Review” over here:

forums.audioholics.com/forums/showthread.php?t=23566

QubyB

 

[billy p]

OK the verdict for me is in without question my set-up set to small with sub and x-over at 80Hz is even better since I found out about bypassing the sub x-over by turning it up and letting the AVR do the thinking!!!
PS: Thank heavens for all the time I waste(kidding) reading the posts and threads on this site!!

 

[shokhead]

My gosh ya learn something everyday.