Speaker positioning - hight

I think you are all on dodgy ground.

The impression of whats happening between the speakers is just that. Things in between the speakers should not make a jot of difference, exept in the context of the room. I.E. that coffee table could be anywhere perfroming the same task.

the only cavet to this is if your speakers fire to the side, i.e. towards the centre.

A simple test is to listen to music in the pitch black, you won't here any difference with or without the table, in other words, your brain is fooling you.

 

Oh dear....how much can be misunderstood by so many....

Were not talking about whether anything between the speakers has any effect, but between each speaker and the listening position.

The point of the coffee table is to obstruct the reflection from the floor (if you're really that bothered). The suggested way of positioning it was to
a) get a mirror,
b) place it on the floor so you could see the tweeters in it from your listening position
c) place the coffee table (or whatever) so you then could not see the mirror.
(I really hope I don't have to explain that you're not then supposed to be able to see the tweeters in a mirror on the coffee table top!)

This does assume that sound does behave like light, which of course it doesn't - try seeing round a corner! - but it's a first approximation. The whole point is to obstruct the reflected soundwave - the different direction and time delay between it and the principal/direct soundwave is what confuses the ear and disturbs the image location - or at least reflect it back on to the floor so that the extra reflections and associated dispersion diffuse the echo.

Of course it doesn't work with Naim speakers, which seem to obey different laws of physics than the rest of us. (Or at the very least, their owners do!)

 

i,ve got my mirror on the ceiling , what do i do next........

 

Dim the lights, put on either some Marvin, White, or even Sigur Ros, or hey Marilyn Manson if you're up for it! Do a few reps to get toned then........ something about birds and bees
:spank: :whip: :groupies: :buddies:

 

That would only follow if the speaker's dispersion was beam-like from the front of the speaker, directly to one's ears. It isn't, which means that sound will interact with anything adjacent to, and behind, the source (speaker). This will effect the measured system response, but whether the measured response is audible or not...

We rely on the brain fooling us in order to perceive sonic quality.

Let's deal with the reflection first. Yes, it's valid, if not of the same importance as that from adjacent walls. However, the validity really only extends to rooms with bare, hard surface flooring, which really shouldn't be a factor in a listening room. Any form of carpet, strategically placed rugs (etc), and the reflection quite probably ceases to be an issue.

If we assume the bare floor scenario to be too unlikely to contemplate, what then the placement of a coffee table in situation where it is unnecessary?. Unless it is acoustically inert (highly unlikely), then it can only serve to cause detriment. Despite objections to the contrary, light and sound share characteristics of transmission for my earlier analogy to stand. Hence you have an acoustically reflective surface between the speakers and the listener. A situation deemed acceptable only by those lacking elementary acoustical knowledge.

ps: Those wishing to perform more acceptable means of treatment in this area should use the mirror for each speaker seperately, and treat with a rug, etc. Mirror points on the ceiling may be more valid, especially if the ceiling is low. Treatment here is not necessarily simple or visually acceptable. It may be possible to use some form of basic moulding to offer a degree of dispersion rather than absorption.

 

For one why is the floor reflection of less importance than the side walls?

Secondly I have laminate flooring.

Thirdly all I've read from you so far is 'I disagree'. How about putting some fact to what you are saying ie what effect does a carpet have as opposed to a coffee table.

 

...but the really strange thing is that he then goes on to agree with most of what we've said...
a) reflections should be avoided if possible
b) carpet/rug is a good idea at the reflection point - and similar kind of diffuser on the ceiling too if domestic/aesthetics permit
c) light and sound don't behave identically, but it's a good enough analogy for a first approximation
d) you already suggested a toe in to avoid reflection from the side walls.

Anyone mention Don Quixote and windmills?

 

I think some of these post have gone off topic.

Mo asks what is the rational for having the bass unit above the tweeter. Now I've give the scientific[?] explanation, I've refferenced my source, so I do not really certain what more I can do if Mo can't follow .....hum.

Quite what coffee tables have to do with this I can't imagine......[I do really] first refections etc are important aspect, but do not answer the question asked !

 

I think carpets help in absorbing sounds and damping them as opposed to a coffee table that diffuses sound, just like the bookcase trick, and prevents the tendency for the bass in particular to get boomy.

 

You can use the mirror trick..... to find the right place to site the carpet,cat small dog, ardvaark etc to lessen the first reflection.

Place one mirror on the ceiling ..no no no.

Place one mirror on the floor and sit in your listening position, move mirror about till you see the tweeter in the reflection. The position of the mirror is the place on the floor that might need treating. You can do the same for walls, but you need a willing assistant to hold the mirror in place.

So.......I'm off topic now too !!

 

I'm greatful or your explination zanash, and I hope it didn't seem otherwise? I think I understand that basicaly it means that the sound will get to you at the same time, but why this is different between having it on top or bottom is beyond me.

As for your "You can use the mirror trick..... to find the right place to site the carpet,cat small dog, ardvaark etc to lessen the first reflection." I think my dog is aware of this as she always tends to lay infront of my speakers! She digs them funky beats!

 

Perhaps we should ignore acoustics for the moment and debate the readiness with which hifi fora threads turn to bitterness?

Maybe later. In the mean time:

The information regarding reflection is a given. My argument was only ever concerned with contesting clear space between the speakers versus the use of a coffee table. My arguments were made abundantly clear. Anyone using bare, hard surface flooring in a listeing room is not; in my opinion, serious about reproduction quality. Therefore I negate floor reflections as a consequence of carpetting, etc. Hence wall reflections are - rightly - considered pre-eminent. However, I make no apology for a lack of understanding on behalf of the reader.

Very good. Me and the Man Of La Mancha - seemingly mad - chasing the impossible dream of sensible, technical discussion in a land of subjectivism.

 

So do you have carpet on your walls and ceiling then.

And no I don't take reproduction quality seriously, it's far more fun that way

 

No, I have DIY designed absorption panels (using the highly effective rockwool) either side of the speakers, and another behind my listening position. I have DIY mouldings on the ceiling. My floor is carpetted so needs no individual treatment. The one and only door to said room has also been sound deadened, and filled with rockwool (without doubt the most obvious improvement).

Personally, I wouldn't use 'fun' with regard to my system. But then (and for my sins!) i'm not simply in it for the music, I also want absolute and unerring accuracy too. Of course, my system falls short in many respects, but I know (in most cases) why, and through increased understanding, can seek to identify genuine means of improvement.

 

So, you want to live in an anechoic chamber

Glad we are back on good terms.

Unfortunately I threw away the edition of HFN which had an atricle about room reflections. IIRC it considered the rear wall the most dominant and caused most problems, followed by the wall behind your listening position. This was because they had the most effect on the sound coming towards you as +ve & -ve addition to the soundwave.

It felt that with toe in the side walls will add to the ambience and not predominate too much.

 

No, not at all. I've only ever considered it necessary in my room to eliminate/negate potential sources of detriment. At the same time leaving some potential for tuning through system set up.

There is also a great deal of opinion that any absorption used to treat side wall reflection is best experimented with, in terms of density, coverage, etc. I built my panels to be used at the mirror points, but prior to final fixing, decided to have them free-standing. This was only meant to be a temporary measure, but i've had good results from non-symetrical placement of them so far. So, it's likely they'll stay as is, and be part of the tuning I mentioned above.

Echo that. It's good that topics like this can be discussed with strong opinion, but that we depart without ill feeling :MILD:

 

I've always thought these looked pretty funky

 

I've seen that picture before. Then I was looking at the speakers. I've spent some considerable time over the years at James Melhuish's site researching suitable enclosures for a full range design of my own.

But, in the context of this thread, then yes i'd agree that the diffusors do look the part. It certainly helps to integrate something like this into the room when they have a sculptural appearance, as these certainly do.

 

Sounds like you are prime candidate for a TACT system sir
Test Tone, could you for the sake of the late comers here,could you just run through your equipment, mods and acoustics treatments you have made, and what effect they have had, and what you are wishing to achieve. Might give us a few area's we can recommend, that maybe you haven't thought of?

 

Or TMREQ, if you like to do the work and be in control... :MILD: