Speaker positioning - hight

[MO!]

So what's the deal here? I've always heard you're meant to have the tweeter at ear hight. Well, my tweeter is a mere 65cm from the floor! The tweeter is located below the mid/bass. Anyone any idea why this layout is used? Purely for looks? Or is there another reason? Also, is getting them higher worthwhile?

[joel]

Hello MO, how are you?
The ear/brain is very sensitive to the direction of HF sounds, so tweeter positioning *should* be important. However, M**a users in particular have a tendancy to put their tweeters just short of the ceiling, and few floor standers are tall enough to get the tweets up to ear height.
Something that quite a few people do is angle their speakers upwards a little so the tweeters are pointing at their ears.
I don' have this particular problem (or not) as the tweeters on my speakers are at ear height.
One other thing that is often mentioned is distortion from off-axis listening. I don't hear this, either with my system or with real instruments of voices.
YMMV

[MO!]

Hi Joel :D

All is good thankyou, and yourself?

As I said, my tweeters are a mere 65cm from the floor. This would mean i'd have to sit on the floor too if I wished to have them at ear hight! Infact, a little experiment i'll try toMOrow :time: when I can have the volume up to louder volumes! Sitting lower and seeing what difference it makes.

I guess this could be another benefit of putting a few paving slabs under my stands? :D

Cheers

MO :D

:knight: <<<<best *smiley* yet?

[lAmBoY]

If your spkrs have spikes, just make sure the front ones are longer than the rears. Viola, instead HF directionality.

[zanash]

Tweeters at ear height...... when seated !!


Yes you can adjust the "aim" of the hf unit with spikes but that means behind the listening position the best listening arrangements will be higher ! in most cases this is not a problem.

base units above the tweeters create a tilted time alignment dispersion [wrong words]. if you take the voice coil positions of each driver and draw a line perpendicular to them, to touch the start of the first windings, then draw a line at right angles

........
vc bbbb
vc*bbbb
vc bbbb
........
.......tw
...vc*tw
.......tw
........

vc voice coil ... bb lf ... tw hf
imagine a line draw through both * it will angle up, and obviously unit with the reverse the time alignment will be angled down.

This means that the start of each wave, from each drive unit, will be coincident as they leave the speaker along that line of propogation.

You can now start to see why KEF use the uniQ system.

[Dev]

I thought about this when I was looking at Dynaudio's new Contours. The 1.4s have been turned upside down, effectively lowering the tweeter height unless one goes for taller stands (your Missions are another example). Anyone heard them yet?, how do they sound compared to the 1.3s? I'd like to know what difference the lower tweeter has made.

A friend of mine has longer spikes at the front than rear (as Lamboy suggested) so the speakers are pointing up slightly but his speakers are Linn Sara with fairly tall stands. 65cm seems really low. How about putting large paving blocks under the stands for an experiment? I imagine the imaging will improve (or at least be different!).

[Chea Johndle]

Hi MO!,

I hope that I won't get a telling off from the Moderators about this.... it's not advertising as it's not a product....have a look at my website and go to the Tips and Talk section....we have a little write up about our experiances in speaker positioning. We have had some feedback from people who have tried our method of setting up and in each case it has been very positive. Give it a go and let me know if you have a result.

Regards

[lowrider]

Some people, and some speaker brands, including SF, recommend that the ear level should be between the tweeter and the woofer/mid, and I like them that way, raises the stage... :MILD:

[test tone]

Ear height for preference. The tweets of each speaker being equidistant from the floor being of equal import. With speakers voiced for nearfield/monitor applications it may be beneficial for the listening position to be slightly below the tweets (and a worthwhile experiment for 'standard' speakers also).

Naturally, this simple advice does not account for the proximity of room boudaries and 'essential' furnishings. A factor that can only be addressed by the individual in his/her own listening room. But, one area that is often ill-addressed is that between the speakers and the listening position. It often being filled with all manner of acoustically inept detritus. In fact, the only accceptable thing to have between the speakers and listening position is fresh air.

[LiloLee]

In fact, the only accceptable thing to have between the speakers and listening position is fresh air.
Completely disagree with this one. The best thing is probably a coffee table to break up the first floor difraction.

On to tweeter position.

Having the tweeter below the woofer is a very good idea, as long as the designers then tell you how to set up the speaker. Most standounts will be placed on stand usually between 20 and 24 inches in height. With a bottom mounted woofer this probably makes the woofers centre about 26 - 30 inches above the floor. Now measure how far in from the rear wall the speaker usually is. I bet its about the same, as is the distance to the sides. Good recipe for B O O M . Now with the inverted woofer, it is like ly to be about 6 inches higher and less chance of wall boundry effects....maybe:confused:

[timpy]

I guess this could be another benefit of putting a few paving slabs under my stands?

My dealer recommended Mana soundbases for my Tannoy DC2000s (75cm tall with the tweeter in the centre of an 8" driver, so a fair way down the cabinet).

Yes really.

I didn't get any because I was after something cheaper, but nevertheless, they were reccomended to me.

Thought I'd better mention in so as not to show any undue bias. Dealer in question is one of the few Mana dealers to be found.

;)

Cheers

[test tone]

Originally posted by LiloLee
The best thing is probably a coffee table to break up the first floor difraction.

What?. 'First floor diffraction' - this makes no sense whatsoever. I can only assume that you may have been referring to the axial room mode that exists between floor and ceiling?. In which case a coffee table would provide absolutely no benefit. And when in the horizontal plane relative to mid and high frequency dispersion - only detriment.

[GrahamN]

I think Lee may have meant "reflection" - he's been having a few troubles with his worms lately ;) !

IIRC - the man from TACT did recommend either a bit of carpet at the reflection point, or a coffee table or something about 1 third of the way from your to the speaker, i.e. obstructing the reflected sound on its way up to you. I also remember him saying that the ceiling reflection was actually a bigger problem - so time to get carpeting the ceiling folks!

Edit - oh and back to the main point - my tweets are about 110mm from the floor. Gives a nice high and enveloping soundstage - just like being at the front of the gig - although possibly a bit too much so. Hence, I actually have the back spikes a mm or two higher than the front to bring it down a bit.

[lowrider]

I have a coffee table made of wooven straw, both useful and difracts the sound... :MILD:

http://sapp.telepac.pt/lowrider/avback.jpg

[LiloLee]

I think Lee may have meant "reflection" - he's been having a few troubles with his worms lately
See somebody understood me. I'd take up signing but I know I'd definately get that wrong.

[test tone]

Reflection makes even less sense than diffraction.

Think of the speakers as sources of light rather than sources of sound. What happens when the radiated light from each, hits a hard surface such as a coffee table?. It'll mix, reflect, even diffract (creating further reflections). Irregular objects on the table will cause break up, but at what expense?. And any that hits the surface will reflect without break up.

Translate this into a sonic sense and you have artifacts that will interfere with the very necessary processes that determine soundstage/image quality: controlled reverberation, precedence, Haas, etc.

If said table is a necessary domestic fixture then i'd mitigate it's detriment with something like a dense foam pad and/or heavy cloth cover.

[lowrider]

Difraction will enhance ambience, without interfeering with direct sound, unlike reflections, IMHO... :rolleyes:

[LiloLee]

tt

I might have used the wrong word but I stand by what I said. The first reflection will be the strongest and will interfere with the sound more than all of the others.

This is also the main reason that speakers sound better if toe'd in. It is not the pointing of the tweeters at you, it is the breaking up of the rear and side reflections so they will have weaker interference with the main soundwave being produced by the speaker.

These reflections which, when broken down are difractions (using your light analogy) will have less impact on the main sound but add, as lowrider said, to the ambience.

[zanash]

Not certain you've got the tweeter below the woofer bit. In my refference text its to do with time alignment of the drivers, a bit like the old angled front of the spica's.

With bass unit to the top, best stand to get the most from this arrangment, will be lower than the norm. As the previously described arrangment allows the zero delay plane [ZDP] refference axis to be aligned with the listening area. Or cross over correction can be made, or the drive units can be stepped, niether I think have in this case been done [though I stand to be corrected]. If the crossover has an odd order network [1st order], the ZDP axis can be tilt back. If you've not gone to sleep, you can read further on this subject p92 ch7.23 The Accustic Summation: Driver accustic centres and ZDP. Loudspeaker Design by Vance.

Oh yes it make my brain hurt too.

[MO!]

Not fallen asleep, but no idea what you're on about though :D

[garyi]

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.

[GrahamN]

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!)


:rolleyes:

[kermit]

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

:D


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

[MO!]

Originally posted by kermit
:D


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 :D
:spank: :whip: :groupies: :buddies:

[test tone]

The impression of whats happening between the speakers is just that. Things in between the speakers should not make a jot of difference

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...

in other words, your brain is fooling you

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

The point of the coffee table is to obstruct the reflection from the floor

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.

[LiloLee]

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.

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.

[GrahamN]

Originally posted by LiloLee
Thirdly all I've read from you so far is 'I disagree'.
...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?

[zanash]

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 !

[osama]

Originally posted by LiloLee
How about putting some fact to what you are saying ie what effect does a carpet have as opposed to a coffee table.

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.

[zanash]

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 !!

[MO!]

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!

[test tone]

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.

Anyone mention Don Quixote and windmills?

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

[LiloLee]

Anyone using bare, hard surface flooring in a listeing room is not; in my opinion, serious about reproduction quality.
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 :rolleyes:

[test tone]

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

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.

[LiloLee]

So, you want to live in an anechoic chamber :D

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.

[test tone]

So, you want to live in an anechoic chamber :D

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.

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

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.

Glad we are back on good terms.

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

[LiloLee]

I've always thought these looked pretty funky
http://melhuish.org/audio/images/DIY42room2.JPG

[test tone]

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.

[wadia-miester]

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?

[lowrider]

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

[GrahamN]

Originally posted by wadia-miester
Might give us a few area's we can recommend, that maybe you haven't thought of?

..or quite possibly....maybe he's even got something no-one here's considered before :rolleyes:

[wadia-miester]

I give up :banghead: I do try, but well, hey it's sunday and mellow day, and I was being polite too :)

[test tone]

I'm not a regular visitor to the forum, and i'm absolutely not an regular poster. I'd assume that's why i'm now failing to follow the last few posts. Hasn't this thread been 'done', so to speak?. There not necessarily being conclusions, rather there being several strongly voiced opinions. Followed by myself and LiloLee with a couple of amiable posts regarding some wall diffusors.

Might give us a few area's we can recommend, that maybe you haven't thought of?

Cable performance perhaps?. I haven't thought about that for years, since I stopped designing and researching them. In fact, it would be fair to say that i've thought nothing of cable performance since.

[Lt Cdr Data]

Lee...mission said in some literature it was to do with time alignment.....but it will obviously change the distance the bass unit is from the floor with all those attendant effects...

for the question as to how tweeter top or bottom makes any difference, imagine you have a 2 way with the tweeter on top at ear level....draw a line on paper from your ear to a blob....this blob is the tweeter....put another blob direct below...this is woofer ...draw a line from the tweet blob to woof...now there is a space from your ear to the woofer, draw a line...this is a diagonal of a triangle..remember pythagoras that the hypotenuse...is the longest side...this is the diagonal...ie ear to the woofer and is longer than the ear to tweeter...
..so if you reverse it and the woofer is at ear height and the tweeter below, you are making the tweeter further away...
now the tweeter is less deep than the woofer, so time takes less to arrive...now if tweet is on top, then its nearer via your line, and the sound centre is nearer, too as the voice coil is further forward...
but if you make it below, hopefully the time from tweeter to ear will be same as from woofer, as tweeter is made further away...if this makes sense!!

most speakers these days are designed time aligned( one would hope) I have found tho' it does make speakers more open if they are tilted up slightly...that is assuming tweeter on top...

crossover design is complicated..you can make many different values and they all measure flat..at higher frequencies, the baffle reinforces the bass drivers output, and this has to be accounted for, too...its called the baffle step effect...I don't think your average man in the street has any idea about the intricacies..

refraction is bending of a wave passing thro a different medium...

eg air/water..

relection is obviously that..but won't putting a table in between still reflect the sound up to you..effectively raising the floor height....

the listening room is a big problem, and I have not got an ideal one...i haven't done anything to it....soft surfaces are for hf absorbtion, as these get absorbed quick due to low energy...imagine an empty room and it is reflective....reverberation...
breaking up room modes is another thing and is to do with bass reinforcement and booms....this is where you need to scatter to reflections, not absorb them.....tho that would help..I don't know much about this...and havne't xperimented yet...

[MO!]

Originally posted by Lt Cdr Data
Lee...mission said in some literature it was to do with time alignment.....but it will obviously change the distance the bass unit is from the floor with all those attendant effects...

for the question as to how tweeter top or bottom makes any difference, imagine you have a 2 way with the tweeter on top at ear level....draw a line on paper from your ear to a blob....this blob is the tweeter....put another blob direct below...this is woofer ...draw a line from the tweet blob to woof...now there is a space from your ear to the woofer, draw a line...this is a diagonal of a triangle..remember pythagoras that the hypotenuse...is the longest side...this is the diagonal...ie ear to the woofer and is longer than the ear to tweeter...
..so if you reverse it and the woofer is at ear height and the tweeter below, you are making the tweeter further away...
now the tweeter is less deep than the woofer, so time takes less to arrive...now if tweet is on top, then its nearer via your line, and the sound centre is nearer, too as the voice coil is further forward...
but if you make it below, hopefully the time from tweeter to ear will be same as from woofer, as tweeter is made further away...if this makes sense!!

most speakers these days are designed time aligned( one would hope) I have found tho' it does make speakers more open if they are tilted up slightly...that is assuming tweeter on top...

crossover design is complicated..you can make many different values and they all measure flat..at higher frequencies, the baffle reinforces the bass drivers output, and this has to be accounted for, too...its called the baffle step effect...I don't think your average man in the street has any idea about the intricacies..

refraction is bending of a wave passing thro a different medium...

eg air/water..

relection is obviously that..but won't putting a table in between still reflect the sound up to you..effectively raising the floor height....

the listening room is a big problem, and I have not got an ideal one...i haven't done anything to it....soft surfaces are for hf absorbtion, as these get absorbed quick due to low energy...imagine an empty room and it is reflective....reverberation...
breaking up room modes is another thing and is to do with bass reinforcement and booms....this is where you need to scatter to reflections, not absorb them.....tho that would help..I don't know much about this...and havne't xperimented yet...

Gotcha!!!

OK, I appreciate that hf will get to you faster than lf, and that the non perpendicular driver will take longer to reach the listner than if it was perp'. But with the average gap between the two drivers being so small, surely the gap would unnoticable? I'm not aware of any sorts of distance/time figures, but surely that gap isn't audible? Or is it?

[Onno]

But with the average gap between the two drivers being so small, surely the gap would unnoticable? I'm not aware of any sorts of distance/time figures, but surely that gap isn't audible? Or is it?

Well this depends on the frequency. Low Frequency signals have a wavelength of several metres so adifference of a few mm is not going to be noticable. Let's calculate a bit...

for a signal of 100 Hz:
Sound travels at 300 Metres a second. 100 Hz means 100 waves a second so a wave is 300/100 = 3 metres long.

now for a 10000 Hz sound:
again at 300 m/s this signal has a wavelength of 300/10000= 0.03 metres. Three centimetres which means a distance difference of 15 mm will now result in a phase shift of half a wave or 180 degrees. This could be audible.

[Decca]

Most tweeters are designed to be at ear height, however, it is not a fixed rule. Some sound better above or below ear level, a little experimentation is required.

As for room acoustics, this is highly complicated issue. It is the interactions with the room which provide a sense of space which is pleasing to the ear/brain. Reflections are important in music but they must be managed.

A hard floor can create some problems but can be minimised by speaker hight and placement, it is the same for hard ceilings. Domestic considerations do play a part, how many rooms apply diffusers or other devices to a ceiling? My guess is very few. In most rooms the interaction with the ceiling is quite low compared to wall reflections which tend to dominate reflected sounds.

Overkill on reflection control will kill the acoustics in a room and consequently the sound quality as well.

[test tone]

relection is obviously that..but won't putting a table in between still reflect the sound up to you..effectively raising the floor height....

Yes, at frequencies whose wavelength equates to the size of said table. Those frequencies whose wavelength is greater than the table will not 'see' it (although these are likely to be of a size considered modal, rather than reflective in terms of first reflection points). Naturally, the table surface may be absorptive and/or diffuse, depending on any covering.

the listening room is a big problem, and I have not got an ideal one...i haven't done anything to it....soft surfaces are for hf absorbtion, as these get absorbed quick due to low energy...imagine an empty room and it is reflective....reverberation...breaking up room modes is another thing and is to do with bass reinforcement and booms....this is where you need to scatter to reflections, not absorb them.....tho that would help

In terms of providing enough absorption to satisfy T60 (reverberation time - time taken for a sound to decay by 60dB), most (unless one follows a minimalist ideal) rooms probably have enough (defined by the number of Sabins - as in Sabine, the fellow responsible for much pioneering acoustical work, including the T60 formulae). The primary use of additional absorbents, then, comes from treating primary reflections. Hence, being generally additional, the need to control their use in order that the room does not become overly 'dead'.

Modal response is a given - relative to a room's dimensions - and impossible to treat with spot diffusion. Much better, then, to negate the influence of modal response with careful speaker/listening position set-up, perhaps allied to a bass trap or two.

..I don't know much about this...and havne't xperimented yet...

Please do - the potential is very real.

how many rooms apply diffusers or other devices to a ceiling?

I have a diffusor at the primary ceiling reflection point. Depending on room dimensions and speaker location, the ceiling maybe the second primary reflection, after the floor, to reach the listening position. It's treatment, therefore, should be given due consideration.

Overkill on reflection control will kill the acoustics in a room and consequently the sound quality as well.

Very true, and the reason why; after calculating room absorption, I chose a diffusor for the ceiling - much more complex to build and install, but ultimately worthwhile.

[bottleneck]

Originally posted by test tone




Very true, and the reason why; after calculating room absorption, I chose a diffusor for the ceiling - much more complex to build and install, but ultimately worthwhile.


Audiophile grade artex? :D

[test tone]

Audiophile grade artex? :D

Yes, from Russ Andrews, £500/bag.

Has hyper-pure (natch) copper strands in the mix to combat any devious RFI that may emit from the rooms above. Most useful if one uses a radio alarm clock in the bedroom.

Comes complete with a reflection-phase-grating stippler ;)