A question about room demands on speakers

spiritofmusic

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Jun 13, 2013
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Please make allowances for me if these are stupid qs LOL
When assessing room size and whether things are practical for a particular spkr, spkrs-amps synergy, which of the following list are true or relevant?
Do we consider flr area or volume?
Ie if one lives in a double or triple ht space, or alt in a loft space w descending eaves, do we still only consider the plan area as you would do in a regulation ht 8' room, or does the extra volume in 12'-20' ht absolutely have relevance acoustically, and esp in assessing physical demands on spkrs-amps?
Additionally if one lives in a very big space, and in effect sits in the mid pt of the space and the listening zone is purely the front half of the room, is the rear of the room relevant (other than rear reflections/ambience)?
Ie if one's space is twice the size of another, one sits in the middle of the room, v the other space where you sit right against the back wall, do the spkrs-amps recognise this? Or are they energising the whole space and sound will be v different?
I ask all this because I've just listened to Apogees mate brilliantly w 80W 211s in a standard 18x11x8 room
But my space is a more expansive 18x50x9 loft, where I'll be sitting right at the intersection mid pt of the front and rear of the room
And I'm trying to wk out if 211s and Apogees can replicate their feat here that they did in the 2-3x smaller space
 
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mullard88

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Jun 5, 2010
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I can not answer your questions as I have no background on room acoustics.

But I engaged the services of a professional acoustician to treat my main listening room. The things I learned from him are:
1) bring down the noise level in the room by sealing the room to minimize outside noise from entering
2) the other reason for sealing the room is to prevent sound from escaping as this leads to lost information
3) the center of the room is called the null point, do not put your listening chair here as this is the spot with the least information

I strongly suggest you consult a professional. Room treatment cost is minimal compared to the cost of equipment and accessories.
 

Mike Lavigne

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Marc,

btw, I sit almost exactly mid room in a fairly large (but likely a little less actual cubic meters/feet as yours) room. and so I know what 80 tube watts does in my room on 97db, 7 ohm speakers with 2000 watts on the deep bass. I've had a number of tube amps similar in power to yours. it can be good and satisfying until I go back to my dart mono's and then is revealed to be wanting......but nothing is wrong in a subjective sense while listening. I'd say it's barely 'good enough' to live with. but it does not need to power below 40hz in my room due to the active bass towers.

your main issue is whether your amp-speaker interface can pressurize the room for bass, or will it sound a bit 'lost' on heavier music. and unfortunately; there is no reliable way to know that for sure when you are on the edge of that happening. bass performance is too complicated to predict. and absolutely the bass will be 'sensitive' to the shape, size and particular surface loading and construction.

seeing your space in the pictures (nice space and feel to it, so congrats on that part) 80 watts and medium to somewhat lower than medium efficiency speakers are not likely to pressurize that room......is my SWAG. but I'm just guessing.

then there is the dispersion pattern of a dipole (I assume an Apogee is a dipole) and how that works (the ceiling slant might not be relevant with a dipole). that 'peak' might or might not need taming.
 
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spiritofmusic

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So what do you say if I tell you my current Zus wk great down to 50Hz w my 70W 211s, w bass <50Hz covered by 300W Class D Hypex in built subs/Lundahls transformers?
 

LL21

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Dec 26, 2010
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Marc,

btw, I sit almost exactly mid room in a fairly large (but likely a little less actual cubic meters/feet as yours) room. and so I know what 80 tube watts does in my room on 97db, 7 ohm speakers with 2000 watts on the deep bass. I've had a number of tube amps similar in power to yours. it can be very good and satisfying until I go back to my dart mono's and then is revealed to be wanting......but nothing is wrong in a subjective sense while listening. it's 'good enough'. but it does not need to power below 40hz in my room due to the active bass towers.

your main issue is whether your amp-speaker interface can pressurize the room for bass. and unfortunately; there is no reliable way to know that for sure when you are on the edge of that happening. bass performance is too complicated to predict. and absolutely the bass will be 'sensitive' to the shape, size and particular surface loading and construction.

seeing your space in the pictures (nice space and feel to it, so congrats on that part) 80 watts and medium to somewhat lower than medium efficiency speakers are not likely to pressurize that room......is my SWAG. but I'm just guessing.

then there is the dispersion pattern of a dipole (I assume an Apogee is a dipole) and how that works (the ceiling slant might not be relevant with a dipole). that 'peak' might or might not need taming.

In my far more limited experience, this is very similar to what i just PM'd to Spirit privately. i agree about the pressurization of his room and the Apogees he is looking at. i would have guessed that, if it is going to happen at all...high quality, high levels of current will be required. Or he can consider the larger and legendary Apogee Full Ranges, though i recall someone suggest that the width of his room might require careful consideration for this...cannot exactly recall.

This part of reproduction is not something that is on everyone's priority list, but eventually as one starts to check off all the other 'must have's in audio...eventually scale and effortlessness in filling a room can [for some people] become one of those must have goals. In Spirit's room...why not feel like you've got a small concert going on?
 

spiritofmusic

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Lloyd and Mike
I went into this Duettas demo w v low expectations after a sub optimal Divas demo
What I didn't expect was a room fully pressurised by the unique vertical density wall of bass down to 21Hz, all by 80 W 211s
But the room was yr standard 18x11x8
My room is 50x18x9 (ht more like an average 7 due to descending eaves)
Do I absolutely have to allow for the 50% of room volume behind me when assessing demand, assuming like Mike I sit at mid pt of depth?
Is the "unused" 50% listening space behind me as critical on spkr-amps demand as the zone I'm listening in?
 

Mike Lavigne

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So what do you say if I tell you my current Zus wk great down to 50Hz w my 70W 211s, w bass <50Hz covered by 300W Class D Hypex in built subs/Lundahls transformers?

makes perfect sense. the Zu's are quite efficient (almost 100db? don't know exactly how efficient?) and 300 watts on the subs should be plenty.

OTOH (and don't over-react) unless you had more power up and down the FR you never know what greater 'current leverage' might be able to do for you in terms of ease and authority for the music. these are almost always compromises to every system. but in a room your size where the potential for great dynamics are larger than more moderate sized rooms you simply have a higher ceiling for these things so they need to be considered. I'm not trying to send you over the edge into defib over approach changes. but large spaces do open up a whole new world.
 

Mike Lavigne

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Lloyd and Mike
I went into this Duettas demo w v low expectations after a sub optimal Divas demo
What I didn't expect was a room fully pressurised by the unique vertical density wall of bass down to 21Hz, all by 80 W 211s
But the room was yr standard 18x11x8
My room is 50x18x9 (ht more like an average 7 due to descending eaves)
Do I absolutely have to allow for the 50% of room volume behind me when assessing demand, assuming like Mike I sit at mid pt of depth?
Is the "unused" 50% listening space behind me as critical on spkr-amps demand as the zone I'm listening in?

in the lower frequencies the larger, longer space is a big deal. not so much for mids and highs (or rather those issues can be easily dealt with if they are an issue) as those are mostly reflective. although with the slanted ceilings people sitting back a ways could get some severe reflective things happening. but mid room likely controllable and not too much of an issue.
 

JackD201

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Both. However to simplify things a bit, generally, room volume when it comes to output below the turnover/transition frequency Marc, square meterage and geometry for above that. I like to use the radio analogy. Higher frequencies are line of sight like FM, lower frequencies with their long wavelengths bounce off the atmosphere (ceiling).

More volume, more output. Output the "power to weight" ratio of the transducers and their amplification. IME I always prefer bigger speakers (more mid bass potential) as opposed to basically force feeding a smaller speaker with more power. It's a question of sense of ease. The less strain on the midrange to try and keep up with efforts to energize the room the better.

As for apogees specifically I can't make too clear of a prediction. Dipole bass is different from conventional bass alignments especially above 50 to 60 Hz. They may reinforce and cancel very differently given certain placements within the environment. Whereas cone speakers tend to end up or lock in in the same general locations, dipoles may end up feet and not inches from where your Zus are now. That's not a bad thing, just different. That was my experience with my Maggies.
 
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spiritofmusic

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Sure Mike
All views wanted here, esp from guys like you who have not only been there and done it, but also got the t-shirt LOL
There's nothing like expectation bias being turned on it's head 180
Or should I say, non expectation bias
I had zero confidence I was going to like the sound
30s in...
There was nothing lacking in this combination
But I'm aware the room was a snug cosy fit
 

853guy

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Aug 14, 2013
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Please make allowances for me if these are stupid qs LOL
When assessing room size and whether things are practical for a particular spkr, spkrs-amps synergy, which of the following list are true or relevant?
Do we consider flr area or volume?
Ie if one lives in a double or triple ht space, or alt in a loft space w descending eaves, do we still only consider the plan area as you would do in a regulation ht 8' room, or does the extra volume in 12'-20' ht absolutely have relevance acoustically, and esp in assessing physical demands on spkrs-amps?
Additionally if one lives in a very big space, and in effect sits in the mid pt of the space and the listening zone is purely the front half of the room, is the rear of the room relevant (other than rear reflections/ambience)?
Ie if one's space is twice the size of another, one sits in the middle of the room, v the other space where you sit right against the back wall, do the spkrs-amps recognise this? Or are they energising the whole space and sound will be v different?
I ask all this because I've just listened to Apogees mate brilliantly w 80W 211s in a standard 18x11x8 room
But my space is a more expansive 18x50x9 loft, where I'll be sitting right at the intersection mid pt of the front and rear of the room
And I'm trying to wk out if 211s and Apogees can replicate their feat here that they did in the 2-3x smaller space

Hey Spirit,

My guess, based on absolutely zero experience of living with Apogees is this...

A dipole loads a room very differently than a monopole, right? You're going to be exciting less room modes than your Zus, so you have some space to play around with the Apogees in a way you don't with your current speakers. It also gives you greater freedom in where you sit relative to both the speaker and how far away you are from the rear wall behind you.

To me, that means that you can possibly create a more direct and immersive experience via the Apogees in your room because of their figure-of-8 radiation pattern, in which bass peaks and nulls can be tamed by careful placement (provided you do not do any sort of front-wall* absorption - only diffusion), while still giving you wriggle room in terms of listener placement for maximum impact. Given the relative levels of coherence in the frequency and time/phase domain from the panel, you may find your current amplifiers more than able to provide decent levels of low frequency amplitude that isn't robbed by the room nor your seated position.

Am I saying Apogees and your NATs is gonna give you everything you want? Or that an amplifier with greater current delivery wouldn't be "better"? No, this is all guessing. I'm saying it's not out of the question, in the way it would be with a conventional box speaker in which the radiation pattern and nulls/peaks are more problematic.

Be well,

853guy

Edit: *I.e., the wall behind the speakers.
 

microstrip

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Remember that the sensitivity specification of a speaker XX dB/W/1m can be a very misleading figure. It is only valid to point like speakers and is measured in anechoic conditions. In real life what you get in your room cab be quite different from estimations made with this figure, even using the usual correction parameters for line or planar speakers. Rooms can have gain or be absorptive - either objectively or subjectively.

And yes, the best acoustic treatment is a cluttered room, particularly if you stick everything close to corners and edges ... IMHO a well furnished and decorated room is subjectively preferable to an empty, mainly wall and ceiling treated room. Surely YMMV.
 

spiritofmusic

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Oh, I have a ton of flexibility w the Duetta
At 8' seperation they're 2.5' from side walls, outer top edge 2' from descending eaves
I can place them 5' to 9' from front wall
I can sit from 1" to 45' from them
So, I'll be going from my Zus w full range drivers and Radian Supertweeters 40Hz-20kHz+ 101dB eff all driven by 70W parallel 211s, w deep bass Class D 300W to <20Hz which absolutely lock into my room
Ked's advice is the logical one
If I love 'em and feel I can't live w'out 'em, buy 'em
And make my deal w the Devil and go SS
And in time forget the true love that is SETs
 

FrantzM

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Remember that the sensitivity specification of a speaker XX dB/W/1m can be a very misleading figure. It is only valid to point like speakers and is measured in anechoic conditions. In real life what you get in your room cab be quite different from estimations made with this figure, even using the usual correction parameters for line or planar speakers. Rooms can have gain or be absorptive - either objectively or subjectively.

And yes, the best acoustic treatment is a cluttered room, particularly if you stick everything close to corners and edges ... IMHO a well furnished and decorated room is subjectively preferable to an empty, mainly wall and ceiling treated room. Surely YMMV.

+1 on that.

Lost in the discussion is the construction of the room... An example. Supposing a room made with drywall/sheetrock. There is a cavity between the actual shell of the room, In that case let's suppose concrete and the sheetrock. The depth of those cavities and volume can act as an bass trap ... especially when there is fiberglass insulation in between. Such room distribution of modes will be quite different from what calculators will give you. These are mostly based on the dimensions of the room and the assumption that the walls are rigid... We could go in the particular but that it to give you an idea. IOW exact same dimensions of rooms but different construction shall lead to vastly different bass performance.
Your best bet is to measure , anathema to some. You measure then correct with ears but measure first. that gives you repeatable starting position. However great we think our hearing is, it is not accurate. If bass is inadequate a subwoofer ( another anathema to many) may help, the best help will be achieved with DSP + sub(s) ... Now I have lost all sanctity :p
 

bonzo75

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In my far more limited experience, this is very similar to what i just PM'd to Spirit privately. i agree about the pressurization of his room and the Apogees he is looking at. i would have guessed that, if it is going to happen at all...high quality, high levels of current will be required. Or he can consider the larger and legendary Apogee Full Ranges, though i recall someone suggest that the width of his room might require careful consideration for this...cannot exactly recall.

This part of reproduction is not something that is on everyone's priority list, but eventually as one starts to check off all the other 'must have's in audio...eventually scale and effortlessness in filling a room can [for some people] become one of those must have goals. In Spirit's room...why not feel like you've got a small concert going on?

In his room if he had level ceilings, FRs would have been ideal. Because his ceilings are sloping, he can only accommodate Duettas. They will lose out on scale to a bigger speaker, but the only bigger (scalier, bassier) speaker he can accommodate by placing wider and in a bigger triangle is a big horn (big for a horn, yet height wise smaller than a FR or an Alexandria), but with loads of bass output. But then trios which qualify are too high a price. There are a couple of bespoke/customized ones made in the EU, but they will also be too heavy to go up his spiral staircase. In that kind of space, I would have definitely gone horn to get that bigger scale.

But I think if he is ok to sit more nearfield, in a 7 ft width and adjust accordingly, the Apogees are additionally better rounded for playing the rock music he likes and easier to get up the staircase. IMO the amplifier problem is a red herring and can be easily solved. Good to worry about till it's solved. It's not like an audiophile has stopped auditioning ancillary equipment after buying a speaker. Amp merry go rounds are required to keep us in the hobby
 

Rodney Gold

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The bigger the room , the more like you are sitting outside listening to your stereo .. and as ideal as that may seem , its actually not sonically pleasing .. a quasi anechoic chamber if you will..
Big rooms are expensive and difficult to treat..lots of stuff needed compared to a smaller room to treat the echos , the bass , the diffusion , the absorption all require multiple devices.
I often wish for a smaller but higher room myself.. Im needing 12 full height 20" tube traps for a 500sq ft room.. and thats not all I need ...it's merely a start.
You want to deal with small room acoustics and not concert hall stuff
But anyway , you have the space .. find a spot (and there will be one) where it all sounds good and work your treatments from there..maybe even subdividing the space?

it's an interesting journey and best of all , you generally get plainly audible and better results as you go along...will keep you occupied for the next year or 2 ....
 

spiritofmusic

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Guys, the more I think about it, the more this "dead" space behind me is counterproductive to getting the magic out of SETs and Apogees
Handy to be thinking about this all while reading everyone's comments and knocking back a couple of pints of Guiness
My idea?
Seperate my space w a sound reinforced dividing wall, to create two rooms, AV cinema room and new 18x22-25x9 audio space
This will result in less volume demands on NATs/Duettas pairing, and enable me to switch my Zus to cinema duties
My hope would be this new space would be big enough to breathe yet compact enough not to overwhelm 70W 211s on ribbons
My aim is to have my cake and jolly well eat it !
 

Rodney Gold

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18x22-25x9
Same size as my room..
 

spiritofmusic

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At yes, but alas no Sahara shade Giya G1 Spirits
I thought I'd be good enough to let you have those
 

KlausR.

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spiritofmusic said:
Please make allowances for me if these are stupid qs LOL
When assessing room size and whether things are practical for a particular spkr, spkrs-amps synergy, which of the following list are true or relevant?
Do we consider flr area or volume?

Here’s what J. Gordon Holt said about the listening room:
The final link in the high-fidelity sausage is the listening room. The room itself does not listen, but is called a listening room because it contains a listener.

The sound field at the listening position is composed of direct sound and early reflections, the reverberation part is of negligible effect, says Floyd Toole in his 2006 AES paper and in his book.

The direct sound doesn’t change with room size or volume provided the listening distance is the same. What does change is the level of the reflections, so both floor area and volume count. For a given stereo triangle, the greater the floor area the further do reflections in the horizontal plane travel, the greater the volume for a given floor area the further do reflections in the vertical plane travel.

I made some rough calculations of the level at listening position for three rooms of different size, stereo triangle identical in all three rooms, radiation pattern of loudspeakers not taken into account. Doubling the room size results in the level that is a bit lower compared to the smallest room. In the largest room (20 times the floor area and 30 times the volume of the smallest room) one needs about twice the amp power for obtaining the same level. For speakers that are rather directional the amp power has to be roughly doubled once more, hence 4 times of what is needed in the smallest room.

In rooms of different sizes the room mode pattern is different, in a loft with descending eaves things will get more complicated and difficult/impossible to predict.

If you sit against the rear wall in the smaller room and in the middle of the room in the larger room you are closer to the pressure maxima and closer to (some) pressure minima, respectively, so depending on how the room modes are excited that might make an audible difference. Sitting against the rear wall the reflection from that wall comes with very short delay, sitting in the middle of the room that reflection comes with greater delay. In how far this makes a perceptual difference, if at all, I wouldn’t know.

If in the smaller room the amp is already playing at its limit, a room of twice the size may be somewhat of a problem. Apart from that I’d say the amp won’t notice the difference.
 

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