Big Speaker in a small room?

[RayDunzl]

Holly shit, that's some performance!

Catch the whole movie sometime...

 

[Krunok]

Will do!

 

[andreasmaaan]

My two cents are that there is no problem in this case with the bigger speakers. It's true that speakers prefer some breathing room around them, but really this means breathing room around the acoustic centres of the drivers (or ports), not the boxes. There no particular need for space around the boxes themselves, assuming the drivers and ports have enough space.

In fact, keeping the acoustic centres of the drivers the same distances from the walls, a bigger cabinet is actually likely going to produce a smoother in-room response.

FWIW, I've always preferred large boxes and wide baffles. This is probably mostly because I like the better dynamics (i.e. lower distortion and higher max SPLs) of larger drivers, or it could be to to with the way baffle width and box size influence the frequency at which baffle step begins to occur, meaning that larger (especially wider) speakers will tend to have a power response that begins tilting downward lower in frequency. Another reason may be that larger speakers tend to better block the reflected wave off the front wall which in typical rooms tends to be quite strong, creating significant interference in the midrange with the direct sound from the speaker.

 

[Sal1950]

Let's ask some experts!

Please, GET A ROPE!

 

[pierre]

I have 5 focal trio6 and 2 subwoofers in a room of the same size. It works better with the 3 front speakers on the shortest side, calibration did make a lt of difference. I’am 1.6m from the 3 front speakers and that’s a bit short for this 3 ways. Overall amazing sound.

To be honest, I could have choose smaller ones and they would still work fine.

 

[oivavoi]

While I don’t have any scientific basis for saying this, my subjective impression is that there might indeed be some matching between room and speaker size. In a big room, small speakers often sound thin to me. While they can sound full in a small room. Similarly, I do sometimes have the impression that big speakers can overpower small rooms. There might be objective reasons for this impression, or it might just be my imagination.

 

[Wombat]

Doesn't it come down to loudspeaker output capability?

 

[Krunok]

While I don’t have any scientific basis for saying this, my subjective impression is that there might indeed be some matching between room and speaker size. In a big room, small speakers often sound thin to me. While they can sound full in a small room. Similarly, I do sometimes have the impression that big speakers can overpower small rooms. There might be objective reasons for this impression, or it might just be my imagination.

I actually tried it yesterday as I still have my Castle Richmonds so I put them on top of Harlechs and played some music I usually listen to. In my 40m2 room they did indeed sound thin, not only in bass. I tried to crank the volume and it helped to a certain degree, but it was still obvious they were trying hard, and not really succeeding, in filling the space with music.

 

[Krunok]

Doesn't it come down to loudspeaker output capability?

Capability, like to be able to play sufficiently loud? That was not my impression.. Sound level was ok but they sounded "hollow". Hard for me to describe it.. like they were struggling to do it, while at the same time, when I switched back to Harlechs I was impressed with the "ease" they were filling the same space and creating a wide soundstage, while Richmonds were not able to create soundstage in spite of producing sufficient dB level.

I hope my description makes some sense to you..

 

[KSTR]

Rooms that small are problematic pretty much regardless of speaker size, notably when you have solid rigid walls (concrete, bricks). The sparsely spaced low-order room modes shift up in frequency which will tend to give prominent peaks and nulls in the low and mid bass regions and room treatment with proper bass-traps etc is not very feasible, and costly anyway. Diffusors for the mid to high frequencies are much easier to make and a good thing because disturbing flutter echos will likely be very strong, too. Overdamping the highs also happens quickly in attempt to use mostly absorbers and this typically gives a boxy and lifeless sound when the mids and lows aren't damped equally as well.

An approach that has worked for me in the past is to use corner placement with small speakers, extending the baffle to the side walls, and the side walls and ceiling treated with diffusors to get rid of specular reflections, together with some mid/high freq damping. Back wall heavily damped but again also using some diffusors. Floor diffusors/absorbers are not easy to implement but help a lot.

This gives the largest soundstage albeit somewhat lacking in depth perception, and a very "dry" sound in general. Complement that with multiple subs placed strategically to even out the bass/response. DRC (via tools like "Acourate", REW etc) is pretty mandatory to get a acceptable frequency response at the listening position, and a bit of a larger, more live room sensation can be had when some artifical reverb / early reflections is added, especially when this is processed with some HRTF-tricks to make them perceived from way beyond the speakers both in the depth and width dimensions, sometimes height, too. Basically you try emulate a larger, well-designed virtual room whereas the influence of the real room is greatly attenuated.

 

[Wombat]

It does.
The small speaker is likely at a disadvantage compared with the larger one re LF output in a larger space(higher output required), tipping the tonal balance toward higher frequencies and thus being perceived as 'thin'.

 

[Krunok]

It does.
The small speaker is likely at a disadvantage compared with the larger one re LF output in a larger space(higher output required), tipping the tonal balance toward higher frequencies and thus being perceived as 'thin'.

Exactly. But besides the thin bass, which I extected, I was also surprised with their dissability to create soundstage in such relatively large space, which I didn't expect.

 

[oivavoi]

Capability, like to be able to play sufficiently loud? That was not my impression.. Sound level was ok but they sounded "hollow". Hard for me to describe it.. like they were struggling to do it, while at the same time, when I switched back to Harlechs I was impressed with the "ease" they were filling the same space and creating a wide soundstage, while Richmonds were not able to create soundstage in spite of producing sufficient dB level.

I hope my description makes some sense to you..

More or less aligns with my impressions as well. One thing is capability, obviously, and the ability to pressurize the room with bass. But it feels to me like there's more to it.

One possibility has to do with how deep in frequency the sound waves are projected mainly forwards from the drivers/baffle. Larger baffles and larger drivers throw more sound forwards. In a smaller room, this might not matter so much for the small speakers, because the reflections arrive so quickly that one nevertheless perceives the whole spectra of frequencies in a balanced manner. But in a larger room, where reflections arrive later, it might be that the direct sound from the small speaker feels thinner because the low midrange frequencies aren't thrown forward to the same degree, and the reflections don't arrive quickly enough to compensate for this.

As to why big speakers can overpower a small room - can it be related to relation between the roll-off of the speakers and the room gain? Will there be a more natural match between the room gain of a small room and the roll-off of small speakers?

 

[Krunok]

But in a larger room, where reflections arrive later, it might be that the direct sound from the small speaker feels thinner because the low midrange frequencies aren't thrown forward to the same degree, and the reflections don't arrive quickly enough to compensate for this.

These are my thoughts as well.

Let me add that my room is 5m (width) *8m (length) and my listening position is in the very middle of the room.

 

[Wombat]

Take the big speaker outdoors(very big room) and the same thing will be apparent with the big speaker - no reflections having an influence.

I think it is to do with maintaining sound pressure in space at the lower(less directional) frequencies.

 

[andreasmaaan]

In theory, below a room's modal (a.k.a. Schroeder) region, there's a pressure zone where wavelengths are so long in relation to the room that they don't even get a chance to bounce, so instead of adding and subtracting chaotically like they do in the modal region, they just build up steadily (pressurise). In reality though most apartments and houses don't have solid enough walls, doors, windows etc. for this effect to be very significant, i.e. the room is not structurally solid enough to continue to support rising pressure at lower frequencies. This would be the case with e.g. drywall constructions with thin doors, lots of windows, etc. If you have more solid walls though, and well-sealed doorways and other openings, pressurisation will be a more significant effect.

One reason smaller speakers might suit smaller rooms and larger speakers larger rooms is not anything directly related to the speaker's size, but rather the result of intentional design choices. Smaller hi-fi speakers are often designed with a small room in mind, which means that the bass response might not be anechoically flat, but instead be shelved down by a few dB in anticipation that the speaker will be placed nearer to room boundaries and/or be in a room where there's significant pressurisation. Another way this is often looked at is in terms of baffle step compensation; a speaker designed for a small room will not have full baffle step compensation in anticipation of extra "room gain".

So although not directly related to the speaker's size, this is one reason small speakers may not tend to suit large rooms and vice versa in practice.

If you EQ your system in the low frequencies, none of this should be of much concern.

 

[oivavoi]

In theory, below a room's modal (a.k.a. Schroeder) region, there's a pressure zone where wavelengths are so long in relation to the room that they don't even get a chance to bounce, so instead of adding and subtracting chaotically like they do in the modal region, they just build up steadily (pressurise). In reality though most apartments and houses don't have solid enough walls, doors, windows etc. for this effect to be very significant, i.e. the room is not structurally solid enough to continue to support rising pressure at lower frequencies. This would be the case with e.g. drywall constructions with thin doors, lots of windows, etc. If you have more solid walls though, and well-sealed doorways and other openings, pressurisation will be a more significant effect.

One reason smaller speakers might suit smaller rooms and larger speakers larger rooms is not anything directly related to the speaker's size, but rather the result of intentional design choices. Smaller hi-fi speakers are often designed with a small room in mind, which means that the bass response might not be anechoically flat, but instead be shelved down by a few dB in anticipation that the speaker will be placed nearer to room boundaries and/or be in a room where there's significant pressurisation. Another way this is often looked at is in terms of baffle step compensation; a speaker designed for a small room will not have full baffle step compensation in anticipation of extra "room gain".

So although not directly related to the speaker's size, this is one reason small speakers may not tend to suit large rooms and vice versa in practice.

If you EQ your system in the low frequencies, none of this should be of much concern.

Thanks, interesting!

Btw, this is slightly related but a bit OT perhaps: Is baffle step compensation really a settled thing - does everybody agree that it's needed? Has there been done any listening panel tests on this, for example?

I have had a hunch that baffle step compensation may actually make speakers sound bloated in the bass. The rationale is that one compensates for the loss of direct radiation of sound energy in the low midrange and the bass, as I understood it. But at least in a moderately sized room, these frequencies will still get radiated to the listener indirectly, through delayed reflections. If we increase the bass to compensate for the baffle loss, won't the total reflected sound energy in the room then be too bass heavy? I.e. - my question is whether we actually perceive the loss of bass in the direct sound in a small to medium sized room, or whether the room will naturally compensate for it, so that no baffle step compensation is actually needed.

 

[Soniclife]

In theory, below a room's modal (a.k.a. Schroeder) region, there's a pressure zone where wavelengths are so long in relation to the room that they don't even get a chance to bounce, so instead of adding and subtracting chaotically like they do in the modal region, they just build up steadily (pressurise). In reality though most apartments and houses don't have solid enough walls, doors, windows etc. for this effect to be very significant, i.e. the room is not structurally solid enough to continue to support rising pressure at lower frequencies. This would be the case with e.g. drywall constructions with thin doors, lots of windows, etc. If you have more solid walls though, and well-sealed doorways and other openings, pressurisation will be a more significant effect.

One reason smaller speakers might suit smaller rooms and larger speakers larger rooms is not anything directly related to the speaker's size, but rather the result of intentional design choices. Smaller hi-fi speakers are often designed with a small room in mind, which means that the bass response might not be anechoically flat, but instead be shelved down by a few dB in anticipation that the speaker will be placed nearer to room boundaries and/or be in a room where there's significant pressurisation. Another way this is often looked at is in terms of baffle step compensation; a speaker designed for a small room will not have full baffle step compensation in anticipation of extra "room gain".

So although not directly related to the speaker's size, this is one reason small speakers may not tend to suit large rooms and vice versa in practice.

If you EQ your system in the low frequencies, none of this should be of much concern.

I've always lived in places with sold walls and floors, and have found the bass to increase enormously with decreasing room size. I moved my system around three different rooms in an old flat and find found the middle size room was just right.

 

[andreasmaaan]

Thanks, interesting!

Btw, this is slightly related but a bit OT perhaps: Is baffle step compensation really a settled thing - does everybody agree that it's needed? Has there been done any listening panel tests on this, for example?

I have had a hunch that baffle step compensation may actually make speakers sound bloated in the bass. The rationale is that one compensates for the loss of direct radiation of sound energy in the low midrange and the bass, as I understood it. But at least in a moderately sized room, these frequencies will still get radiated to the listener indirectly, through delayed reflections. If we increase the bass to compensate for the baffle loss, won't the total reflected sound energy in the room then be too bass heavy? I.e. - my question is whether we actually perceive the loss of bass in the direct sound in a small to medium sized room, or whether the room will naturally compensate for it, so that no baffle step compensation is actually needed.

I don't know of any research that's studied this directly, but Harman's research into room curves dealt with it indirectly, in that it found that with flat on-axis measuring speakers listeners preferred a downward sloping in-room response. This must be partly the result of most flat-measuring speakers having wider radiation in the lower frequencies. It's not clear though AFAIK whether this is the room curve that listeners would have preferred had the speakers used been constant directivity right down to the bass (e.g. like Dutch&Dutch 8C, Danley Synergy series, etc.). AFAIK the Harman research used only speakers that had a downward sloping power response. I'm really hoping that Harman or someone else with the resources to do it properly does further research into this using a greater variety of different speakers, including true constant directivity designs and even perhaps omni, dipole or bipole.

Other relevant (also Harman) research into room correction DSP basically found that, below the Schroeder frequency, a smooth in-room response is more important than a smooth on-axis response, while the opposite is true above the Schroeder frequency. This would imply that baffle step compensation is necessary down to the Schroeder, but not below it (there are lots of opinions on this though and I don't think it's a settled question).

The way I see it, a lot of designers of home audio passive speaker have in fact basically been working on this principle for many years, by basing decisions about baffle step compensation on the size of the room the speaker is likely to be used in.

I think it's doubtful that trying to sacrifice the on-axis response to accommodate the room above the Schroeder frequency is a good idea (of course, the Schroeder frequency is a pretty slippery concept IRL and it's exact frequency in a given room can't be exactly defined).

My personal view is that room correction below the Schroeder frequency is important in small rooms, and that you may as well start with a speaker that measures flat on-axis and then correct from there. But where this is not possible or desired, the next best scenario would be a speaker that measured flat on-axis down to the Schroeder frequency and then - in very small rooms at least - gently slopes down a bit below there.

This makes passive closed box speakers a little more attractive in small rooms perhaps, or ported speakers that are tuned a little lower than textbook, giving a gentler, slower roll-off. It's also one reason why active monitors might not sound as good in small rooms without room correction: they tend to be (hopefully) ruler flat down to the their lowest frequency and then roll off at perhaps 48dB/octave below there.

 

[andreasmaaan]

Oh one other point... I think "baffle step compensation" is a concept that is kind of back-to-front, as you can maybe infer from my previous post. Flat on-axis response should be the goal, while "not using full baffle-step compensation" should really be seen not as something to do with baffle step, but rather as choosing to deliberately give the speaker a gentle low-frequency shelf in anticipation of the type of room it's going to be used in