More room choices than I know what to do with!

[tony22]

I decided to break this out from the tail end of my ‘dedicated outlets’ thread, as I’d like to give it more exposure for group thoughts and input.

On other threads I’ve talked about my new house and my desire to finally create a dedicated sound room. My initial thought was to use an existing 14x16 room whose side and front (speaker) walls are all exterior walls of the house, which is concrete block. The room interior is otherwise unexciting, rather standard. I liked that the room was all by itself, away from the bedrooms, was finally not oddly shaped compared to rooms I’ve used in past homes, and was “good enough” in size that it would be usable (if not perfect) for my system.

So I started thinking about ways to get things better. My first option was to knock out the back wall of this room, which would result in the room size increasing to 14x21, approximately. This would give my Endeavor SE’s more space, and make the room less “square”, both of which seemed better to me - at the expense of taking out a bathroom!

Then I started looking at the other side of the house. I could take down one interior wall between two rooms and get a 14x23 space, and unlike the other option I could do it without having to remove a bathroom. However, in this case only the right speaker wall would be an exterior wall. The front wall and the left speaker wall would be interior walls. Additionally, the front (speaker) wall would not be orthogonal. It would have a right angle on the right side, where the right speaker would go, but behind the left speaker the wall would be angled.

The angle would “push” the corner of the wall behind the left speaker in by about 3 feet. It is a part of the house that cannot be changed. The width of this angled wall would be on the order of 5 feet. It would cause the left speaker ambiance to fire back into an angled space, which is not the same shape as for the right speaker. In order for the sides of both speakers to “see” the full 14’ width of the room, I’d have to pull them out about 3-1/2 feet from the front wall.

So here is my question. Is it better to have a symmetrical front room shape behind the speakers with the side and front walls all “the same” (exterior), but be in a smaller room (let's assume 14x16), or would it be better to be in a larger space (14x23) but have to deal with an asymmetrical front wall - and a mix of interior and exterior walls?

Here are the acoustic assessments done using the tool on Bob Gold’s site. The first is the 14x16 originally planned room. The second is if I were to remove a bathroom and make that 14x21, and the last is if I go with this last space option. But the Gold’s curves do not account for that slanted space that would be behind the left speaker.

 

[tony22]

Hey, there are some pretty knowledgeable folks here! This one must have something that would prompt some input!

 

[spiritofmusic]

My friend, I'll add my 2 cents. Purely anecdotal, my hunch.
I used to run my Zus in a 27'x22' room, one 2' from R side wall LP shelves, the other effectively 13' from L wall bookshelves.
I truly believe this was a major contributor to awful bass/room interaction.
Had I stayed in that room, I'd have built another LP shelves unit to situate 2' from R spkr (shelves effectively a mid width room divider).
Fate conspired to put my system in an all together more conducive space, everything symmetrical, side walls 4' from each spkr.
And this is a big part of my system and SQ rebirth.
My advice...stick to the bigger room, and install that symmetrical boundaries idea.

 

[sbnx]

Bigger space is almost always better. with a length of 16' the fundamental mode will be 35Hz whereas 23 feet it will be 25 Hz. The lower this mode the better as it takes very, very little energy to excite it. The additional length will also enable you to pull your speakers out further from the front wall.

 

[tony22]

@spiritofmusic and @sbnx , here’s some additional info.

I take your note about the asymmetrical front wall being a problem, @spiritofmusic. I was figuring that would have to get handled somehow. So I’m attaching three scratchy drawings. The first is my attempt to show what the space would look like, proportionately, showing the left wall slant at its proportional length. The second shows what the front wall “flat” length would be if I created a matching “compensating wall” on the right side. You can see it really shortens the length of the front wall. The last drawing shows the approximate starting point locations (the small x’s) for my E SE’s, using Leif’s basic starting locations.

I’m a little worried about the extreme shortening of that front wall once a matching slant is put in. It would suggest having to pull the speakers much further out into the room, to clear the slanted walls, but then - at least according to what I’ve learned so far about my speakers - they’d be too far from the front wall for their ideal positioning.

 

[spiritofmusic]

But Tony, unaltered, you would still have one slanted angle necessitating a compromise on at least one spkr, the left one. That one will still need to be brought forwards. And so with both spkrs needing to be equidistant, you can balance things up building a new false slant.

Or am I missing something?

 

[Mark Seaton]

The symmetry of the small room would be welcome for imaging, but I'd lean away from that given the super rigid structure and what it might take to get the bass right while also requiring you to take out a bathroom to make it deeper.

It's a rare thing for the bigger room to not be desirable, especially vs only 16' depth. I would go with the longer room and match the front corner shape. I would also suggest you might want to beef up construction on the interior walls to reduce the difference at low frequencies. If you have the ability to beef up the wall surface on the far side of the room that would better match the exterior walls.. Considering your front speakers have a rear firing ambience driver, hard wall symmetry should be a top priority. A lossy rear wall is almost never a problem in a listening room.

Had you considered flipping the room so the angled corners are behind you rather than in front?

 

[tony22]

But Tony, unaltered, you would still have one slanted angle necessitating a compromise on at least one spkr, the left one. That one will still need to be brought forwards. And so with both spkrs needing to be equidistant, you can balance things up building a new false slant.

Or am I missing something?

Nope. You are right on target. My only fear with this is pulling the Endeavor SE’s too far away from the front wall and thus compromising its low end performance.

 

[tony22]

The symmetry of the small room would be welcome for imaging, but I'd lean away from that given the super rigid structure and what it might take to get the bass right while also requiring you to take out a bathroom to make it deeper.

It's a rare thing for the bigger room to not be desirable, especially vs only 16' depth. I would go with the longer room and match the front corner shape. I would also suggest you might want to beef up construction on the interior walls to reduce the difference at low frequencies. If you have the ability to beef up the wall surface on the far side of the room that would better match the exterior walls.. Considering your front speakers have a rear firing ambience driver, hard wall symmetry should be a top priority. A lossy rear wall is almost never a problem in a listening room.

Had you considered flipping the room so the angled corners are behind you rather than in front?

Thank you @Mark Seaton. Please elaborate on the rigid wall comment for the smaller room. Would that be more of an issue than the one exterior / one interior wall situation in my last choice?

How should I beef up the interior walls? Second sheet rock layer with Wall Damp in between?

Yes, but unfortunately the right corner of the room (when flipped) presents a depressed entryway to a rear bedroom and adjacent to it, the door to the guest bathroom. So the right speaker would be rear “ambiating” (I just made that up ) into a 3 sided “trap” made up of a wall and two doors at right angles to each other. Besides, the placement of the right speaker back there would likely be right in the path of walking to that bathroom.

 

[sbnx]

Tony, here is a drawing showing the first reflection points. I assumed you would have your speakers 2 feet from the wall leaving 10' between them and then you would be sitting 10' from the speaker forming an equilateral triangle. I highly doubt this position will produce the best sound in your room. You would be sitting at roughly the half way point where there will be a null and a large peak due to the second room mode. But If you choose this position then I would put a 4" trap behind the speaker on the slanted wall and a 4" trap on the side wall at the first reflection point. a 20" tube stack in the "corner" where the "slant" meets the front wall.

 

[tony22]

Tony, here is a drawing showing the first reflection points. I assumed you would have your speakers 2 feet from the wall leaving 10' between them and then you would be sitting 10' from the speaker forming an equilateral triangle. I highly doubt this position will produce the best sound in your room. You would be sitting at roughly the half way point where there will be a null and a large peak due to the second room mode. But If you choose this position then I would put a 4" trap behind the speaker on the slanted wall and a 4" trap on the side wall at the first reflection point. a 20" tube stack in the "corner" where the "slant" meets the front wall.

@sbnx, thank you for this! I don’t necessarily ascribe to the equilateral triangle arrangement, but since this is a new room for me that should be taken as a starting point. As I am an amateur when it comes to understanding these things, how far forward or back from the equilateral seating position would I have to move in order to mitigate the null and peak?

 

[sbnx]

I would suspect something like the pic below would be where I would start. The ear in the pic below is 4' from the rear wall. The speaker is 2' from the side wall and the distance to the speaker is 10'. (This is by no means fixed. You have to fish around to find the best spot) Your length modes are basically at 25Hz, 50Hz and 75Hz. Notice how three of the SBIR cancelations are at about those frequencies. You will still need to treat the first reflection at the sidewall with a 4" panel. Any time the sidewall reflection is less than about 6ms the sidewall reflection should be treated or it will mess up the stereo imaging and it just sounds bad (pingy). Also note that this just shows the first order reflections which are the biggest offenders. You will also have a bounce from the ceiling and floor.

Some larger bass traps would also help control the modal ringing. A soffit is a great way to do this without taking up floor space. (e.g. see the GIK soffit traps or you can build your own for cheap).

 

[tony22]

The ear in the pic below is 4' from the rear wall.

The ear in the pic? Is that the lighter circle on the left?

 

[sbnx]

Yes, the listening position is the circle on the left. The speaker is the other circle.

 

[tony22]

Really? Like this (the E SE is the speaker)? I’m concluding the drawing is showing only the left speaker? As you say, it looks to be about 10’ from the front wall. Wow. The E SE’s are “supposed” to be much closer to the front wall for optimal performance. Color me confused.

 

[sbnx]

Yes, you interpreted the drawing correctly. I only show one speaker as the room is symmetric an you would get the same effect from the right speaker. Finding the best place to sit and speaker location is best done empirically (using measurements is best but by ear is ok...just slower). My room is 28X22 and about 6 months ago I had a pair of smallish floor standers with a single 8" woofer set up with 13' to the front wall behind the speakers. The bass was outstanding. You could feel it thump your chest.

I don't mean any ill respect to speaker manufacturers but it is in their best interest to tell you that their speakers sound great up against the front wall as 95% of people don't have the space to pull them out into the room. My advice is approach this with an open mind and experiment. Try it with the speakers close to the front wall and then try it like the second position with the speakers 10' out into the room.

As an added benefit if you are going to put your gear between the speakers then when you pull them out then you don't get that acoustic interference like you would if the speakers were closer to the wall.

 

[sbnx]

One other note. It you find that the bottom octave is light then you can add a couple of subwoofers to fill that in. I am sure Mr. Seaton would be happy to sell you a pair and even help you get them set up.

 

[tony22]

One other note. It you find that the bottom octave is light then you can add a couple of subwoofers to fill that in. I am sure Mr. Seaton would be happy to sell you a pair and even help you get them set up.

I may get drummed out of WBF for this , but I’m generally not a fan of added subs. In my own experience listening to other enthusiasts’ systems I’ve generally found the music sounds better when the subs are turned off. I have heard a couple of systems where the musical continuity was unimpeded, so I guess I need to keep that possibility open.

 

[sbnx]

Nobody is going to drum you for your thoughts on subs. They are a split decision among audiophiles. Some like them and some don't. It is challenging to get them integrated properly. The higher up someone tries to run the subs the harder it gets to make them sound right. I think below about 45Hz it is not too hard to get them to sound right. They just add a little foundation and most importantly this sense of space and envelopment.

Either way, best of luck on your new room.

 

[LL21]

I am with SBNX. While I admit I have greater tolerance than others about discontinuity with sub integration than others...expressly because I do enjoy the subterranean depth they provide...i ALSO believe now in our system over the last 10 years, that having a big sub expressly cut off above 40hz is an amazing experience in terms of creating the true venue atmosphere all around you. It is particularly cool during jazz sessions when you are 'in the club'...you mute the sub...and then you are 'instantly' back in your own room. And then you unmute, and the sense of the venue is all around you again. Not sure how or why that works, but it really, really does.