New Music Room in UK south

Hey ! I've only just seen this thread having started my UK South based practice room / studio 4 years ago, then getting buried in that and numerous other things and then only just returning here last week to finish off a much overdue build thread. viewtopic.php?f=2&t=17952 Not only also being UK South Based (Glos) but we also have other similarities i.e. trying to build a UK compliant structure which can also become part of the house again should you decide to move on. But you look to have then taken things a lot further than myself - I just needed sound isolation and less focus on sound control but its good to see you going a lot more in depth than I did. Great to see the progress, all the very best. If there is anything I can help with just holler - on the basic / similar stuff that is as there are many on here far far more savvy on the techie stuff than I am :D - and good to see Stuart / Soundman is on the case for you. The devil is in the detail ! Cheers Roger

Thanks Roger, great to read through your thread, I learnt a lot from your build.

Mulling over speaker positions… One problem with the dimensions you have given me Stuart is that, assuming I make the main baffle as wide as possible (that is 120cm that the wood sheets come in) this means that the acoustic axis is very close to the centre of the baffle (on the horizontal plane). I don’t see there is a way round this because given the width of the speaker there is very little room on either side to play around with. So then I was thinking that it could be better with the speakers turned round to their ‘normal’ orientation (with the woofer on the inside). This is better in the respect that the speaker angle can be bigger (35 degrees rather than 28) and so the acoustic axis of the speakers are a bit further apart (even thought the speaker boxes themsleves are in virtually the same position just reversed). But this then means that the acoustic axis is at almost exactly 25% the width of the room which is not good. So then I went back to your dimensions as being best and just having to live with the acoustic axis being a bit too close to the centre of the baffle. Because the baffles will be heavy (18mm mdf + 18mm osb + 9mm ply) I am thinking that it won’t be too bad. Maybe most of the acoustic energy will be coming from the woofers anyway which are quite a bit more away from the centre of the baffle, I am imagining that they will be much more likely to set up resonances in the baffle than the mid range driver or tweeter anyway? On the vertical plane at least it is easy to put the speakers well off centre but how much space should I leave top and bottom, above and below the baffle front? I am thinking maybe around 60cm in between the bottom of the baffle and floor and the the same at between the top and ceiling. See diagram below I was imagining the ‘wings’ as large baffle like construction with the same big gap at top and bottom as on the actual soffits (so the sound waves can access the voluminous absorption behind) but then I saw some pics with slatted fronts. Would that be a better thing to do? Anyway here is my best plan for the angles of the wings and baffle geometry. Sorry I can’t manage sketchup. I need to start buildng soon so if anything jumps out as being bad please let me know. Many thanks. Cheers David ps - been working on doors and windows, a few photos coming soon I hope but it is too dark in there to take photos, the electrician is supposed to come and connect up the lights but he is very very tardy.

One problem with the dimensions you have given me Stuart is that, assuming I make the main baffle as wide as possible (that is 120cm that the wood sheets come in)

On the other hand, if you turn them sideways, then they are 240cm wide... :) There's also nothing wrong with putting two sheets next to each other! There are several good methods for joining sheets of wood, practically invisibly.

On the vertical plane at least it is easy to put the speakers well off centre but how much space should I leave top and bottom, above and below the baffle front?

Usually the bottom edge of the baffle itself ends up around the level of your desk surface, or maybe a bit lower.

I was imagining the ‘wings’ as large baffle like construction with the same big gap at top and bottom as on the actual soffits

Right.

but then I saw some pics with slatted fronts. Would that be a better thing to do?

It depends on what the room needs. I normally don't like doing tuned treatment at the front of the room, as I don't want any "coloration" of the direct sound. But for example in Studio 3 I did that. The wings are actually slot walls, tuned to some of the problematic frequencies. In fact, there are "slot door/walls", because there actually doors in those wings, that lead to storage space behind on one side, and a small machine room on the other side. Those "doors" are very thick, as they incorporate slot wall modules.

Sorry I can’t manage sketchup.

There are many very good, simple tutorials on YouTube about how to use SketchUp. At first it looks daunting, but it really isn't that hard, once you get the basic concepts. One key is to use "make component" each time you create geometry that belongs together as an object (such as the six faces of a stud), to prevent it getting attached to other stray bits of geometry. If you do that every time, then it becomes simple. - Stuart -

Many thanks for your reply Stuart. Aesthetic and finacial considerations aside, practically there is only about 10cm on the left hand side of the (right) baffle spare (until the midpoint of the room) and 10cm doesn’t really make too much of a difference (putting the acoustic axis just 7.6% off centre). I suppose on the right hand side the speaker baffle could continue behind the wings but that would result in the woofer actually becoming more central and not less. I am guessing that the reason to locate the speaker off centre in the baffle is too minimize resonances within the baffle and I am guessing that because the baffle is big and heavy these resonances are going to be at a lowish frequency. If that is so then they are going to be driven primarily by the woofer and not the tweeter/midrange. Normally the acoustic axis of a speaker would go through the woofer I suppose but with KH310’s mounted horizontally the the acoustic axis in quite a way from the woofer - maybe about 20cm. So if I extended the baffle on the right by 40cm (behind the wing to the side wall) that would make the woofer exactly central. If the woofer is the important factor even with the acoustic axis of the speaker exactly in the middle of the baffle (horizontally) the woofer is already 17% off centre! Anyway you can see I don’t have the foggiest which is the best solution. What kind of experiments have been done which show that centralising the speaker in the baffle actually does give bad results in the real world? Or maybe is it just theoretical reasoning?

A few photos as an update ... got some electricity in so I am not working in a dark cave anymore

I have finally managed to get around to doing a better baseline rew test for my control room, hope I got it right this time. I followed the instructions to the letter but still had a few issues with levels so I am not quite sure it has all worked properly. Also I don’t really know what to expect as the control room is completely without treatment so it sounds pretty horrible. One thing that has surprised me is how closely the graph bumps correspond to the previously calculated modes. It amazes me when something theoretical then corrresponds to real life. The mdat file can be found here… https://www.dropbox.com/s/76ruwqtvec8w6 ... .mdat?dl=0 and below are a few screenshots for easy reference. A few details on my test … Speaker settings - not exactly sure what to set the controls on the Neumann KH310’s to, so I tried -5db bass and left lowmid and treble on 0. Measurement mic was C414 in omni pointed up at 60 deg at the listening position (I marked the floor so I can put mic in the same place next time). I did calibrate the soundcard but not quite sure I managed to use the calibration properly, it was basically flat anyway (-0.5db at 20hz). Interface is motu ultralight mk3 The speakers were in their final positions in boxes but without the front baffles attached. Any advice on the results gratefully received.

I have finally managed to get around to doing a better baseline rew test for my control room, hope I got it right this time. I followed the instructions to the letter but still had a few issues with levels so I am not quite sure it has all worked properly.

The data looks fine.

Also I don’t really know what to expect as the control room is completely without treatment so it sounds pretty horrible.

And it looks equally horrible, in the graphs! Which is good, as your room's problems are clearly visible. At this stage, it is supposed to look horrible.

One thing that has surprised me is how closely the graph bumps correspond to the previously calculated modes. It amazes me when something theoretical then corrresponds to real life.

:thu: Yep! It's always nice when theory matches reality. That also gives you good confidence that the theoretical treatment will fix the real problems... :)

Speaker settings - not exactly sure what to set the controls on the Neumann KH310’s to, so I tried -5db bass and left lowmid and treble on 0.

You seem to be rolling off the bass a little too much, so I'd try a slightly lower setting. The others are fine, for now. We won't know too much about how the high end needs to go until you get a lot of the treatment into the room. It's mainly low treatment that you want right now, but that will have an effect on the highs, so keep your speaker tweaks in reserve until it's clear if you might need them.

Measurement mic was C414 in omni pointed up at 60 deg at the listening position

The 414 is fine for now, but it would be better to get a proper acoustic measurement mic for future tests. The 414 has a rather large body, and it can affect the measurements themselves.

(I marked the floor so I can put mic in the same place next time).

That's the X and Y location in the room, but you also need the Z location: height. All three need to be accurate.

I did calibrate the soundcard but not quite sure I managed to use the calibration properly,

It looks fine.

it was basically flat anyway (-0.5db at 20hz).

At this point in the process, the calibration is pretty much irrelevant, but as you get the room tuned closer and closer to your final goal, it becomes more important.

Any advice on the results gratefully received.

The procedure from here on is actually simple, in principle (but not so much, in practice!): Take a look at the graphs and see what the biggest problems are. Fix those, take another set of readings. Repeat. And carry on repeating until you run out of money, or time, or patience, or wall space for more treatment. Clearly, your biggest issues right now are modal issues at 43 Hz, 83 and 123 Hz, so deal with those first: Those are very long waves, so you need very large, deep bass traps. Figure out which room axis each is associated with, and put suitable treatment on the correct walls / corners. The treatment you apply for those will also have a nice effect on some of the other low-end issues, but you'll need to take care that it does not adversely effect the high end. You don't want a dead room! You want a balanced room. One other thing: The good news is that your left and right channels are fairly similar: so you should have a good stereo image. However, your left speaker is slightly louder than your right speaker: you need to turn down the left by about 1/2 a decibel. That's not easy to do at this point, with the room the way it is, so don't try yet. Wait until you have some of the treatment in place. - Stuart -

Thanks so much for your reply Stuart, it is good to know that I haven’t completely messed up the test.

Soundman2020 wrote:

Clearly, your biggest issues right now are modal issues at 43 Hz, 83 and 123 Hz, so deal with those first: Those are very long waves, so you need very large, deep bass traps. Figure out which room axis each is associated with, and put suitable treatment on the correct walls / corners. The treatment you apply for those will also have a nice effect on some of the other low-end issues, but you'll need to take care that it does not adversely effect the high end. You don't want a dead room! You want a balanced room.

I am sure I need some serious absorbtion on the rear wall and corners. I am wondering what is the best thing to do here. Some options I am considering are are … - —Rockwool - Just fill as much space as possible with this. I bought rather too much rwa45 rockwool and now have more left than I can probably use. I still have a few rolls of the fluffy loft insulation left so I could use that as well, but I was thinking I might use that behind the soffit wings and maybe underneath the speakers in the soffit bottoms, but I could also use some as part of the rear wall treatment if it would be better than the denser rockwool. I am confused becasue there is so much conflicting information about what depths and densities should be used. —— Or I could try and build some hangers for the rear wall. I am planning a few hangers as part of the soffits but don’t quite know what material to use as the core. I can’t seem to find Hermosote over here and cork of that size is very pricey. I was considering heay duty cardboard but at this point in my build I have a fair amount of left over materials that I am keen to use - plenty of 6mm ply, 12mm ply, 11mm osb, 18mm osb, hardboard etc so I am wondering if I can use any of these for the hanger cores? Maybe the 6mm ply would work ok? —— tuned traps . I have been discounting the idea of tuned traps as I have no faith that I could make them succesfully. I could try in an emergency situation but not too keen unless everything else fails. — I have discounted diffusion panels as probably my room is too small for those to help — heavy duty waveguides in the rear corners. Interesting idea but can’t find out much info on them. I have too much choice for my limited knowledge. I can see some options but lack the ability to choose between them! Any help gratefully received Here is a small sketch of the dimensions of the back wall …

I am sure I need some serious absorbtion on the rear wall and corners. I am wondering what is the best thing to do here.

I would suggest a combination of pure absorption right up against the wall, then acoustic hangers in front of that. I've had decent success with that. It's one of John's very effective concepts.

—— Or I could try and build some hangers for the rear wall.

:thu:

I am planning a few hangers as part of the soffits but don’t quite know what material to use as the core.

John recommends Homasote. It's a sft fiber-board product, that is commonly used to make office notice boards for pinning up notes with push-pins ("thumb tacks").

I was considering heay duty cardboard but at this point in my build I have a fair amount of left over materials that I am keen to use - plenty of 6mm ply, 12mm ply, 11mm osb, 18mm osb, hardboard etc so I am wondering if I can use any of these for the hanger cores?

I have heard of some people using that type of core, but it's a bit too dense for my liking. Lighter, less dense stuff is better.

I have been discounting the idea of tuned traps

Smart man! :thu: They are a lot harder to tune than the text books tell you about. If you work carefully, and make acoustic measurements along the way then they can work, yes, but I'm not a big fan for general home studios.

— I have discounted diffusion panels as probably my room is too small for those to help

What are the final interior dimensions of the inner-leaf? I'm sure you have that some place in your thread, but I'm lazy to go looking for it, and it would be good to get a final update. And some photos, too!

— heavy duty waveguides in the rear corners. Interesting idea but can’t find out much info on them.

Actually, it turns out that hangers act like wave-guides. That's part of the reason why they work so well. And they don't need to be tuned (although you could if you really wanted to). Just following John's basic advice on how to build them and place them, and they'll work fine.

Here is a small sketch of the dimensions of the back wall …

OK, but how about the rest of the room? All of the dimensions are important... :) - Stuart -

Thanks for your reply Stuart, very helpful as always.

Soundman2020 wrote:

What are the final interior dimensions of the inner-leaf? I'm sure you have that some place in your thread, but I'm lazy to go looking for it, and it would be good to get a final update. And some photos, too!

L - 410cm W - 320cm H - 280 cm (rough sketch and photos below).

Soundman2020 wrote:

John recommends Homasote. It's a sft fiber-board product, that is commonly used to make office notice boards for pinning up notes with push-pins ("thumb tacks").

Can’t find it anywhere in the uk. Cork is far too expensive.

Soundman2020 wrote:

I have heard of some people using that type of core, but it's a bit too dense for my liking. Lighter, less dense stuff is better.

I think I should probably use the cardboard then, which seems the only thing which is light enough.

Soundman2020 wrote:

Actually, it turns out that hangers act like wave-guides. That's part of the reason why they work so well. And they don't need to be tuned (although you could if you really wanted to).

I thought the idea of waveguides was that they were big and dense and so would reflect sound to the required place. I can’t see cardboard with a bit of rockwool reflecting many of the troublesome low frequencies. As long as they have a beneficial effect on the low frequencies then that is what counts I guess, all the theoretical stuff is well above my pay grade anyway.

Soundman2020 wrote:

Just following John's basic advice on how to build them and place them, and they'll work fine.

I am wondering whether it would be better to use the denser rwa45 or fluffy rockwool for the hangers? I noticed one description that said to use 2.5 cm of rockwool on each side glued on but I can’t see gluing the fluffy insulation to cardboard is going to work well. And the rwa45 I have is in 10cm batts - I can cut it but probably not neatly to 2.5cm. Would 4/5 cm on each side be ok-ish? Glued but with some gaffa tape reinforcement or maybe string? Having had a quick look at the space available I think I can get in about 3 or maybe 4 full length hangers on each side in the rear corners, about 240 x 45 cm, with at least 10cm of rockwool against the rear wall and ceiling and floor behind the hangers. In addition maybe I can fit some smaller hangers against the top of the rear wall - I think there is space for 5 or 6 at around 60 x 35 cm. Do you think that is looking in the right ballpark? cheers David

I've been moving the rock wool in, lots of it. Here are a few update photos ... More REW tests coming soon. cheers David

So finally I have got round to doing some more REW testing in the control room now that (hopefully) all the absorption is in. I will post all the results below, I am not really sure how to evaluate them but they don’t look too bad - frequecy response is flat within +-6dB without any smoothing (in the low frequencies) and there is not that much low boomy decay going on. I guess I can fine tune a bit but the most important thing right now is to get the speaker settings correct before I finally screw all of the soffitts and wings together. I put a single layer of soffit front on just to run the tests (but not the wings yet). These tests were done with my KH310a’s set with just a bass cut of 2.5dB but I am wondering if I should set the low mid cut to -1.5db as well to tackle the boost in the graph between 150 and 325hz. I can’t seem to find any mention of at what frequecies the controls act at and it is a very large hassle to take down the soffits and deconst the speaker boxes everytime I want to change a setting so it is pretty important to make the final decisions right now. The other setting I have no idea about is the input/output level settings on the speakers. At the moment I set the output level switch to 100dB spl and the input gain control to 0 and have no idea if this is suitable or not. It sounds good to me but as I haven’t got a desk in yet it is problematic to know if it will work suitably when I do. I can’t work out how to send a reference level from my laptop/motu interface either. The REW levels seem all messed up to me, it keeps telling me that my level is far too low but the results seem to look ok, to me at least. I have to turn the laptop output level down to around half in the systems preferences in order to get the sound at 80dB (C) but have no idea what actual level that is. I am not working in broadcast or film so I guess it is not really critical as long as I get plenty of volume from the speakers and don’t clip when sending full level. There are 3 tests I did ... 1 - without the soffit front mdat 1 https://www.dropbox.com/s/11grca7u8zq0m ... .mdat?dl=0 2 - with the first layer of soffit front mdat 2 https://www.dropbox.com/s/3b9vssgqr0fh3 ... .mdat?dl=0 3 - and with an additional couple of absorption panels on the floor at reflection point between speaker and mic. mdat 3 https://www.dropbox.com/s/f4nx895xy85ut ... .mdat?dl=0 There are few graphs below from mdat 3 just to give a quick idea In other news I finally got the live room up and running and had my gand piano moved in yesterday. Still a lot of organising and soldering to do. Photos should come in the next week. Any help gratefully received. cheers David

Or alternative frequency response view ... The room seems a little dry but maybe there will be more reflections when I have wings and some other hard surfaces cheers david

a couple of photos of the live room. great to finally have some instruments and musicians in there cheers david

Hi I don’t know if Stuart or anyone else is reading all my posts, it is rather quiet here. Anyway I will ramble on in the hope that somebody can help out… So I finally screwed up the soffits and attached the heavy duty side wings and ran yet another rew test. Comparing the previous test (with just the first layer of baffle attached) with this most recent one (with full baffles and side wings) I was disturbed to see the results seem to have got worse. Maybe I am misunderstanding the results, I am very far from being an expert, but at this point I am tempted to just take the side wings off and chuck them away. I thought I would share the results here in case anyone had any opinion about this. As a comparison here is the previous mdat (with just the first layer of baffle attached)… https://www.dropbox.com/s/7a2hik8ltk7nz ... .mdat?dl=0 and here is the new mdat (with full baffles and side wings)… https://www.dropbox.com/s/ltv21wrhlmd3x ... .mdat?dl=0 My areas of concern are … 400hz - a worrying dip around 6db worse when I add the wings. Not that much of a difference at other frequencies except … …between 4k and 7k there is a huge 20dB dip which is completely absent in the rew taken before I added the side wings. Also this is not apparent on the individual L and R speaker readings which look ok in this range even wth the side wings. I don’t even know if I should be worried by this such is my level of incompetence. Waterfalls - I was hoping that the addition of the side wings would result in the room being a little less dry but the addition of several m2 of hard reflective surfaces does not seem to have made an appreciable difference. I suppose it would probably be better with some more life in the room but I can’t see how to improve this. In a larger room maybe slats would help but already my side walls are almost entirely reflective being mainly made up with the side wings, windows and doors. I am not sure putting slats on the rear wall or ceiling is a good idea. Anyway there it is. Quick reference graphs are below. Any advice greatfully received. Cheers David

I don’t know if Stuart or anyone else is reading all my posts, it is rather quiet here.

Still here! Still following! Still interested! Just a bit overwhelmed with workload right now...

I thought I would share the results here in case anyone had any opinion about this.

Great! I just downloaded the MDAT files, and I have to say that your room response is looking pretty good! However, there's one thing that worries me: one set of measurements is called "withbaff and eq". I'm not sure what that means, but if you had some type of equalization applied when you took those measurements, then they are no use. If that's the case, then you'll have to go back and do those readings again. EQ will have totally screwed up any possibility of seeing the REAL response of the room, so you can throw out any measurements you did with EQ, go back to the room situation at that time, and repeat the measurements with totally flat response across the entire signal chain. The reason is quite simple: using EQ disguises the true response, so you don not know what the remaining problems in the room are! It's like going to see the doctor for your fever, and giving him all your temperature readings made AFTER you already took analgesics and anti-inflammation medication! Those readings are totally useless and invalid, since the medication is disguising the fever... So the doc won't be able to diagnose anything about your illness, since you covered up and hid the symptoms with the medication. Yes, EQ, can be used to smooth over some final remaining issues in the room, but only under certain circumstances, and only AFTER the room has been fully completed, and fully treated, and fully tuned acoustically, until the necessary conditions are met. Using EQ before you even have your treatment in is pointless, since it grossly distorts the true situation.

400hz - a worrying dip around 6db worse when I add the wings

Are you certain that you designed the wings to be at the correct angle? Did you ray-trace that, to make sure? Are you SURE you did the ray-tracing correctly? From my point if view, the angle of your wings does not seem large enough.... It's hard to tell just from a photo, but that's what it looks like to me. There are new reflections appearing in the L and R IR measurements, that seem to be at about the right delay (location) for a bounce from the wings...

…between 4k and 7k there is a huge 20dB dip which is completely absent in the rew taken before I added the side wings. Also this is not apparent on the individual L and R speaker readings which look ok in this range even wth the side wings. I don’t even know if I should be worried by this such is my level of incompetence.

Nothing to worry about: that dip is not actually there in reality. It's likely due to just having the mic perfectly located on the center line of the room. You would never actually hear that, since you do not have just one single ear located in the exact middle of your head! Rather, you have two separate ears, located a few inches off to the side of where the mic was for that reading, and the response that each ear will hear is far closer to the individual L and R readings, than it is to the combined LR reading. The LR reading is mostly to check the low end with both speakers on, not the highs. The low end can often suffer from interference between the two speakers, which is why it needs to be checked, as you really will hear that (low frequency = long wavelengths = valid at the mic position). So don't be concerned at all about what you see about about 500 Hz or so, in the combined LR readings.

I was hoping that the addition of the side wings would result in the room being a little less dry

It is too dry, certainly. The overall decay times are all around 110 ms, which is way too low for that room. It should be more like 230 ms. for that sized room.

the addition of several m2 of hard reflective surfaces does not seem to have made an appreciable difference.

I disagree! There's a clear increase of about 10 to 15 ms, across the board. It's a bit more in the highs than the lows, but it's there all over.

I suppose it would probably be better with some more life in the room

Definitely!

I am not sure putting slats on the rear wall or ceiling is a good idea.

Not on the ceiling, probably, but there's nothing wrong with doing it on the rear walls ... provided that it is done intelligently and correctly: correct sized slats, correct placement, and correct coverage area. It's an easy way of increasing decay rates that are too low. You wont get a huge increase from making the front o the sides of the room more reflective, if the rear is dead! The front and sides of the room should be designed to send all the reflections to the rear of the room, and if the rear is pure absorption, that energy will never get back to your ears: hence, the room remains "dead". You do need "stuff" on the rear to send some of that energy back towards you, but in a carefully controlled manner... If you want to test this to see what I'm taking about, just put a couple of full sheers of plywood standing up vertically, leaning against the back wall, and do a REW test like that. I think you'll see the difference! :) But before you do that, remove all EQ from your signal chain and repeat the above tests. And also double-check the angles of your wings: I strongly suspect that they are not angled correctly. - Stuart -

Soundman2020 wrote:

Great! I just downloaded the MDAT files, and I have to say that your room response is looking pretty good!

That is very good to hear Stuart.

Soundman2020 wrote:

However, there's one thing that worries me: one set of measurements is called "withbaff and eq". I'm not sure what that means, but if you had some type of equalization applied when you took those measurements, then they are no use. If that's the case, then you'll have to go back and do those readings again. EQ will have totally screwed up any possibility of seeing the REAL response of the room, so you can throw out any measurements you did with EQ, go back to the room situation at that time, and repeat the measurements with totally flat response across the entire signal chain.

My purpose in doing a ‘with eq’ test was to try to work out what were the optumum speaker settings before burying the speakers in the baffles. Neumann recommend settings for various placements and so I thought I should try them out before the controls became unavailable - there is not much point in discovering that there is too much bass at the point where it then becomes impossible to turn it down. The graph should really then be labelled ‘with speaker compensation’ but it is just eq really isn’t it. Now the speakers are buried in the baffles and it would be hours of effort to get to them so I hope I set it for the optimum performance.

Soundman2020 wrote:

But before you do that, remove all EQ from your signal chain and repeat the above tests.

Would you advise to do all the acoustic testing without using any speaker compensation?

Soundman2020 wrote:

Are you certain that you designed the wings to be at the correct angle? Did you ray-trace that, to make sure? Are you SURE you did the ray-tracing correctly? From my point if view, the angle of your wings does not seem large enough....

Well I am not quite certain. I did it to the best of my ability and without any instructions which is not quite the same thing! The constraints of the room made it hard to get enough angle but I thought it looked ok on the ray tracing. (diagram with wing angle and ray tracing at the end of this post) It is possible I messed up slightly the actual building of them, I am far from being a good craftsman, but it should be accurate to about a cm. Anyway my options at this point are — - leave it how it is and live with it - replace side wings with fabric - make adjustments to side wings Having looked at the ray tracing and design one more time I don’t know if there is much adjustment i can do. I may be able to bring the inside edge of the wings forward an inch (maybe 2) which would result in a steeper angle but that would leave a gap between the side wing and the front baffle, don’t know if that is bad or not?

Soundman2020 wrote:

It is too dry, certainly. The overall decay times are all around 110 ms, which is way too low for that room. It should be more like 230 ms. for that sized room.

Yes I thought so, I just can't see how I can begin to extend the decay to 230ms.

Soundman2020 wrote:

You do need "stuff" on the rear to send some of that energy back towards you, but in a carefully controlled manner...

That is one adjustment I was half expecting. But before I add “stuff” I would like to work out what “stuff” that should be and where to add it effectively. I can see that higher frequency reflections that are directed to somewhere other than the listening position might be a good idea to increase the general liveliness so I suppose I should aim for that. I haven’t worked in the room for that much time yet but so far I don’t find the dryness too bad, maybe because there are massive big baffles right infront of me that reflect all the sound I make directly back at me. If can improve things by adding a some slats I will definitely give that a try. I am guessing that I should use slats of differing widths across the sides of the back wall with the spacing between them varied. Is that approximately correct? I have looked around for info on slat size and spacing but there seems to be lots of different recommendations out there. As a rough guess I am thinking 3 sizes of slats between about 3cm and 10cm wide (whatever the wood shop has at the same thickness) spaced apart with gaps of around 1-3cm, placed in a pseudo-random order? Any further tips on this Stuart before I do it wrong as usual? diagram of front baffle/wing angle with faint ray traces of limiting angles below … also a rough sketch of dimensions of rear wall area - there are hangers to the L and R of the sofa and the dotted line indicates the fabric covering. Behind the sofa is 20cm of rockwool and some smaller hangers above …