Room set up advice

[HifiBruno]

First steps into a dedicated listening room. Any advice good, bad or indifferent welcomed. Dimensions are length 3.6m x W 3m hiegt to roof 2.4m. Rotel A10:49w amp, PSB Image speakers Akai turntable. Trying to use the 2/3 for set up not a lot of room so improvising on distances. Center of room alignment.. Thoughts on drapes behind speakers or should their be another option. Cheers.

[Nigel]

Bruno, big topic - but specifically the drapes behind the speakers are most probably only thick enough to absorb some high freqs only,  which would be the treble bouncing off the wall behind the camera, which is probably the more important wall for treble absorption.

Nothing I see except maybe the padded chair will do much for midrange or bass, which are harder to deal with.

 Is that carpet on the floor ? looks like it could be lino or something.....

Edited January 4, 2019 by Nigel

[GSO-ROB]

IMO get a quality subwoofer

also with such a box shaped room

build some bass traps where the curtains are and on the directly opposite wall

i.e.

 

[HifiBruno]

 igel yes it is carpet with underlay. Thought I may need heavier Drapes, will make some myself out of a heavier fabric. Have a leather covered two seater couch I use.

GSO-Rob, I can get a closed cell foam 50mm thick or any thickness I really I want. Any thoughts on how suitable this may be. My 35 year old turntable has started to give up the ghost so looking for a new modern option I think. Cheers 

Edited January 4, 2019 by HifiBruno

[GSO-ROB]

HiFiBruno

The 50mm is great 4 the opposite wall, is there a door there? If so cover it most internals are hollow core.

75mm panels behind the speakers would work great. You'll be able 2 listen louder without muddy bass roll off.

I've just replaced a Dual732Q auto & bought a manual Rega P2 with belt, cartridge & stub weight upgrade, cost all up $1k.

[almikel]

On 04/01/2019 at 6:19 PM, HifiBruno said:

I can get a closed cell foam 50mm thick or any thickness I really I want. Any thoughts on how suitable this may be

Closed cell foam is not the best product for acoustic treatment.

Normal insulation (poly or fiberglass) works better, and is available in increasing density from "fluffy" (ordinary batts) to densities of 48kg/m^3 and higher - for room treatment, 48kg/m^3 is typically the highest density usually used, but the lower densities (including "fluffy") can work well also.

 

To properly understand what treatment you need, and the effects of treatment you've applied, you really need an acoustic measurement rig - which is not that expensive, and will assist you in the process of applying acoustic treatment.

Do you have a laptop you could run Room EQ Wizard (REW) on?

REW is free, but to use it you'll need to buy a measurement microphone like this popular USB mike

https://www.minidsp.com/products/acoustic-measurement/umik-1

A decent microphone stand is also very useful - get one with a boom, so you can put the mike where you want to

Also a long USB cable (assuming you get a USB mike).

Starting your room setup/treatment journey with a measurement rig is a great step towards learning how to setup your speakers/subs and treat your dedicated room.

 

On 04/01/2019 at 3:39 PM, GSO-ROB said:

IMO get a quality subwoofer

^this

IMHO good "in room" sound starts with achieving good "in room" bass, which requires at least 1 decent sub.

You could delay the purchase of a measurement rig in favour of a decent sub.

 

Read Paul Spencer's "Bass Integration Guides" parts 1, 2 and 3...part one linked below

https://www.hifizine.com/2011/06/bass-integration-guide-part-1/

 

My approach to treating a room is to focus on the bass region first - get that right and IMHO you could stop there...

...but you'll need a measurement rig to know when you've "got the bass right".

 

Placing random absorption in a room can easily suck out all the treble and not manage bass - a poor outcome.

 

Get the bass right and you end up with tight/dry "in room" bass which makes you want to turn the bass up all the time.

 

cheers

Mike

[almikel]

On 04/01/2019 at 3:39 PM, GSO-ROB said:

also with such a box shaped room build some bass traps

if using poly or fiberglass insulation as an "absorption trap", the term "bass trap" is usually a misnomer.

Absorption traps need to be really large to be effective down into the bass range, and without a membrane in front to reflect higher frequencies (eg builders plastic) will happily absorb all frequencies above their effective lowest frequency of absorption.

For example here is 100mm of Polymax XHD (a popular room treatment product) mounted on a wall with no air gap

http://www.acousticmodelling.com/porous.php

I wouldn't regard this as a "bass" trap - it's really only effective above 400Hz or so, and a few sheets of this installed in the room could easily kill the top end without damping bass at all.

 

Absorption traps are "velocity" traps, and work best placed where the air velocity is highest - which is 1/4 of a wavelength away from a wall.

If you want to use absorption to trap say 200Hz, with the treatment having an air gap to place it in a high velocity zone

wavelength = 344/frequency so 1.72m, and 1/4 wavelength is 430mm

Use that same 100mm of Polymax XHD spaced 430mm from the wall has this response

Blue is on the wall, green has 430mm air gap - the green has much better bass performance - but you can see neither are "bass" traps - the green curve is still absorbing the top end and is just more effective lower in frequency - you can ignore the "ripples" - you won't get that response in a normal room - apply some "mental smoothing".

 

To get absorption to work well down to 100Hz or so

wavelength = 344/frequency so 3.44m, and 1/4 wavelength is 860mm air gap for maximum velocity!!

 

In practice, you don't need to target the "maximum" air velocity for absorption to be effective, but to work low the traps need to be big with reasonably large air gaps.

 

Given the space restrictions of most rooms, people end up placing absorption treatment "straddling" corners (ie "across" a corner with a triangular gap behind) when trying to manage "in room" bass - not many people have the space to have traps 400 - 1000mm inside the boundaries of the room.

 

IMHO for corner "straddling" traps to start to work into the "bass" range they should be a minimum of 600mm wide and 200mm deep "straddling" the corner, for the whole corner, eg for a vertical wall corner that means floor to ceiling.

Bass bounces throughout the room - so straddling any corner helps - wall/wall corners are the same as wall/floor corners are the same as ceiling/wall corners.

 

I recommend 600mm wide as the minimum width only because it uses 2400x1200 sheets of insulation efficiently - a wider trap straddling a corner will have (edit) a larger surface area and a larger air gap and hence work lower - absorption 1200mm wide and 200mm deep straddling a corner floor to ceiling will still be "sort of" working down at 100Hz - but not many people put up with this size of absorption trap in their room

 

Also by straddling corners, (ediy) most more of the wall space is left bare, so direct reflections are (edit) not less impacted, helping to maintain treble energy in the room (too much absorption can easily kill the top end).

 

Below 100Hz, if you still have remaining issues, absorption needs to be massive to be effective - this is where EQ works very well, and a few bands of EQ cut below 100Hz is usually all that is needed.

 

Hopefully by now your bass is under control, but you may have added sufficient absorption to have killed the top end.

To bring the top end back you can add a membrane or slats over the absorption to reflect the top end back into the room rather than absorbing it.

 

cheers

Mike

 

ps: once you've heard a room that has the bass under control (tight/dry bass with no overhang) - you can't go back.

You constantly want to turn the bass up

When you listen to other systems/rooms/cars with uncontrolled bass, you want to turn the bass down

Edited January 25, 2019 by almikel
clarification

[davewantsmoore]

On 23/01/2019 at 9:59 PM, almikel said:

Closed cell foam is not the best product for acoustic treatment.

Nor is 100mm thickness absorber on the wall going to do anything for the bass frequencies.

 

On 04/01/2019 at 12:55 PM, HifiBruno said:

First steps into a dedicated listening room.

Things like drapes, and your type of couch, etc....  don't really make a lot of difference, vs things like the location of the speakers and the listener.

 

Depending on what restrictions you have with seating arrangements, and how many listeners you are trying to get into the room, I would say the biggest initial setup thing is, don't make the mistake of sitting too far back in the room.    It is good to have a significant amount of space behind you if possible - this might mean sitting quite a lot closer to your speakers than you expect (or that you see other people doing).

 

Whether or not you have acoustic issues in your room, either in the mid or low frequencies.... remains to be seen.   If you do, then it can be first tackled through speaker and listener placement ... and sometimes with EQ (depending on the problem).    Be extremely careful arbitrarily "treating" the room to solve problems you don't understand, with solutions which won't work   

 

You may want to think about some floor and side wall treatment for early reflections .... however this does depend a lot on how close you are going to sit to the speakers (and how close the speakers end up to the sidewalls).

[HifiBruno]

Thanks to all for your input, great information. Helping me not to go in an ineffective direction. 

Have been given the go ahead to make the room larger when I remodel house a little latter in the year. So all will be useful in set up then.