Need help/advice with speaker porting.

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I am in the process of building an false chimney breast to flush mount my tv etc. My idea was to sink the centre speaker (Q Acoustic 2000i) into the false wall just above the cabinet.

Below is a picture to give you an idea of how it looks, although the box for the speaker now has sides all round except the front.

The problem is that now the speaker is in a box it sounds terrible. What can i do to get round this? I have been doing a bit of reading and it would seem i can either plug the ports as the 2000ci are rear ported, or move them further from the wall, in this case make the box deeper that the speaker is sat in.

So if i just port the back of the box i have built to sit the speaker in would this work. Or would the sound still not be right as in effect the speaker is still ported into a sealed enclosure, all be it a rather large one?

Any help appreciated.PS - Go easy on me, im new here

 

[RobinKidderminster]

Woops! Nice idea but I recon you need some expert advice. Rear ported centre is going to be a problem. I would guess options are to change to different centre with no rear port or to 'bung' the port and open the back of the box as much as possible. Looks like it doesnt need a back. Great that you have tried things before completing the project - be good to see pix of its progress too.

I had problems with a rear ported centre inside a cabinet. bunging helped but better now with a nn ported centre. I think you will get away with it without a back but someone may tell you that the air still needs an escape route into the room??

I dunno !

cheers

 

[Anonymous]

Woops indeed, lol.

As you can probably tell I am a bit of a noob when it comes to home cinema. I had the speaker positioned in its current housing, but without being enclosed and it sounded spot on, so i really want to try and get it back to when it sounded good.

Think i might try and port/remove the rear of its enclosure and see how that works. Annoyingly though i wont know its effect until the whole thing is complete, so some advice would be great

I'd quite like to try and make this centre work first before going down the route of a replacement as i have the Q Acoustics 1050 floor standers to match, and from what i can gether its not such a great idea to mix and match fronts...

Full build is in the below link...

http://www.avforums.com/forums/home-cinema-building-diy/1664529-my-first-av-build-false-chimney.html

 

[Anonymous]

I am in the UK, and by your username, RobinKidderminster, it would suggest that i am not too far away in Droitwich (WR9). As far as room design goes i have tried to consider this as much as possible, but the room itself isnt huge so i am somewhat limited to what i can do.

Your more than welcome to pop in for a cuppa though, will be in all weekend, just drop me a PM and i will send you my details. I would very much welcome any further advice.

Also thanks for the heads up on contacting the manufaturer, i think i will give this a try as if anyone has the answer it will be them.

 

[RobinKidderminster]

Fascinating build. I would have loved the space to do something built in like this. Good luck with it. I would suggest, unless people with greater acoustic knowledge interject (and maybe you could email speaker manuafacturer etc), that you try to 'open' the centre speaker as much as possible. Instead of solid side or back panels using matching speaker cloth or acoustically transparent materials. I dont know if 'venting' the sides may be useful too but a greater expert than myself would need to comment. Your obvious skills would suggest that you could make these elements an integral part of the design so it would still look great.

An interesting design & build and an interesting question regarding the way that porting operates. Keep us informed and my advice, for what its worth, is to try it out at any point you can to see if it works.

PS I am a room management fan and wonder if you have considered acoustic treatment. I think this would be as important as anything in a room which is clearly being designed with home cinema in mind. R U in UK? Can I pop in for a cuppa? When its done and after any overalls are dress code. Good luck - great project.

Cheers

Basically, looking again at your build, there seems to be plenty of options for replacing any solid panels with a speaker grille cover type material. Certainly the whole of the centre speaker box but additionally maybe a side panel and above the centre. depends on your decor too I guess. As much openess as possible without compromising the overall look/design.

 

[Anonymous]

I just called the technical help for Q Acoustics and they more or less said the same thing, in that the speaker is not designed to go inside a cabinet.

Using the baffles may 'help' but is not likely to cure the problem, and porting the enclosure is likely to cause an echo. I think i will do as you say and open it back up again and use a removable acoustic covering over the front of the speaker opening so it looks neat.

 

[RobinKidderminster]

If you are really bored try:

http://www.aes.org/tmpFiles/elib/20120831/11094.pdf

No help but hey ho. I dunno why its taken my interest but as wll as my previous ideas it has been suggested rockwool lined inside the 'cupboard' may help too. At least 6inches. I recon with some of these measures implimented you should be fine.

I found MS good when I bought their speakers. Richard Allen ofcourse is in Kidderminster. (I found out yesterday).

I thought I recognised your place - The Chateau ?

Cheers

PS - PM I dont think possible - pity sometimes.

 

[Anonymous]

Yep im just round the corner from the Chateau, small world hey.

Going spend some time this weekend and see what different effects things have. I will try and remember to report my findings. Oh and thanks for the link, that will give me something to do this afternoon whilst im supposed to be working.

If you want to pop in drop me an email to (without the spaces) s i m o n l p e a r c e @ b t i n t e r n e t . c o m

 

[RobinKidderminster]

Cheers Simon

Now get on wid yr work !

Ill be intouch.

regards

 

[RobinKidderminster]

Would be interested to hear about yr designs - thinking about the top speaker, which may benefit from slight angle down, a speaker type cover would work well maybe using the same surround as yr TV. (Silver or black). I sourced escellent cloth for my bass traps at very reasonable cost. I would be interested to know yr room size and where the seeting is. Back wall or away? Maybe time to think about (modest) room treatment dependant on use of the room and decor.

Jealous of yr blank canvass!

cheers

 

[Anonymous]

I hear what your saying on the speaker front, and definitely plan to angle it down. I see old squash balls seem to work well. My first plan is to just open up the back of the housing its in and see how that works. Failing that i will just remove the housing all together and it will sit within the breast of the chimney. I am sure, whilst not being ideal, it will be more than adequate space for the speaker to perform. In fact i may test it out by sticking it in a cupboard of similar size and seeing how it performs. I can also get hold of that sound foam from work as we use it to pad out electrical equipment when shipping so i can stick a load of this inside the breast if anyone thinks it will help??

As for room design i would do a google sketch but i dont know how, lol. The room is probably 7-8m by 4-5m but is split into 2 sections down the middle so you have a lounge/diner. Lounge at the front half of the house with a bay window and diner at the rear with patio doors.

I will have a single 4 seater sofa which is positioned about 1.5-2m from the TV and 1-1.5m from the rear wall. Id have the sofa a little futher back but we have a door which needs to open directly behind the sofa.

The rears will be Q Acoustic 2010's which will be stand mounted. I decided to go down this route as is offers more flexibility than wall mounted and allows us to move them out the way if needs be. I also read that they sound better on stands than the wall.

Infront of the sofa you have the chimney breast/av wall as can be seen in my link to the build thread. The chimney came out into the room a little further than expected because we had to isolate the gas fire properly but i am learining to live with it.

The walls will be totally skimmed and the floor will be carpet. Other than a coffee table there will probably be very little else in the room, so keeping it fairly minimalist.

Hope that helps to give a bit of an idea

 

[RobinKidderminster]

Squash balls - I mentioned them on another post and was told the black ones best . seriously I am going to get hold of a couple to try. Odd how no one else has chipped in yet.

I would suggest the setee position away from the wall is great (acoustically) although not sure how you can hide the wiring. It gives flexibility with rear positioning too. Shipping foam is not acoustic tho you probably know that. I understand that RW3/RS60 is better but it probably wont matter in this case??

For the centre I thought you had the idea of opening up the back, sides and possibly top and using a speaker grille type cover. I would think this would solve the problem without compromising sound or decor.

I also guess that yr floorstanders will be slightly inside the sides of the chimney breast. Corner bass traps (I think) would vastly improve the sound and could maybe be integrated into your design.

Cheers for now.