Designing entertainment center with speakers in mind

 

New member
Username: Mm_putnam

Post Number: 1
Registered: Apr-05
I am a woodworker and will be building an entertainment center that will hose my A/V equipment. I have some and will be acquiring my surround speakers which will be B&W 201's,B&W LCR 60, and a M&K V-125 subwoofer.
The question is around building these speakers into the cabinets of the entertaimnent center.
Is it OK to build specific 'boxes' around the speakers? I'm asking if the speakers perform OK if they are enclosed on all sides? Or enclosed on sides but not the back?
I know the sub has special needs for venting - which I will take take into consideration, but want to know if all speakers need to sit 'in the open'?
Any advice would be appreciated.
 

Silver Member
Username: Touche6784

Post Number: 283
Registered: Nov-04
i believe that ported speakers perform best on stands and not in cabinets. I think acoustic-suspension speakers do better. I am not sure if opening the back will improve sound but it seems like a good idea. if jan ever sees your post i am sure he can give you some pretty good advice.
 

Anonymous
 
Matt, many posters feel that putting speakers in cabinets is a serious error. However, it is a fact of modern life that many people are building entertainment centers AND placing speakers in cabinets.

The biggest issue with your proposed idea is that the cabinet can become a "cave." In that case you could end up seriously damaging all the speaker fine tuning. Totally enclosing the speaker does not seem like a great idea either. You should play with different materials inside the cabinet to keep sound from bouncing all over.

I don't know if the B&W's are rear ported, but I would avoid placing a rear-ported speaker in a cabinet. The same goes for the sub. I would avoid all subs but a front firing one. Depending on your taste for entertainment a sub can make the best cabinet shake. Great bracing is necessary.

Finally, unrelated but useful, see if you can build rear access to the cabinet for ease of access to connecting equipment and speaker. It can be a godsend.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3567
Registered: May-04


The best way, in my opinion, to treat speakers in a cabinet is to do one of two things. First, instead of buying, and paying for a speaker cabinet that will not be of significant benefit to you, buy speakers from the same company that are meant for in wall installation. Look for similar drivers and make your enclosure the same approximate size as the cabinet you would have purchased. Most in wall speakers will be a non-ported design, which amounts to an acoustic suspension speaker. You can find information about sealed box designs by putting "D.I.Y. Speakers" into a search engine. A sealed box will be 3dB less efficient than a ported design but will have a less dramatic roll off in the bass compared to a ported design. The major concern in a sealed box is that there are no air leaks in the enclosure.

By making the enclosure air tight, you have created a form of infinite baffle. The rear wave cannot escape to negate the front wave. Infinite baffle is usually referred to in designing a bass enclosure, but its benefits extend to the high frequencies also. The second option you have is to buy a speaker that is in an enclosure and either sealed or front ported. This speaker should be mounted with the face of the speaker flush to the cabinet and with as much open "baffle" around the speaker as possible to suit your design. (Think cutting an opening in a 4'X4' sheet of ply and placing the speaker flush with the front edge of the ply. This creates a baffle that is larger than the frequencies the speaker will produce in the highest octaves. This broad baffle will give a slight booost to the highest frequencies and smooth response in that range by not allowing the discontinuity of a speaker placed in free space. If there is a disruption to the path of the sound wave from the tweeter to the cabinet face there will be diffraction and a difference in sound quality you may notice. Use foam or thick felt to line the cabinet enclosure and slide the speaker into the opening made by the foam. A sheet of panel damping material from a auto sound shop can be used first before the foam is added to reduce vibration further. You can also paint on a damping material from the same shop. The speaker should be snug fit with no play between it and the foam. If you don't use the grill that came with the speaker, use a similar grill cloth and chamfer or round over the inner edges of the front frame to cut down diffraction.

Speakers will sound best in this arrangement when the tweeter is situated at ear level for a listening position. This is typically about 36" high.



ACOUSTIC SUSPENSION
Mounting a speaker in a hermetic or air-tight enclosure traps a fixed quantity of air behind it. The springiness of this air can effectively replace the suspension spring used in speakers to return the speaker cone to its "normal" position, hence the term "acoustic suspension" (either "air suspension" or "pneumatic suspension" would be more accurate). The ADVENT, the AR 3, and the EPI 100 are (old) examples of acoustic suspension speakers.
Acoustic suspension speakers are traditionally much less efficient than bass reflex speakers and therefore need more powerful amplifiers.



http://www.mhsoft.nl/ClosedSystem_en.asp


 

Silver Member
Username: Paul_ohstbucks

Post Number: 616
Registered: Jan-05
Im not a big fan of any 'enclosed' system, because your 'future' system will often be restricted to the enclosure.

By brother-in-law bought a massive Sony 34" HD-Tube tv about 10+ years ago and built a fantastic ET center around his TV. Now he's stuck with it because his wife wants to keeep the Entertainment Center. I guess there will be no massive HDTV in his future:-(

E....gadz!! I feel sorry for him. The more you enclose, the bigger deal it will be if you ever plan to upgrade.
 

Silver Member
Username: Artk

Albany, Oregon USA

Post Number: 310
Registered: Feb-05
My god, I actually agree with Paul!
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3574
Registered: May-04


The simple answer to the problem Paul presents is to build two separate component enclosures and one expandable bridge piece. It is a more complicated design, but well worth the effort when a new TV is in order. Of course, if you're building for a 60-70" TV to begin with, the option of going larger is probably not that important.


 

Silver Member
Username: Paul_ohstbucks

Post Number: 636
Registered: Jan-05
LOL Arthur!!

And jan.......you have a point. My wife has even brought up that very thing(expandable center), but I killed the idea.

I told her that I've bought my last TV, and my next one will require a 10' screen and a projector, and to forget about her !@$$#% ET-center Idea.........LOL

My only regret is that I didnt research projectors before buying my 65" recently. I never really thought about a projector nor looked into them, and it was my mistake because my room is well suited.

Oh well.....live and learn, but no friggin ET center for this guy!! If you have suggestions for a good popcorn machine though, I'm all ears.
 

Silver Member
Username: Paul_ohstbucks

Post Number: 637
Registered: Jan-05
BTW...........the movie of the night was Spidyman2, and it was the third time I've seen it.

Love that flick!

Nothing beats having a HT and an archive of movies because any night of the week can be 'movie night'!!
 

Silver Member
Username: Artk

Albany, Oregon USA

Post Number: 323
Registered: Feb-05
Ain't that the truth! Movies are so cheap now that I don't even rent anymore, I just buy. We just started our collections. I have 150 movies and my wife has about 50. We have seperate collections as I don't want "Hope Floats" in mine and she doesn't want "Kill Bill" in hers. Enjoy the movies Paul.
 

Silver Member
Username: Paul_ohstbucks

Post Number: 649
Registered: Jan-05
Heh...

My daughter keeps hers upstairs, but my wife and I co-mingle ours.....hahah

I usually buy at least two a week for me not counting whatever mushy 'chick flicks' or kids movies that I pick up on request for the wife & kids.

It's very rare that I rent anymore. I see where season 5 of the Sopranos is being released in june and I'll rent those. BTW, the release of season 4 on DVD was probably the last time I rented. I love the show, but I'm not personally into collecting a TV series.
 

Renting is Better
Unregistered guest
http://www.dvdr-digest.com/software/software.php?file=dvdshrink
 

Silver Member
Username: Artk

Albany, Oregon USA

Post Number: 325
Registered: Feb-05
So far I've only collected one TV series, NYPD Blue. How much can you collect anyway they won't release anything past the second season. I like those perfromance DVD's. Miles Davis, Boz Scaggs, U2, Led Zep, lots of very cool video's.
 

Silver Member
Username: Paul_ohstbucks

Post Number: 657
Registered: Jan-05
I dont do music, nor have any interest in concerts. I've attended a few in my day, but for me.......music is for killing time between points A-B in a car, and that's about it.

Funny thing is that lately I listen to more talk radio than I do anything else.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 3582
Registered: May-04


Paul - Talk radio, of any kind, will rot your brain. It is a slow death that, like shock absorbers wearing out, one day slams you into a pot hole.

It also is hard on your dashboard as you constantly slam your fists into the dash screaming obscenities at the radio's talking head.


 

Silver Member
Username: Paul_ohstbucks

Post Number: 658
Registered: Jan-05
Heh
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