Speakers in cabinets

[Markyboy]

I'm in the process of building 2 component cabinets (out of MDF) which will flank the tv, one on each side. These closed-back, open-fronted cabinets will also house the KMs that I use as mains on the top shelf. I have measured the height at which these speakers will be sitting off the ground and they will be perfect. The top shelf will be large enough for the KMs to stand vertically (14") with plenty of room behind them (13"). The remaining 4 shelves will house DVDs and CDs as well as my components.

My question is: Will having the mains moved into a "cabinet" create unforseen audio difficulties?

(I should say that I chose MDF because it not only looks good painted black but I was told that it won't vibrate like plywood.)

Any thoughts would be greatly appreciated. Like I said I am in process and can still make adjustments if necessary.

[dougdrake]

I'm guessing these are KM-2s? They are rear-ported. You may find that your cabinet creates a boominess, or may inhibit the operation of the port. If you do this, I believe you'll need to leave plenty of room around the speakers for proper air movement.

[marksdad]

i want to expand on what doug said, putting a ported speaker in an enclosure will flatly eliminate a good deal of the natural sound the speaker was ported to develope, i at first did this (partially) with my sons rf 3's and 5's, i did this for room restrictions, and honestly they sounded anemic, and i knew that when i used them in my first ht, they sounded wonderful, so i searched my memory bank and remembered that the speakers needed room for the ports to breath, so i rearranged the furniture to allow for repositioning of the speakers, and walla the reference again sounded like klipsch, be carefull to not give up sound for asthetics

[Markyboy]

The internal dimensions of the shelf will be 18.5"w x 24"d x 14"h. The dimensions of the speaker are 9"w x 9.5"d x 13"h. That leaves quite a bit of room for the ports to move air. Plus the back of the cabinet will have a cut-out for cables to pass through. With the speakers sitting on the front edge of the cabinet shelf (to avoid any reflection of sound) that would leave almost 13" behind it and 4" on either side of it to breathe. Is that enough room? Like I said before, I can still make changes, like opening the back of the cabinet more, making the shelf bigger, putting the speaker on top of the cabinet with a custom "wedge" to aim them down toward the listening position.

[PhilMays]

Can you make say a 1"-2" space right above the shelf running the length of the shelf?

[colterphoto1]

I like your last option the best, leaving the speaker cabinets on top of your entertainment cabinet (assuming it's not so high that there is a falling object danger) and tilting them forward. (maybe a strap attached to speaker back and rear of entertainment cab would prevent falls) All you have to do is feel the outside of a cabinet at moderate volume to realize that there is some vibration there. The designer intended for this to go into free air. If you trap it in any size box, there is going to a 'boominess' that you will despise.

Before you build the whole shelf unit, piece together a sample of approximately the size your speaker shelf will be, insert speaker, turn it on and see how it sounds. My guess is that there will be a 'tubbiness' that can't be ignored, especially with the rear ports. If you can ELIMINATE the back where the speaker is installed (ie make the opening a very close fit, yet allow the bass port complete room to breath to the rear of the cabinet, might be your best chance for a custom built in look. I did something similar with some of my brother's speakers years ago and it turned out alright. Built another bro's speakers into a wall unit with closed back- instant 'tub' bass. Let em breath!

best wishes.

[IndyKlipschFan]

This is a truely unscientific way of solving your problem...I had a friend, not me, that used air conditioner hose taped/glued?? the backs to a tight seal..wrapped the ports around to the front because he had cloth in front of the speaker like a door. Looked ugly, but you never saw it.

I happend to think it sounded great.. Can't prove why it was good or bad.. but it worked for him.

(I am sure others will kill me for suggesting this, but it did solve his rear port dilema too. It sounded like crap before he bent it around to the fronts in the box...)

[Markyboy]

Thank you so much guys! I really appreciate all of your insights. That's what makes this forum really work so well. I am going to divide the top shelf so that the speaker will sit in it's own enclosed (with an open back) section in the center of the top shelf. The two compartments to the left and right of this section will be further divided to hold CDs. That way the speaker will look like it is "built into" the cabinet. The compartment will be close to the dimensions of the speaker so that you can't really see that it is wide open behind it. Will this configuration eliminate any "tubbiness" or will this cause any other problems?

Thanks guys.

[Steve W. Bailey]

Markboy,

You may want to build the cabinet to accept one of the Refernce bookshelf speakers if you ever decide to update your KM's (the RB bookshelf speakers are front ported and tend to work better in this type of application).

14.8" smallest so far for RB-25's...just a thought, trying to think ahead.

[Markyboy]

I've been thinking about this and I do like the idea of reshaping the top shelf of the cabinet to give the speaker a "built-in" look plus it would give me some smaller shelves for CDs, remotes, etc....but, I was also wondering about indyklipschfan's friend's idea to use a tube of some sort to reroute the port's exhaust. What if I were to use a "tube" (of what material I don't know - maybe radiator hose) to route the exhaust through a hole in the rear of the cabinet eliminating the need to cut a section of the back out. The cabinet will not be against the wall so there will be open air from there. Would this be acceptible? Any thoughts?

[Markyboy]

bump