m00n Posted March 22, 2005 Share Posted March 22, 2005 Ok, as some of you know I run RC7s as my surrounds and rear. The problem is, they are rear ported and sitting flat up against the wall. Not good obviously. Thus, Ive been pondering two different solutions. 1) Create cubbies in the wall. Basically give some breathing room. This would be an extreme amount of work. I have 4 side surrounds. 2) Create an entirely new cabinet for my RC7s. One that was front ported and took on the look and feel of the following Klipsch KPT -250 cinema speaker. My thought is that I would rebuild RC7s cabs, take the drivers, horn, crossovers out of my existing cabinets and build something along the KPT style.My goals are: 1) Get the ports in the front so I dont have to tear into my walls to allow for the rear ported RC7s 2) Angle the speaker such that it points towards the seating area. This problem arises from the fact that with the RC7s standing on edge, the seating positions get very little pleasing affects. How hard is it going to be to figure out the cabinets dimensions? I realize there are some free speaker box software apps out there, but do they deal with complex shapes such as this? If not, are there any formulas I can use to help me out? I strongly want to entertain this idea of building some custom cabinets for my RC7 surrounds. I'm thinking a cabinet with a front layed out as such. By now many of you are asking. Why not just go with the RB75s since they are front ported anyway. Well, as Ive mentioned before, I think the RC7s wallop the RB75s. Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 Ok ok... Slooooooow down everyone... Don't you all jump in all at once and help. Ok... Someone on diyaudio was kind enough to give this to me... All I got to do is figure out the order of operation... Do you do division prior to multiplication or multiplication before division? Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 m00n, I personally think you're trying to reinvent the wheel, so to speak, but nonetheless, you asked, so here goes. Vout=C*D*A + E*(C+B)/2*A + D*B/2*A Multiply C*D*A, call this Z Add C+B, divide that by 2, then multiply that number by E. Call this Y Divide B by 2, then multiply it by D, call this X Now you've got Vout= Z + Y*A + X*A I sure hope I did that right!! And also hope it helps!! (Where's my slide rule when I really need it?) Owwww.. my head hurts now. Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 No no no my friend.. I'm *INVENTING* the wheel and that wheel being a new cabinet for the RC7s to act in surround duty. You see, the RC7s make for a great surround speaker with only 1 draw back. Well two actually if you stand them on end. 1) They are rear ported 2) If you stand them on end as I have, they are tooooo tall and sounds go WAY over your head. Indeed, I may be crazy, but I'm *INVENTING* Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 ---------------- On 3/22/2005 9:10:29 PM m00n wrote: Indeed, I may be crazy, but I'm *INVENTING* ---------------- LOL.. yes you are, and I wish you luck. However, it may be a LOT of work. As I recall, didn't you have like 12 RC7s on each side of the room? That's a lot of cabinet building!! Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 LOL.. No! Only 2 on each side. The rear RC7 will remain the the stock cabinet. I may not even do this, but it sure seems like a lot less work than a whole lot of construction in my walls. Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 I know Zip, Zero, Zilch, Nada about speaker design, but just to throw out a thought... Would it be possible to change the diameter of the port, be it larger or smaller, then simply add a U shaped extension to it to get the sound to come out front firing instead of rear? OK, I know just a very small smidgeon, something about port diameter effecting the extension and roll-off, or some such thing, but there has to be an easier way than rebuilding all new cabs, doesn't there? Hopefully someone much wiser than I will chime in with a new, profound idea that solves your issues without spending 100 hours on your saw, router, shaper, planer, joiner, anything I've missed? Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 So by my calculations, the volume of air in a RC7 should be 1929.375 Outside dimensions are 9x26x12 So... I subtracted the internal dimensions should be close to 7.5x24.5x10.5 BUT!!!!!!!! This is not taking into consideration the thickness of the veneer. Anyone know how thick that is? It can't be more than what? 1/16"? Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 Not thick enough to factor into your equation, IMHO. You're going to have more sizing errors due to miscuts and what have you than the veneer thickness would amount to. Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 ---------------- On 3/22/2005 9:36:28 PM Champagne taste beer budget wrote: You're going to have more sizing errors due to miscuts ---------------- ACK! That hurts man! Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 ACTUALLY laughed out loud. Maybe I should rephrase that.. I would have errors greater than the thickness of the veneer, which I believe is like 1/32 inch or some silly small number, because I don't have the quality equipment you have at your disposal. You feel better now? Quote Link to comment Share on other sites More sharing options...
m00n Posted March 22, 2005 Author Share Posted March 22, 2005 Yes... I do. Thank you. Quote Link to comment Share on other sites More sharing options...
Champagne taste beer budget Posted March 22, 2005 Share Posted March 22, 2005 We REALLY need to get this out of the m00n and CTBB mode. I KNOW someone out there has better answers than I do. I'm out for the night. 8:50, didn't get home last night till 9, gonna be 9:30 or so tonight. We can continue this fun in the AM. Good luck, have a good night. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 23, 2005 Share Posted March 23, 2005 hmmmm, this sounds like a really good idea for your room moon and it's a ton easier than ripping your walls apart too, lol. As far as dimensions go, the only thing to worry yourself about is keeping the internal volume the same as the original. To make things easier to build, you might consider getting rid of that whole "e" section and just making the top of the cabinet that dotted vertical line. Do you plan on putting the tweeter at the top or the bottom? I know your drawing made it look like it'd be on top...To save yourself some walking headroom, you might consider putting the tweeter on the bottom and making the whole speaker higher up on the wall. Make sure you leave enough space behind the drivers so that they will still fit. Also, that port should be twice it's diameter away from any internal boundaries (aka, the sides of the cabinet). Apart from that, all you need to do is tweak the dimensions to get your plan laid out and then start building. I was just thinking...you could also put the ports on the bottom of the speaker too (pointing straight down once you get it mounted up on the wall). I'm not sure how hard the wind blows from those ports, but it is certainly distracting when you feel something blowing on you. (I had a subwoofer near me that would blow hardcore during bass heavy scenes). You could also make your front baffle removable so that you could experiment with having the tweeter on the top or on the bottom as well. Are you still running a pair of RC-7's on each side surround (4 total side surrounds) and then 2 more RC-7's in the back as the rear surrounds? Have you experimented at all with angling the side surrounds slightly forward? Perhaps you could build your new front baffles so they angle to the front a bit as well Sorry for a rambling post, I was just brainstorming out loud for ya. I hope I'm not making you more indecisive Quote Link to comment Share on other sites More sharing options...
m00n Posted March 23, 2005 Author Share Posted March 23, 2005 DrWho! Thanks. Yes I was planning on tilting them towards the seating area. About a 30 degree angle from the top. Yes I had planned on putting the horn up on top. However, I'm open to options. The ports could be an interesting thought now that you mention what you mentioned. I was under the thought that I could just stick them where ever I wanted on the front baffle. I have 4 side surrouns, 2 on each side, and 1 single rear. As far as the cabinet design itself? Yeah I'm not all that sold on the exact design of the KPT. Even if was just a normal box with a tilted baffel would be just as fine. Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 23, 2005 Share Posted March 23, 2005 If this is meant for home use, you might want to consider putting the horn on the lower part of the baffle board to keep reflections from the ceiling. That would put the woofers closer to the ceiling/wall boundary, possibly increasing the low output (I'd experiment with a prototype box with removeable baffle boards so you can recut them and try them out b4 going into production. I think DrWho was speaking of putting the ports on the bottom edge, not the bottom of the baffle board. So the 'wind' wouldn't be blowing at listeners. Also consider the flared tubes to reduce wind noise. Neat idea Moon, would you be doing away with the tapered array portion of the network? It wouldnt really be required or possibly even wanted since this is not a dialog channel. Michael Quote Link to comment Share on other sites More sharing options...
ygmn Posted March 23, 2005 Share Posted March 23, 2005 Buy a KPT....hehehe Idea.... Cut hole in wall.... make shelf to hold RC7....how ever you want... now...line up behind the rear ports some 4" pipe.... Route this pipe in a U shape and let it vent back into room.... Would require deep walls...but maybe you could just make a rectangular tube shape out of sheetrock and then vent it down and below shelf speaker sits on and then vent into room there...... IF you have autoCAd I could draw what I mean.... Tearing up a good RC7 makes me cringe is all... Quote Link to comment Share on other sites More sharing options...
ygmn Posted March 23, 2005 Share Posted March 23, 2005 Atrtached find a jpg file of a quick and dirt AutoCAD drawing I did of what I meant in above post..... you could tilt speaker as desired by making shelf tilted....and then attach angle bracket at top and secure to rear of speaker to keep it in place...and then bring out the framing and sheetrock to be parallel to back side of RC7... I would seal ports with some thick foam so air travels through holes and through wall cavity to large port on bottom... Quote Link to comment Share on other sites More sharing options...
m00n Posted March 23, 2005 Author Share Posted March 23, 2005 Michael As far as the ports, i was referring to his comment "Also, that port should be twice it's diameter away from any internal boundaries (aka, the sides of the cabinet)". Just look at the speaker now, it's not like this. Wonder how Klipsch go around that. Like the idea of the removable baffles...Definitly like that idea. As far as the crossover goes....I dunno. I like the RC7s, I think they sound great. I will entertain the idea for sure. ygmm I won't be tearing up my RC7s. They will get packed neatly away back into their original boxes. Also, I don't have enough room in my walls. I would essentually have to create cubbies behind them that would extrude into the adjecent rooms. Believe me I've thought about this. And it would be an extreme amount of work considering the way I would want to implement it. Quote Link to comment Share on other sites More sharing options...
ygmn Posted March 23, 2005 Share Posted March 23, 2005 MOVE then!!!! hehehehe Quote Link to comment Share on other sites More sharing options...
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