jhoak Posted June 11, 2011 Share Posted June 11, 2011 I have a valance that hides a pull-down screen mounted above the plasma TV in the living room. I want to set a single Heresy on top of the valance to act as a center between a pair of Cornwalls (or Cornscalas I haven't decided yet). Here's an old picture of the living room. The valance is in the upper right of the photo. I have already calculated that in order to be aimed properly in needs to angle downard at 22.5 degrees. The problem is that the Heresy is 1" too deep to do that. In order to make it fit up there at the correct angle I need to cut a bit off of the back edge of the cabinet. A total of 1" off of the bottom and 2" off of the back at the correct angle. If I did the math right this will result in 60.75 cubic inches less cabinet volume or 1.8% of the overall volume. So... The question is... How much effect will losing 1.8% of the cabinet volume have on the sound of the Heresy? And what whold the effect be? Less bass output I assume? THANX! Quote Link to comment Share on other sites More sharing options...
Dan308 Posted June 11, 2011 Share Posted June 11, 2011 I would think the strange sound would come from the center being 8ft high while the mains are 3ft high. Quote Link to comment Share on other sites More sharing options...
jhoak Posted June 11, 2011 Author Share Posted June 11, 2011 Actually not as bad as you would think so long as the center is "aimed" correctly. I've been using a KG-2.5 as a center and it's OK but it's just not "voiced" even close to the Cornwalls. It took some experimentation to get the angle just right but once I did it all blends fairly well. A lot of the credit for that goes to the AVR for correctly identifying the difference in distances and making the needed adjustments. I'm just trying to get a center that is closer in voicing to the Cornwalls than the KG is. The surrounds are going to be Heresys so I'm cobbling together another Heresy for center duty. THANX! jhoak Quote Link to comment Share on other sites More sharing options...
moray james Posted June 11, 2011 Share Posted June 11, 2011 A two % volume shift in a cabinet will not have any significant impact on speaker response. If you wanted you could add a small amount of internal cabinet damping. In theory you can obtain fron 20 -25% apparant volume with a fully stuffed cabinet volume but in practice it tops out at around 20%. So a few percent is nothing to overcome. Why don't you make a new baffle and turn the cabinet side ways so it will fit up there? You can then mount your tweeter in your Heresy vertically so you obtain its full 80 degree dispersion. I think the drivers would fit that way on a stock size baffle with your mid horizontal and your tweeter vertical. That is if this is a Heresy with a K77 tweeter. Great looking room by the way. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
MechMan Posted June 11, 2011 Share Posted June 11, 2011 jhoak Rather than cut up a perfectly good Heresy why not just slap a cabinet together that will fit to your area. Couln't be much harder than cutting up the Heresy. I would guess the only sonic diff would be the bass responce, which should not be a problem considering your mains Quote Link to comment Share on other sites More sharing options...
jhoak Posted June 11, 2011 Author Share Posted June 11, 2011 I'm not cutting up a "perfectly good Heresy". The cabinet in question was graciously donated to me by Groomlakearea51 (whom I will refer to in the future as GLA51 because I'm too lazy to type his handle out) and for whatever reason it does not have a stamped serial number nor do I have the original back panel with a label . As such it really doesn't exist as a "true" Heresy. It's just a cabinet that just so happens to be the same dimensions as a Heresy. I have no qualms whatsoever carving it up to fit my needs. Marshall (GLA51) gave it to me knowing that I was going to perform some fairly extensive "surgery" on it. Quote Link to comment Share on other sites More sharing options...
MechMan Posted June 11, 2011 Share Posted June 11, 2011 Aaah...Well then by all means, Hack away [H] Quote Link to comment Share on other sites More sharing options...
jhoak Posted June 11, 2011 Author Share Posted June 11, 2011 Moray, Thanks. It really is a great room for movies and music. I enjoy it a LOT. I wish I could turn it "side-ways" but that area above the valance also contains the outlet of my IB subwoofer. If I were to lay the Heresy on its side AND keep it centered it would block a significant portion of the IB opening. Standing upright is my only real choice. I really didn't think that a <2% change in cabinet volume would have a huge impact. I really couldn't see how it could but thought it was worth asking just in case I was completely wrong. Not like THAT'S never happened before... [] Quote Link to comment Share on other sites More sharing options...
cfelliot Posted June 11, 2011 Share Posted June 11, 2011 I do this with a center Heresy. Height to center of L/R Heresy IIIs is at about 36". The center channel Heresy I is at 72" to center of speaker. The primary seat is 12 ft back. The ideal angle would be about 12 degrees, I use 8 degrees (not in this photo). Sounds great! Quote Link to comment Share on other sites More sharing options...
moray james Posted June 11, 2011 Share Posted June 11, 2011 You still might consider cutting a new baffle for your Heresy cabinet. You can slide the mid horn over to oen side and have plenty of toom to mount the K77 vertically. The horn on a K77 is a diffraction horn designed by EV and when oriented vertically it has dispersion of 80 degrees horizontal and 30 degrees vertical. So vertical positioning of your tweeter will make a big difference. Keep us posted as to what you end up doing. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
willland Posted June 11, 2011 Share Posted June 11, 2011 It really is a great room for movies and music. I enjoy it a LOT. I second that. Jeff's room and system(in photo, mains now Cornscalas) sounds awesome. Very smooth with really good bass response. I think a FrankenHeresy center would be a great addition. Bill Quote Link to comment Share on other sites More sharing options...
jhoak Posted June 12, 2011 Author Share Posted June 12, 2011 Thank you!!! At the moment I'm running a pair of 87 vintage Cornwall IIs. I have the Cornscalas at the 98% complete stage. The Cornwalls and Cornscalas have been on a 24 hour "rotation" here for the last few days. I listen to one for a day and them swap them the next morning for the other pair. I'm having trouble deciding which pair to keep and which to sell. Here's the current setup: Quote Link to comment Share on other sites More sharing options...
wuboy Posted July 5, 2011 Share Posted July 5, 2011 I agree, I use a Quarter as a center channel, it already has a bass line, so rolling it at 80 hz (THX compliant) is no problem. Quote Link to comment Share on other sites More sharing options...
Pete H Posted September 30, 2011 Share Posted September 30, 2011 So... The question is... How much effect will losing 1.8% of the cabinet volume have on the sound of the Heresy? And what whold the effect be? Less bass output I assume?Long after the fact but something I just happened upon today was that if you look at the specs on a KP-250 vs a KPT-250 there seems to be very little difference in the response but quite a bit of difference in the volume of the cabinet but how that would affect a non ported Heresy I wouldn't know, but in looking at the KP series I would expect to see a different port size to keep the low end response comparable but they appear to be the same? I'm not sure what, if anything relevant, I just said but my questions started this morning regarding taking a pair of 250's and using them for sides or rears and then looked at the KPT and thought I could just cut the proper angle in. Quote Link to comment Share on other sites More sharing options...
Schu Posted September 30, 2011 Share Posted September 30, 2011 if you mount the heresy from the back instead of trying to rest it on that shelf, you would be better off! Quote Link to comment Share on other sites More sharing options...
Pete H Posted September 30, 2011 Share Posted September 30, 2011 if you mount the heresy from the back instead of trying to rest it on that shelf, you would be better off!Not being sure exactly what you were refering to; I would have to respond by saying seven. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 1, 2011 Share Posted October 1, 2011 What if you cut the top half of the Heresy and made it a squaker/tweeter two way, and made a square enclosure for the woofer deeper so you have the cu ft volume for it to maintain its voice? The mid/high could be mounted with plenty of room below the screens, and then you only need contend with the woofer box up high. As lower frequencies are less directional, you might not notice any elevation difference at all. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 1, 2011 Share Posted October 1, 2011 and here Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 1, 2011 Share Posted October 1, 2011 front Quote Link to comment Share on other sites More sharing options...
Captn Bob Posted October 3, 2011 Share Posted October 3, 2011 The primeval Heresies were designed to be used as center channels and were considerably shallower than today's Heresy. The worst that could happen is you'd lose some low end, which probably would not be a problem in your case. Quote Link to comment Share on other sites More sharing options...
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