Coytee Posted February 12, 2008 Share Posted February 12, 2008 That is very cool to offer up an audition. It's one that I am going to take you up on. I'll try to schedule something around a near future business trip to Asheville if your schedule permits that, of course. You're welcome. There are no real calandar issues with me in general however, come May 15 I'm going on trip for almost 4 weeks so it would benefit you to be here prior to that or after mid June. Maybe I could simply hire you to house sit the dogs while I'm gone? Your payment would of course, be unfettered use of the Jubilees [^o)] Quote Link to comment Share on other sites More sharing options...
jwc Posted February 12, 2008 Share Posted February 12, 2008 you need the the sub to have about the same radiating area as the horn mouth you just crossed from Roy...I would like to think through this statement more thoroughly. Are you refering to the actual "exit" mouth of the horn or the calaculated mouth that is using the room for extension. For example, the exit of the jubilee is around about 140cm length of horn but the corner placement puts the mouth out there at about 192cm. So the mouth is much bigger than what we are seeing at the "exit" of the horn. So what value do I use to compare the mouth area of the horn vs the area of direct radiators? If it is the "exit" of the horn, then I would think the sub match for a la scala pair would need to be about 3-4 18" woofers. So Two KPT-684's?[]. jc Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 12, 2008 Share Posted February 12, 2008 Doing the Xti's on both horns is as you heard, pretty killer AND gets you the 48 db/slope that the Dx-38 won't fully do You can construct 48 dB/octave (8th order) Linkwitz-Riley crossovers by cascading two 24 dB/octave (4th order) Butterworth filters. The Dx 38 can do 24 dB/octave Butterworth filters, no problem. Greg Quote Link to comment Share on other sites More sharing options...
Deang Posted February 12, 2008 Share Posted February 12, 2008 I thought Linkwitz-Riley was cascaded Butterworth filters. Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 12, 2008 Share Posted February 12, 2008 I thought Linkwitz-Riley was cascaded Butterworth filters. It is. 2nd order LR is two cascaded 1st order Butterworth. 4th order LR is two cascaded 2nd order Butterworth. And so on. Looking more closely at the Dx 38 user's manual, I see that it offers 4th order Butterworth filters in the crossover functions, but only 2nd order in the filter function. So it's not quite as easy as I originally thought, but it can still be done with a 4th order Butterworth crossover, two 2nd order lowpass filter sections, and two parametric EQ sections. Greg Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 12, 2008 Share Posted February 12, 2008 you need the the sub to have about the same radiating area as the horn mouth you just crossed from Roy...I would like to think through this statement more thoroughly. Are you refering to the actual "exit" mouth of the horn or the calaculated mouth that is using the room for extension. For example, the exit of the jubilee is around about 140cm length of horn but the corner placement puts the mouth out there at about 192cm. So the mouth is much bigger than what we are seeing at the "exit" of the horn. So what value do I use to compare the mouth area of the horn vs the area of direct radiators? If it is the "exit" of the horn, then I would think the sub match for a la scala pair would need to be about 3-4 18" woofers. So Two KPT-684's?. jc yep. horn mouth area vs radiating area of the woofer. the loading should be very similar for both; what i mean if you put the horn in a corner, then the sub should be in a corner as well. if not, you will have to compensate for the loading. now remember, i said you would begin to approach........ in Christ, because of God's grace, roy Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 12, 2008 Share Posted February 12, 2008 Hey fellas; here is a good question for you. For those that plan on using subs with the jubilee, what advantage is there for the jubilee system vs the jubscala? jc now we are getting somewhere. Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 13, 2008 Share Posted February 13, 2008 now remember, i said you would begin to approach....... Keele seems to think that you can get more efficiency from an array of direct radiators when compared against horns of the same volume:http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1976-05%20AES%20Preprint)%20-%20Efficiency,%20Horns%20vs%20DR.pdfDoes anyone see anything biased in the correlation between the math and the measurements? (Like is the horn in question particularly crappy?) I dunno if polars are a tradeoff at the lower frequencies since they're gonna be too wide and then dominated by the corner of the room... Bummer there weren't any plots for distortion, or more horns tested... Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 13, 2008 Share Posted February 13, 2008 Hey fellas; here is a good question for you. For those that plan on using subs with the jubilee, what advantage is there for the jubilee system vs the jubscala? Ignoring the lower frequency extension of the Jub LF, I think it sounds better in the frequency ranges that they both operate in. It's not a huge deal, but once I honed in on it, I couldn't ignore it... Quote Link to comment Share on other sites More sharing options...
Deang Posted February 13, 2008 Share Posted February 13, 2008 Keele is a traitor. Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 13, 2008 Share Posted February 13, 2008 Keele is a traitor. That paper was written in the 70s. The laws of physics have changed since then. [] I used to work with Don Keele. I think that he would find your comment to be humorous. He has forgotten more about horn physics than most of us will ever know. As with all things "audio", there is more to it than just the math and the measurements. It is the intangibles that we enjoy. Greg Quote Link to comment Share on other sites More sharing options...
Deang Posted February 13, 2008 Share Posted February 13, 2008 "I think that he would find your comment to be humorous." That would be a good thing, since that's how I meant it. "As with all things "audio", there is more to it than just the math and the measurements. It is the intangibles that we enjoy." A quote worthy of sig line status. Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 13, 2008 Share Posted February 13, 2008 "I think that he would find your comment to be humorous." That would be a good thing, since that's how I meant it. OK, just checking! Seriously, Keele is very pragmatic about speaker design. If his goal is to maximize efficiency, then that's exactly what he'll maximize, in a very objective fashion. Give him a different optimization parameter, and he'll do whatever it takes to optimize that. As audiophiles, we exist in a slightly different world, one that is far more subjective. Greg Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 13, 2008 Share Posted February 13, 2008 now remember, i said you would begin to approach....... Keele seems to think that you can get more efficiency from an array of direct radiators when compared against horns of the same volume:http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1976-05%20AES%20Preprint)%20-%20Efficiency,%20Horns%20vs%20DR.pdfDoes anyone see anything biased in the correlation between the math and the measurements? (Like is the horn in question particularly crappy?) I dunno if polars are a tradeoff at the lower frequencies since they're gonna be too wide and then dominated by the corner of the room... Bummer there weren't any plots for distortion, or more horns tested... all horns are not created equal....... in Christ, because of God's grace, roy Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted February 13, 2008 Share Posted February 13, 2008 Keele is a traitor. That paper was written in the 70s. The laws of physics have changed since then. I used to work with Don Keele. I think that he would find your comment to be humorous. He has forgotten more about horn physics than most of us will ever know.As with all things "audio", there is more to it than just the math and the measurements. It is the intangibles that we enjoy. especially if they are chocolate covered....Greg in Christ, becaue of God's grace, roy Quote Link to comment Share on other sites More sharing options...
Edgar Posted February 13, 2008 Share Posted February 13, 2008 especially if they are chocolate covered Oh, Roy, I just got this mental picture of a Jubilee constructed entirely of chocolate. Brought a big smile to my face. Greg Quote Link to comment Share on other sites More sharing options...
Deang Posted February 13, 2008 Share Posted February 13, 2008 Roy "Wonka" Delgado. roywonka Man, you're in trouble now, that might stick. Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 13, 2008 Share Posted February 13, 2008 you need the the sub to have about the same radiating area as the horn mouth you just crossed from ...Are you refering to the actual "exit" mouth of the horn or the calaculated mouth that is using the room for extension...So what value do I use to compare the mouth area of the horn vs the area of direct radiators? If it is the "exit" of the horn, then I would think the sub match for a la scala pair would need to be about 3-4 18" woofers. So Two KPT-684's?. jc yep. horn mouth area vs radiating area of the woofer. the loading should be very similar for both; what i mean if you put the horn in a corner, then the sub should be in a corner as well. if not, you will have to compensate for the loading. now remember, i said you would begin to approach........ in Christ, because of God's grace, roy Let me see - four 18" woofers that can take the operating lf down at least an octave from the Jub lf cabinet in the corner position... By the way, is there a response/phase curve on the Jub lf bin while in a full corner? I would think we are talking about two subs that have strong, undiminished output to an octave below about 32 Hz, right? My calculation says--drum roll--16 Hz. What subs have two 18" woofers and undiminished output down to 16 Hz? Four Epik Conquests - mounted in the corners? Actually, as I recall, the Jub lf bin is a bit bigger in the mouth than the Lascala, isn't it? Quote Link to comment Share on other sites More sharing options...
Chris A Posted February 14, 2008 Share Posted February 14, 2008 Of course, there is the Eminent Technology TRW "fan subwoofer", but it needs a large custom-built antechamber to kill the fan noise (and about $20K to acquire) to install. But it goes down to 2 Hz, and a single unit will do ya... Quote Link to comment Share on other sites More sharing options...
jwc Posted February 14, 2008 Share Posted February 14, 2008 Jub exit about 750sq in and scala about 500sq in. Quote Link to comment Share on other sites More sharing options...
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