Karsoncookie Posted February 11, 2015 Posted February 11, 2015 Planning on building a Crites Cornscala "original" w Crites woofer, K400 and K77 3 ways. Please don't laugh.I have a very basic Yamaha R8 2 channel receiver that has previously driven stock LaScalas to my satisfaction. Will be using it for these. No question there. Now I come across Klipsch Pro 2x15" bass bins for sale takeouts from a theater. I'm like "o cool double woofs for cheap" (Will be ordering xover from Crites and will tell him application.) Can I feed these 15" doubles in parallel w/o problems??? Lars Quote
Karsoncookie Posted February 11, 2015 Author Posted February 11, 2015 So I guess the question is - can I feed a 4ohm load with this receiver? or what do I do w/o buying another amp? Really can't afford that.Thank you again, Lars Quote
BusaDude Posted February 11, 2015 Posted February 11, 2015 (edited) I'm not familiar with the Yamaha, but if it has two sets of speaker outputs (an A & B ), then you could possibly drive the Cornscalas off the A and the dual 15's off the B. And if you're having a crossover built, then you could probably have it configured so that both the L & R from the B set of outputs is sent to the dual bass bin. The only concern is that many of the older receivers that have switched A & B speaker outputs, may have reduced power when both speaker outputs are switched on (to protect from low loads). That's the only way I know to attempt it. Unless you have the owners manual, there's no way to know whether it would like a 4 ohm load or not. Edited February 11, 2015 by GPBusa 1 Quote
colterphoto1 Posted February 11, 2015 Posted February 11, 2015 If the cornscala is 4 ohms and the double 15 are 4 ohms (likely 2x 8 ohms speakers), that is a 2 OHM load and I wouldn't try it with any home stereo receiver unless you want burn it up in a hurry. Using A and B outputs is the same as plugging them into the same output, it's just a switch, outputs are still in parallel, so that's no solution. Crossover won't help unless you put a huge resistor in there to change the impedance and that's just a waste of amp power. No, get a nice pro power amp for the dual 15's, drive it off a pre-out of the receiver (hopefully it has that. You can still use the receiver's built in amp for your Cornscalas. Consider the amp and double bins a subwoofer system and insert an active crossover network for it or you're going to have a mess on your hands. More speakers .not equal. to better sound in many instances. This might be one of them. 3 Quote
Karsoncookie Posted February 11, 2015 Author Posted February 11, 2015 Thank you, to clarify I mean the double 15"'s on each Land R, instead of my original Cornscala idea single 15" from Crites on L and R channels.. 4Woofers total instead of two. Lars Quote
colterphoto1 Posted February 11, 2015 Posted February 11, 2015 http://www2.yamaha.co.jp/manual/pdf/av/english/AFR/R8.pdf?_ga=1.32039038.136102489.1423646037 see page 5. When two pairs are connected, suggested that they be 8 ohms each. You're attempting to push way too many woofers with far too little power. Quote
Karsoncookie Posted February 11, 2015 Author Posted February 11, 2015 8 Drivers total. Stereo - 2 channel- each speaker would have 2- 8 ohm woofs, one K44/K55 and one K77. Only difference from a typical Cornscala setup is an extra woofer on each channel. Sorry if I mispoke. Lars Quote
cradeldorf Posted February 11, 2015 Posted February 11, 2015 (edited) I can't see why not I drive my KLF's with a 2 channel Harman Kardon and it's got 2 woofs per side + a mid and tweeter per side... gonna be fun trying to get it all to sound good together but if you get that licked... Edited February 11, 2015 by cradeldorf Quote
colterphoto1 Posted February 11, 2015 Posted February 11, 2015 oh so just the double woofer bins with mids/highs added? Yes you'd be ok. Individual woofers should be 8 ohms in parallel that's a 4 ohm load which you'd be safe with. i'd thought you were adding them to the complete Cornscala setup which would be murder. 2 Quote
Karsoncookie Posted February 11, 2015 Author Posted February 11, 2015 Cradel and Colter - Ya you guys got it. I see now how my originating post may have been confusing. Thank you, Lars 1 Quote
mark1101 Posted February 11, 2015 Posted February 11, 2015 You could instead use ALK networks which are constant impedance. Rewire the woofers to be in series on each box which would be at 16 ohms and use a swamping resistor to bring the HF to match the 16 ohms. Your receiver would see 16 ohms on each channel. Just another way to do it if you are concerned about burning up your amp, or worse yet clipping and burning up your speakers. Quote
beeker Posted February 12, 2015 Posted February 12, 2015 specs for the yamaha r8 say it can deliver 85 watts x2@8ohms or 100 x2@6ohms You could possibly go ahead and try the 4ohm load and if you feel much(use your best judgment)extra heat dissipating from the Yamaha r8 vents. keep volume level very low testing then possibly a bit more at a time for testing. you will not need much power considering the efficiency of the cornscala. but even without extra heat it may fail. That said I myself have ran many receivers very hard(years ago when I really didn't care, I do now)and have seen many others run receivers as hard or more and never had an issue. The total harmonic distortion obviously will raise as you raise your ohm load. Some units actually take the load very well. As mentioned a large power amp would be a wise choice to save the wonderful speakers you are putting together from clipping. A bit more patience and possibly trading your receiver or buying a quality/you tested used pre&. This will provide a much better lasting foundation for many years. I looked the Yamaha r8 up and it appears to have pre-outs so all you really need is a power amp. The best choice is a power amp running from your Yamaha r-8 pre-outs. Considering just a bit more time/patience and find a descent quality used power amp and you will be good to go. I do see that the Yamaha r-8 is no doubt good at 16ohms. The R-8 is actually a nice looking heavy duty receiver 3 Quote
cradeldorf Posted February 12, 2015 Posted February 12, 2015 Or you could do an impedence sweep of the finished speaker and see where the impedence really lies. Most likely it could go down or below 4 at some point but if it's at a frequency that isn't played constantly it probably won't be enough to bother your amp. Quote
Karsoncookie Posted February 13, 2015 Author Posted February 13, 2015 Good info. Makes sense. Thanks all. Beeker - Thanks for the FYI re: pre outs. I never noticed that. I assume you mean the RCA's marked"Accessory" with jumpers between the "Send" an "Receive"?? So I'd pull the jumpers, "Send" to a power amp and leave the "Receive"'s unconnected. Yes? Lars Quote
beeker Posted February 13, 2015 Posted February 13, 2015 (edited) Good info. Makes sense. Thanks all. Beeker - Thanks for the FYI re: pre outs. I never noticed that. I assume you mean the RCA's marked"Accessory" with jumpers between the "Send" an "Receive"?? So I'd pull the jumpers, "Send" to a power amp and leave the "Receive"'s unconnected. Yes? Lars Yes. The "send" rca's will provide pre-out's from your receiver. Hook the "send rca's" to a power amp then speaker wires to the preamp. EDIT:TYPO. AMP not pre Edited February 13, 2015 by beeker 1 Quote
Karsoncookie Posted February 13, 2015 Author Posted February 13, 2015 Beeker - "then speaker wires to the preamp" ?????? I think you meant to say"to the power amp speaker outs" Clarify please. Lars Quote
beeker Posted February 13, 2015 Posted February 13, 2015 yeah your correct. you got it. wires from the amp. ironically I was switching amps when I wrote that. if its your 1st power amp watch out. once I started buying amps it was just as bad as buying speakers. hopefully you will just stop at 1. its all anybody needs for the most part Quote
Karsoncookie Posted February 13, 2015 Author Posted February 13, 2015 Beeker - Again, thank you. My Yamaha r8 - which for me I know will be adequate (we all have differing $ limitations) will be more than adequate after I get it cleaned up from 9 yrs of hot humid storage.(Deoxit by a historied tech, not going to risk it myself, no experience) If that doesn't work, I'm going to look at getting a Crown 300- one of the models. Again, I need to keep the $ down and I'm very happy you pointed out the "pre" option. Lars Quote
Karsoncookie Posted February 13, 2015 Author Posted February 13, 2015 Beeker - I'm VERY happy to know I already have a Pre amp (basic as it may be) (if it cleans up scratchiness wise, etc,)if I want to get a separate power amp. News to me. Sorry, budget. No $1000 tube pre's for me. Lars Quote
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