Mike Price

I built my crossovers from scratch , based on driver parameters measured with a WT3 , and frequency responses measured with TrueRTA and a calibrated measurement rig. I wound up using the peavey midrange driver because it's frequency resaponse was the easiest for me to work with , so the actual values would be very different for the atlas driver , but in my case all that was needed was a 1.8mh inductor with a 30ohm resistor wired in parallel , in series with the driver , and of course a 500hz 2nd order high pass to roll off the bottom end. With every driver I measured on that horn (H4427), it showed a rising frequency response , rising about 10db between 500hz and 4000hz. The way to compensate for this rising response is to put an inductor inline that corresponds to the frequency you want to begin your tilt (downward) then you put a resistor in parallel with that inductor , its value dictates how much tilt will be achieved , inm my case it took 30ohms , to tilt it down the 10db necassary to flatten the overall response. This does lower the overall sensitivity of the midrange by 10db , but it was somewhere around 118db 1w when I started , so it was no big deal. I hope I have explained this well enough , it's a really simple method , I may just not be very good at explaining it. The speakers are built , by the way , and they sound wonderful.

I ordered a pair of the H4427's from Gregs Pro Audio , they shipped quickly and are a quality product. I did some measuring which revealed a rising response on the H4427's , and they roll off around 550hz on the bottom end , which is good enough for my application. I build a simple contour network to compensate for there rising response , and began some listening tests. I directly A/B'ed them to the K-401's , and my impression is that the K-401's may have a slight coloration to them , despite measuring quite flat. I will be using the H4427's in my project , to my ears they just sound better , more open and clear. The tweeter will be an APT-50 on the Selenium baby cheeks lens. The woofer I decided on is a Peavey 18" Lowrider , and the midrange driver I am still undecided on. I have been listening to 3 different drivers that I have on hand some selenium D250-X's , some old EV1828's and some even older Peavey22A's. Believe it or not, out of all three pairs of drivers , the Peaveys seem to have the flattest response , lowest extenion , smoothest sound , and at this point are probably my first choice.This will all be housed in a set of 10 cubic foot cabinets that I built this summer after I sold those Cornwalls to Rockhound. I built cabinets with removable baffles and didn't like the driver alignment I chose the forst time around , so I got rid of the drivers , and am in the process of building the baffles for this new set up right now.I can post pics of them when they're done if anyone is interested , however at this point I have changed so many things from the original plan that they are no longer Cornscalas , just some really big , really efficient 3 way DIY speakers , sharing only the APT-50 and H4427's with the Cornscalas.

Thanks for all the input guys , I've got some decisions to make now , I have access to a few different mid drivers , and an apt-50 with both the apt-80 lens and the apt-200 lens. I also have a free pair of K-401's available ,and most of the components to build the crossovers. I think my next step may be to run some sweeps on each of the drivers mated with the K-401 , and then have a listen to which ever one yields the flattest/smoothest response. If I don't like the sound of the K-401 I will then look in to ordering one of the large fromat hors from gregs pro audio.I've also been toying with the idea now of not building the Cornscala , but using the K-401 and APT-200 on a different bass bin , I can get a pair of Peavey 18" Lowrider's for a steal right now , and modeling them up in bass box they look pretty darn good. To make all this decision making even tougher , I was planning on building this in to a cabinet that I alrady have built(removable baffle) tha is only 22" wide , for the K-401 or any of the JBL clone horns this is a non issue. My father has , besides the pair of K-401's a couple pairs of 511b's , that he would sell me pretty cheap , if not just give them to me. The problem there is they wont fit in my box and I would have to start all over which would make the 511b's an expensive option , even if the were free. Decision , decisions , why can't these projects ever be simple right?

Thanks DJK , I saw that one , I had got to looking at all the stuff on that website earlier when I was linked to that 2370 clone. Is that website pretty dependable ? Also , what exactly IS the problem with the K-400/K-401 ? because my father just informed me that he has a brand new pair of K-401's that I can have if I want to use them in this project , no charge.

Thank you very much FJD , that is exactly what I was looking for , and I figured someone around here would know where to find it.

I wish I could , go that route , unfortunately in these economic times my budget is extremely limited , I have a few pairs of 1" drivers on hand , and was looking to pick up a pair of horns for no more than $100 , preferably closer the the $30 a piece range like the Pyles were. I sure wish they wouldn't have discontinued thos horns.

I have gathered most of the parts to put together a pair of Cornscalas(of sorts) , but I just went to check what midrange horn he was using for the 1" driver version and it appears both of them are discontinued. Is there a new horn that can be used in place of either the ph-800 or the Pyle PH2380P ? Are either of these available and I am just missing it? I know there are some offerings from JBL and P audio that may work but they're quite expensive , and i was looking for something more along the price range of the discontinued ones. Any help on this subject would be great , thanks in advance.

I think you will be thrilled with it , I just picked up a 905 from accessoriesforless a couple weeks ago ($899 Free Shipping couldn't resist) , and I couldn't be happier with the thing , I wasn't prepared for the size of it though , so I wound up needing to build a new rack lol

Ok , it's in place and in use , and I'm pretty impressed with it so far. The surround sound from my blu-ray's is probaly some of the best I've ever heard through this thing , the two channel audio is good too , although there are a few quirks , like I love what audyssey did to my frequency response , but when you run in pure mode , it defeats , and the subwoofer goes away , also it trimmed my cornwalls back -12db in the auto speaker setup , so i find myself turning the volume fairly high to get them up to listening level , I havent had the chance to do any real critical listening yet ( wife and kids home ) but from what i have listened to i hear some pretty big improvements over my last setup , mainly in the bass , chello sounds alot more like chello instead of alot of boom , I'm thinking I might have had a big peak in my bass response that was responsible for this. My biggest concern prior to hooking it up was the heat , which seems to me has been blown way out of proportion , the back right corner , where the reon chip is , gets warm , but just warm , and it doesnt matter if the unit is just sitting there on , or running full tilt , it stays the same, so that was a relief. I've only had it hooked up for 2 days now so im sure I got alot to learn about it , but so far so good , definitley no regrets. Now I gotta get started on a new sub , cant decide between a Maelstrom-X and a RL-P18 but thats another thread.........................

I too , have my home theater directly connected to my kitchen , and dining room , and as you said , half the time its competing with the dishwasher or some junk like that. I litereally would have to double my investment to move up to separates , and probably for a difference in quality that I would really have to concentrate to notice. I have seen some very happy customers with the 905 , hopefully i will be too

Well , it's done my TX-NR905 is on its way , after weeks of research on the internet , I could find very little negative about this receiver , and a whole lot of positive. As far as the heat goes , I beleive with adequate clearance and a small ventilation fan it will be fine. The $899 price tag included FREE shipping , so to me thats a pretty good deal.

I am not 100% sure but I think the 905 and the 9.8 have all the same processing chips and DACS. I would get the 905 and listen first, then if not completely satisfied with the amp section, buy a two or three channel amp with more wattage and go from there. Bill Thats what I was thinking of doing , Buy the 905 , and if I'm not satisfied , add amplification across the front , and let the 905 handle the back 4. It seems to me that the 905 has the same preamp section as the dtc-9.8 , same dac's , torroidal transformer , independent power supplies etc. , BUT.... a close friend of mine swears that the seperate preamp will sound better than using the receiver as a preamp. even considering they are spec'd almost identically he says that seperates are just better quality components in general , myself , I think in a blind listening test with identical amplification its probably not that much different , IF some one has heard both setups , and can tell me that there is in fact audible difference , I will go the seperates route , but as of now it looks to me like the all in one package of the 905 will be just as nice

From everything I've read online , if I go the route of the receiver I'll definitely be adding a fan of some sort , it seems that the Integra also runs hot wich is said to be a product of the video processing and not the amplification. When I read that I was almost leaning toward going with a different setup all together , as I have no need for the video processing , like maybe a nice 7.1 analog preamp , but i really like the audyssey , and the networking capabilities. I agree totally on the heat and dust thing (dust creates heat in electronics) so I have every intention of adding a fan.

Yes , the $899 price tag is very tempting , I'm glad you mentioned the heat , I was planning on putting it in a custom rack , the space would be 11"x24" open front and back , is this room enough or should it have alot more that 3" above it for ventilation?

I understand that , what I'm wondering is if it's that much difference in sound quality going the seperates route .I have a few Adcom amps that I could use with the DTC-9.8 , but from what I've read about the 905 I'm not sure it's worth all the extra equipment and cabling. The cornwalls are in no way power hungry but are very revealing of the source , whether it be good or bad. I sure wish there were a local dealer where i could hear both of these for my self.

I am about to upgrade my receiver , and am considering going with the ONKYO TX-NR905 , which i can get for $899 right now , the receiver gets great reviews from what I've read , but I was wondering if any one here had experience with it , I will be using a set of cornwall-II's as mains and am very interested in good sounding 2 channel audio , my other option was to go with an Integra DTC-9.8 , with external amplification , considering the efficiency of the cornwalls , and the heft of the internal amps in the TX-NR905 , I believe it will suffice , but if theres any reason the DTC-9.8 will sound noticeably better I will definitely go that route. I'm not looking to get concert levels here , but would like to have excellent sound quality for music , and still have all the latest codec for HD movies , so if anyone has experience with either of these I'd like to hear your opinions on the subject , thanks.

I do hold a current louisiana journeymans license , you must have misread something there because i made no such suggestion , the fella stated that someone told him he would have trouble putting #10 wire on a receptacle , to which i replied that there were different rated receptacles that accepted different size wire accordingly. As far as "making sure his equipment is absolutely toasted" the breaker in the panel is in place to protect the wire , not the equipment. The fuse in the amplifier should protect the amplifier equally wether it be plugged into a 15amp , or a 30amp.

Sounds like you got yourself a pretty good plan there , I believe that the emotiva on top of the rest of your system is too much for that 15amp circuit , being that you have a spare 20amp accessable should work out fine , I had my whole system on one 15amp breaker at one point , and at peak action sequences in movies , or with bass heavy music , i could actually see the lights on the equipment dimming , then I added my EP-2500 to the mix , first movie I put on it tripped the breaker. So I ran another (30amp) circuit , and put my receiver and amplifiers all on it , worked out great. Also , I been looking at those emotivas , looks like very nice stuff for the money , I was considering Getting one of the 3 channel models for my front stage , rears really dont need it so i was just gonna keep them on the receiver.

Mike, in this situation, could you then just run a dedicated 2-wire circuit (say, 10 ga.), and an isolated ground (to a ground rod)? Yes you could , but with the dedicated circuit the ground rod isn't really needed. You havin trouble with ground noise , or ya just curious?

Thanks , the grounds can infact be all tied together , no code issues there , as far as driving a ground rod just for your audio equipment , it's an excellent idea , and is reffered to as an isolated ground , but its alot of work too. Most of your noise is usually going to come from othre appliances on the same circuit , or dimmers , ac adapters etc. as long as all you have on the circuit is audio equipment you should be ok. As an electrician and an audio enthusiast I highly reccomend running a dedicated circuit , or two depending on your needs , and it should be at least a 30amp cicuit , #10 wire , no splices anywhere. The general power circuits in houses are not designed with the power demands of a large sound system in mind , theyre there for lamps , alarm clocks and tv's , when you plug your amplifier in to a standard 15amp receptacle , is going through #14 wire , which is spliced at every other receptacle it powers , and often feeding lights in the room too , not an optimal power source for your sound system. I could go on forever with reasons why to do it , so I'll just leave it at this , if you have the means to run dedicated power , do it , its for the best

Ya know whats strange though , the TX-SR805 weighs in at 55 lbs , yet this years TX-SR806 only weighs 30 , hope this isn't a sign that their starting to cut corners , maybe they just changed the point in there line up to the 876 , where they start puting the bigger power supply , also the 805 is capable of like 60 amps instantaneous current , and the 806 only like 38 , apparently they changed something , and in the next few weeks when i buy mine , i'll definitely be going with the 805

At 75 feet , #12AWG is good for 20AMPS , or 2400 Watts at 120VOLTS , you should be good as long as there is nothing else drawing major current from that circuit. BUT if , for example , you plug in a vaccum on the same breaker , it would noticeably decrease your amplifiers output.

Now I'm curious WHY? I was thinking of going with another rc-62 my self , one above and one below the screen , so this is a bad idea?

Just realized i skipped something , as you reach the maximum amperage of the wire the voltage goes down too , long before the breaker trips this is why people see there lights dim and such when other applicances , or "really big amps" are in use , if your amplifiers are receiving less than the required 120v at the wall they also lose substantial output capability

I AM an electrician , have been for 13 years , and there is absolutely bennefit from running 10AWG wire , its called voltage drop. Your amps power ratings assume a steady 120V ac at the wall outlet , the amperage ratings on romex are only good for a certain distance then they drop , #14 wire at a length of 200 ft won't even carry 10 amps let alone 15 , also the guy who said not to run multiple circuits because of ground noise was correct reason being there will be small differences in impedance on each ground run , your equipment will then choose the path of least resistance and hum like crazy. The best thing for you to do is run one dedicated circuit , A 30amp breaker with #10awg wire should suffice if the wire length is under 90 feet , if its over 90 feet up the wire size to #8awg , still on a 30amp breaker ,m the will prevent any voltage drop. Going this route there will be no ground loops , and you will have 3600 watts continuous available for your system. As far as getting the wire on to the receptacle , there are 15 , 20 , and 30 amp rececptacles that accept the proper size wire accordingly. If your run is over 90 feet and you have to go up to #8 , you simply wirenut 3 short pigtails of #10 at the receptacle , problem solved , hope this helps you , mike price