Members hemismith Posted March 27, 2011 Members Share Posted March 27, 2011 We are thinking of starting up the band again in which case I would need to buy a sub. I'm also simultaneously setting up a home theater system. Could I use a PRX sub as a home theater sub (and thereby save a little money)? Link to comment Share on other sites More sharing options...
Members GCDEF Posted March 28, 2011 Members Share Posted March 28, 2011 I don't have a definitive answer except to say that generally HT subs need to go lower. The THX spec calls for 20hz I believe. Most Live Sound subs don't do much below about 40hz. The automatic on and off feature that most of them is pretty convenient. So, it would probably work, but not be as ideal as a good sub designed for HT. Link to comment Share on other sites More sharing options...
Members six20aus Posted March 28, 2011 Members Share Posted March 28, 2011 I watched a movie the other day with my RCF 4pro 8003 and lets just say - I thought I was as the movies.... HT subs do go lower but I suspect the difference isnt that noticeable.... Link to comment Share on other sites More sharing options...
Members tuchan Posted March 28, 2011 Members Share Posted March 28, 2011 Yeah they do need to go very low. I did this a while back with a 15" pro audio sub. It did work but I needed to set it up correctly which took a little time. Filtering needs to be off on the amp. I needed to boost around 30Hz to get the low end and ran nothing over about 60Hz out of it. Much more then it would loose theater feel and start getting noisy. Placement of the sub was also interesting. I ended up with the speaker and ports facing the floor suspended on a small stand I made up from some wood only about an inch. I was getting port noise and having the sub facing the ground minimized it. The sub was also placed in the center of the room under the projector screen. Closer to the middle of the room the sound is clearer, in a corner there is more of a bass effect but the sacrifice was boom. It will work and you must experiment to get results. I ended up just getting a high quality Energy sub. It is clearer, powered and sounds better. When you flog it very hard it does not compete with the outright grunt of pro audio gear. But for a better sound, buying a intended for use product really is the best bet. Using pro audio gear and doing this you will find out which cabinets are built well compared to others, hearing the cabinet leaking and creaking under the pressure is very apparent when watching something with a almost constant very low rumble, like a space type movie for instance. I would like to hear how you go doing this, report back please. Link to comment Share on other sites More sharing options...
Members TimmyP Posted March 28, 2011 Members Share Posted March 28, 2011 I've yet to hear a pro sub that I'd want to use for HT or to augment my Hi-Fi. They don't go low enough, and the sound is not clean enough. Regrettably, I don't have any recommendations that are affordable. (http://www.danleysoundlabs.com/pdf/DTS%2010%20spec%20sheet.pdf http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=TH%20SPUD) Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 28, 2011 Members Share Posted March 28, 2011 It will work just fine, and in fact will probably work better than most home theatre subs. What do you guys thing we install in real theatres? Cinema versions of pro audio subs. The Cinema version of the 4718 is probably the most common sub in the cinema industry. I serviced for a chain that had several hundred of them. If you have some eq available, there is some that may benefit you but maybe not. Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 28, 2011 Members Share Posted March 28, 2011 They don't go low enough, and the sound is not clean enough. Regrettably, I don't have any recommendations that are affordable. Where do you get this stuff from? I just finished a (real as in 35mm and D-Cinema) screening room for a client that seats 12 and used SRX-712's for L/C/R and a 718 for sub, controls for surrounds and a CP-650 processor and the installation meets THX standards for certification (though the client has no need to feed that corporate machine). The low end is impressive and plenty low. Link to comment Share on other sites More sharing options...
Members soul-x Posted March 28, 2011 Members Share Posted March 28, 2011 Will the input sensitivity on a PRX618 let the -10db signal in your average home receiver to drive it significantly? I could look it up but I am feeling lazy. Link to comment Share on other sites More sharing options...
Members hemismith Posted March 28, 2011 Author Members Share Posted March 28, 2011 Thanks everyone, excellent info. Wow, that Danley is quite something. I saw a similar huge passive sealed-box dual woofer THX-certified JBL or Infinity home sub once at the Harman outlet years ago. I guess I'll see how the band pans out -- should know this week or next -- and if that does I'll try it out first and see. Link to comment Share on other sites More sharing options...
Members hemismith Posted March 28, 2011 Author Members Share Posted March 28, 2011 Will the input sensitivity on a PRX618 let the -10db signal in your average home receiver to drive it significantly? Good point. My thought is that there will be more than enough headroom to compensate, but I'll keep that in mind. Link to comment Share on other sites More sharing options...
Members drumstix Posted March 28, 2011 Members Share Posted March 28, 2011 Shoot for the PRX-XLF sub. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted March 28, 2011 Members Share Posted March 28, 2011 Will the input sensitivity on a PRX618 let the -10db signal in your average home receiver to drive it significantly?I'd guess you'd want the sub at least -14db down from full boogie anyways unless you want to hurt yourself . Link to comment Share on other sites More sharing options...
Members soul-x Posted March 28, 2011 Members Share Posted March 28, 2011 I'd guess you'd want the sub at least -14db down from full boogie anyways unless you want to hurt yourself . Yeah but, at that point SNR would come into play. So, let's pretend you underdrive it by 14 db and that it can't produce more input gain -- you've got what -- a 40 watt sub that is noisy, very large (8 cu ft?) and has poor extension. What does a big, crappy, noisy, poor performing sub cost for home audio guys? I think my little 8" Yamaha powered home sub cost 40 bucks. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted March 28, 2011 Members Share Posted March 28, 2011 -- a 40 watt sub that is noisy, very large (8 cu ft?) and has poor extension.You've obviously never heard a PRX618XLF . Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 28, 2011 Members Share Posted March 28, 2011 Shouldn't be a problem driving the PRX with the output of a quality AVB receiver, many of them will drive +4dBu ok, though won't drive +26dBu MOL. Worth checking out the spec's however. I think you can get rated SPL out of the PRX with roughly -4dBu on the 1/4", and there is a trick that can be used to gain another 6dB of sensitivity if the bal input is not already servo'd. Link to comment Share on other sites More sharing options...
Members Zeromus-X Posted March 29, 2011 Members Share Posted March 29, 2011 I've always said that if I can't get enough work with my Meyers, I'd love to set them up as a home theater system here. Two UPA-1C's up front, two USW-1s hidden in the false fireplace, Buttkickers under the couch to boost it that little bit more. I'm sure the people who live upstairs would love it, too. It'd turn their whole floor into a vibrating massager. Link to comment Share on other sites More sharing options...
Members Bugzie Posted March 29, 2011 Members Share Posted March 29, 2011 I have an extra Proel Flash 15 sitting here and I was thinking a ART cleanbox would work to get the -10db signal up to a +4db. Andy, your thoughts? Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 29, 2011 Members Share Posted March 29, 2011 I have an extra Proel Flash 15 sitting here and I was thinking a ART cleanbox would work to get the -10db signal up to a +4db. Andy, your thoughts? Try it without first. I suspect you will not have any problem. Link to comment Share on other sites More sharing options...
Members imnotded Posted March 29, 2011 Members Share Posted March 29, 2011 Correct me if I am wrong, but most pro audio subs can go down to 20Hz, they just cant reproduce those frequencies "loudly" without damage. I doubt anyone would have the sub turned up that loud to where it would be a problem. Am I wrong? Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 29, 2011 Members Share Posted March 29, 2011 Correct me if I am wrong, but most pro audio subs can go down to 20Hz, they just cant reproduce those frequencies "loudly" without damage. I doubt anyone would have the sub turned up that loud to where it would be a problem. Am I wrong? You are exactly right. Also, in home theatre the 20Hz spec so causally bandied about is not a -3dB spec but at best a -10dB spec. and often is hedged with 1/4-space loading. Efficiency of a true 20Hz, -3dB subwoofer of reasonable size would be very, very low and distortion very high due to the need for exceedingly high displacement of the smaller drivers typically found in home theatre packages. IIRC, the THX LF response spec is nowhere near even 30Hz at -3dB, and that can be obtained from several pro audio subs with properly applied processing and derating of the speaker. Something tells me that 35Hz at -10dB is the target for a sub receiving THX certification (for professional cinema applications). Link to comment Share on other sites More sharing options...
Members hemismith Posted March 31, 2011 Author Members Share Posted March 31, 2011 The THX sub spec I found on their web site is -6 db at 20 Hz; I don't know if it's the same for home and pro though. THX-certified subs used to be pretty uncommon;I'm somewhat skeptical of the specs on the many small and cheap subs out there now. But home theaters don't have near the volume demands of pro audio equipment, so it's certainly a bit easier. I'm not too concerned with the really low stuff though, and my wife doesn't like it, so I'd be happy if I got good response down to 35 Hz. Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 31, 2011 Members Share Posted March 31, 2011 All my references to THX is for the real cinema certification program. There vis no requirement that a cinema sub go down that low. The most common THX certified cinema speakers of all times are the JBL 4600 series (much the same as the 4700 series, different hardware and cosmetics) and the screen array series. Those are the cinema industry's "gold standard". That's what the product is mixed on for general theatrical release material. I'm sure Todd can add to this. Link to comment Share on other sites More sharing options...
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