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Matt | Hi, I was wondering if someone could help me. Im after a THX Ultra certified preamp but all I seem to find is preamp/amplifiers. I don't need an amplifier as my speakers are active so I don't really want to pay extra for an amp that I won't use. Is having active speakers the wrong way to go about this or is it ok? If so has anyone got any preamp models they could point me to. Thanks |
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G-Man | Depends on the active speaker. In the future I imagine most of the best speakers will be active. It makes the most sense. The designer/engineer can optimize the speakers performance by specially "tuning" the amp for the woofer and then "tuning" one for the midrange and tweeter. Ideally you could have a separate amp for the woofer, the midrange, and the tweeter--thus negating any need for a crossover. And tweeters need little amplification, midranges slightly more, and good woofers a lot. You could customize these perfectly. Of course, the speaker ends of weighing a lot more and in a surround set-up you would need to have an electrical outlet by each speaker, unless you want extension cords running all over the place---that is definitely low WAF (wife acceptance factor). The old Paradigm Reference Active 20 and 40 was one of the best speakers ever made--Probably the Joseph Audio bookshelf speakers were the only ones that could meet or exceed the frequency flatness and response of the Paradigm Active's. The main problem was that people weren't ready for active speakers--they already owned receivers or amps--hence they weren't going to waste money on buying amplification they already had. Currently, all receivers and amps are compromises to each speaker. Thankfully, since most receiver amp sections are so similar it doesn't have enormous effect. But it is less than ideal as any engineer will tell you. The great new NHT 6's have amplified woofers, as do the Def Techs and a number of others. Marantz has an Ultra THX pre-amp listing at $2000. The Aragon is an Ultra 2, the Anthem, Classe, Parasound, Integra, and Arcam to name a few. Of course, all these pre-amps are very pricey. It depends what your budget is and what speakers you have, etc. whether it makes sense to go this route. There are certainly much less expensive pre-amps that are excellent, but not THX Ultra certified. |
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Matt | Thanks for that, that is pretty helpfull. I had looked at a few you mentioned but as you said they are all pretty pricey. Saying that there are a few amps/receivers that are THX Ultra certified for a resonable price but all these have amps. The Marantz ones also seem to have amps, like the SR9300, but I suppose these have a pre-amp out as well which would be ok wouldn't it? I just thought it would be cheaper and less waste to get one without an amp? $2000 is about the price range I was looking at. At the moment I have a pair of Mackie HR824's http://www.mackie.com/products/hr824/index.html if you fancied a look at them. They have 2 amps in each speaker, 100 watts for the tweater and 150 watts for the mid/sub. They are very nice set of speakers and I would like to build off those if possible. Again, thanks for the help, if you have got anymore advice on my questions above I would really appreciate it. |
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G-Man | The Outlaw Audio 950 av pre-amp, while not THX certified is an excellent piece of equipment and can be bought for about $899. I don't think you will find a sonic advantage in getting a THX pre-amp. THX is mostly useful in setting a consistent reproduction spec for video, audio, and theatres. A good pre-amp can normally be set to these same specifications. You can set the subwoofer crossover to what THX says Look up on the THX web site and see what specs they have on pre-amps--then see if the Outlaw matches it or exceeds it and if the Outlaw can perform the settings that are required to get THX certs. By the way--do you like those Mackie speakers? They seem startling inexpensive for what appears to be an amazingly flat response. I am amazed they haven't been reviewed in major publications. |
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Matt | Again, thanks for the help! I love the Mackie speakers, they are regarded in the world of audio production to be the best audio monitor around that price range by far. They are better then a lot of monitors 5 times their price. I basically got them to make music with and then had the idea to use them for a home cinema setup as they were THX certified. You also receieve a print out of the frequency response for each individual speaker. The sound technicians have to get it flat enough to pass the THX standard, then they print you off your own speakers graph! Nice touch. Shame they don't make diapoles as well, I would be laughing. The 950 watt 15" sub looks like it is a nice piece of kit as well but I think the 12" will do me! Im sure the Outlaw is a superb pre-amp, I was just looking to get it all THX certified. But as you say, if you can reproduce similar results for a quarter of the price it might be worth it. Is it possible to get one of the Marantz amps, like the SR9300 or AV9000 and use the pre-amp outs on that though? |
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Matt | Just checked up about the Outlaw 950 and they don't do a CE approved version. As I live in the UK that isn't an option at the moment which is a shame. |
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| Re feeding HR824 from receiver preamp outputs: yes, it's possible. HR824 even has unbalanced (RCA) connection. One problem though: the use of longer (10-30', i.e. 3, 10 meters at most) unbalanced cables is not recommended because they'll almost inevitably will pick up a lot of noise, especially 50Hz hum. There are quite a few ways to convert unbalanced inputs to balanced or insulate inputs from the noise. First method is to buy high-end audio transformer / direct box from www.jensen-transformers.com (tranformer + your case, wiring, etc. will cost you $40-$100 per speaker, ready-to-go direct box about $100 per speaker). They're simply the best -- +0-0.01db frequency response from 20Hz to 20KHz (freq. resp. goes down to -3db at 15Hz and 15MHz or so), no phase shift, they're passive [no power required], they electrically spearate inputs and outputs, etc. etc. etc. Second method is converting unbalanced outputs to balanced by, essentially, messing up with your receiver which I will not recommend until you feel confortable working with large PCB you see for the first time in your life. And there are few ways in between -- e.g. try connecting via unbalanced first: who knows, it may work! Alternatively, Behringer makes MMX-882 6+2-channel unbalanced->balanced converter for $80 (though rated freq. response is +-3db from 5Hz to 200KHz; theoretically it should do much better in the range I am interested in -- i.e. 30-20,000 -- but Behringer keeps silence about MMX-882 in meaningful freq. range). There are also direct boxes from Rane (see www.Rane.com) -- passive transformer +-2db [about $100/channel], Aphex AP124A -- active servo balance +0-0.5db [about $100/channel], and there are two or three manufacturers who do them for $100-$200 per channel but nobody beats Jensen in terms of performance (c'mon, Jensen's is plain transparent) or Behringer in terms of price. BTW, there are lots of app notes, white papers, etc. on www.jensen-transformers.com about wiring, grounding, going from unbalanced to balanced and back, -- worth reading. I do not for any of the guys mentioned above. Thank you, Andrew ps: one more caution. You'd better buy cable in bulk and solder cables yourself (not a rocket surgery indeed). I recommend high-quality low-gauge 2-wire shielded cable. Remember that when it comes to audio resistance is primary, shielding is secondary. Belden 8760 (18ga) is overall the best, 8762 (22ga), 8761 (24 ga) are little bit worth; Belden 8712 (16 ga) would be the best but it's too thick for most jacks. It costs nothing -- $50-60 per 250' (75 m) reel. Horizon Lo-Z4 or, better, Lo-Z5 will work too. And there are many more cable manufacturers that do decent cables. Good luck! |
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| I too have the Mackie 824 speakers (along with the Mackie 12 inch subwoofer). They sound absolutely perfect (I got hooked on them when I spent some time at RealWorld studios, where all their albums are mixed using Mackie 824s). I was originally driving them from a Mackie mixer, but when I got a video projector I wanted to do surround sound. I tried to find a preamp, but finally gave up and bought a Kenwood receiver. Due to their popularity, receivers are just way cheaper than tuner-preamps. Using the Kenwood has the added advantage that I use the built-in amp to drive the center and surround channels (using un-powered speakers). I use the balanced inputs on the Mackie speakers. Hooking it up to an (unbalanced) RCA jack was no problem at all. I went to a local music store (not audio store) and got the right cables. You can also find them online. So far, so good, but the problem is that when I hook up different video sources it is a pain. My DVD player is component, VHS is just composite, and I also drive it from several computers (HD15). The Kenwood does not convert between different video formats (composite, S-video, component), so I end up playing with several different remotes, switching inputs. I even have an outboard switch box to switch between computer video. Grrrr. So now I'm looking for a control center (I don't care if it is a receiver or a tuner-preamp) that converts between composite, s-video, and component. Nobody seems to deal with HD15, so I'll just handle that with adaptors (it isn't hard to convert to component). Extra points if it does DVI connections as well, since I expect this will be more popular in the future. I looked at the Outlaw 950, and it does convert between composite and s-video, but not to or from component. Not sure why. |
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G-Man | With a dvd player I connect directly via component outputs directly to the HDTV. I bypass the receiver or preamp. I'd rather have a cleaner direct connection anyway. As I am getting the new Pioneer 59AVi dvd player with HDML--I will have to wait and get an HDTV with HDML---so far i think only the new Pioneer Plasma Elites will have HDML connections, unless you want to get an HDML to DVD-D converter, but that kind of ruins the advantage. With HDML one cable carries the video signal( a la DVI) instead of running 3 cables like component--and the HDML runs up to 8 channel digital from the dvd to the HDTV direct--making the regualr 6 analogue cables unnecessary and totally outperforming them anyway. In 2004 I presume a lot more HDML HDTV's will appear. I wish a new LCOS rear projection would come out with HDML. I will plead with Toshiba:-) |
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sure Unregistered guest | AVM 20 preamp...use the XLR's |
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sure 2 Unregistered guest | http://www.hometheaterhifi.com/volume_8_4/anthem-avm-20-12-2001.html http://www.anthemav.com/NewSitev2.0/Product3.html |
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New member Username: AfahmidPost Number: 1 Registered: Jul-05 | Hi I have 3 set of active speakers. each set conatins 1 speaker with built in amp and the other speakeer without amp but it gets power from the amplified one. How I can connect them to a 5.1 home theater receiver? |