HIGH end 7 channel amp

From my own experience when I expanded from 5.1 to 7.1, I found 7.1 provides a much more enveloping surround environment. I specifically noticed this with movies, as I was disappointed with 5.1 in my room.

I also listen to DVD concerts, and find 7.1 very enveloping for those, but never did a 5.1 versus 7.1 comparison with DVD concerts.

There is potential for 7.1 sources from HD-DVD and BD-DVD. Otherwise, you need DPLIIx and / or Logic 7 to generate 7.1 distinct outputs from normally available source material like 2.0 and 5.1.

DPLIIx / Logic 7 redistribute the surround information across 4 surrounds verus 2 surrounds for 7.1 versus 5.1. With 4 suround speakers, you can have sounds intended to be heard to the side come from the side, sounds intended to be heard from the rear come from the rear, and various combinations. Its pretty hard to do that with only 2 surround speakers as they can't be in two places at once.

I don't think room size is an issue in deciding on 5.1 versus 7.1. My room is relatively small at 13' x 17' x 9.5', and 7.1 works very well.

However, room layout can be a factor. If your seating is against the back wall for example, then 7.1 is not a good choice. If you look at Dolby's recommended speaker layout for a 7.1 listening array, the rears should be behind the listening area and spaced about + and - 160 deg from top center (sides should be + and - 90 degress). If you don't have room to place the rear speakers behind the listening position, spaced out along the back wall, then 7.1 is not a good choice.

Thanks
Bruce

Madhf, I think you have a valid point. Though I would say I did get some decent results going up to 7.1

It was not night and day, but I did notice more of a larger, enveloping surround sound. My system stayed 5.1 for several months, till I could get some time and install some proper side surrounds. Just as I heard improvments when I could finally download prologic IIx from prologic II in my surround processor. It was just a tad more enveloping.

I would say that it does make a bigger difference for active surround movies then any music type concerts.

Just curious: Have you auditioned a good 5.1 vs a good 7.1? I have and am not impressed with the 7.1. To me, it just does not add anything. I do have to qualify that I'm into music video concerts not really into movies. I can say for movies (eg Twister, Jurassiac Park, etc) my 5.1 (rear speakers, not sides)rig sounds better than the local cinemas! Only my 2 cents

Frank,

When I run surround with the two side and two back speakers, I will get (depending on recording of course) different sounds from the rear/side left and rear/side right. From what I have noticed, what differintiates the rear to side is more of a delay type thing to give the effect of more bigger and enveloping surround. I thought of it as what dolby surround was with traditional two channel recorded movies. This is of course if its the traditional 5.1, cause the rare 6.1 is a different ballgame. Of course, I could be wrong in that thinking.

Back to the forum topic, a seperate two channel or 3 mono blocks for the front channels would be my prefered way of amplifing, but that often requires much space. I have one shelf set aside for 1 amp, thus a 7 channel.

Freemand- "Then theres the many companys that make 6 channel amps??? Are not all procesors 5.1 or 7.1. I don't get that but thats for another discussion."

From everything I've read, the two "Back-L/R" chnls are the exact same signal (6.1) with larger rooms potentially benefiting from two "back" speakers instead of one (7.1).

Regarding Mnnc's sugestion, many feel that the two "main" front speakers benefit from having their own 2-chnl amp, minimizing taxation from all the "effect" chnls. Those uninterested in multi-chnl "audio" (SACD, etc), may opt for even higher quality "stereo" amps to drive "premium" front speakers during 2-chnl listening only. Their are other topics you can search regarding all "mono-block" application, three "stereo" amps, two "3-chnl" amps, etc.

Several options out there other than single chassis.

Good luck,

Frank

Mnnc, I just checked on the Halo, and it don't look like they have a 7 channel,

Boy, what an intersting day.I spent over half the afternoon at Hi fi sound in downtown Minneapolis.

I have narrowed the Mcintosh mc207 as one of the posibilities if I did not keep the Gemstone. I brought my Gemstone into the to store to a/b it against the Mcintosh mc207 to have a reference point. I spent about an hour each with both amps and listened to the same tracks from 3 different cds. The system consisted of Vienna acoustics top line speakers, a 5 thousand dollar cd player and a Mcintosh preamp.

I hate to use terminalogy like this but the Gemstone smoked the Mcintosh. I really had a hard time getting into this amp. It did not have the detail and resolution. The bass is good on the Mcintosh. I believe part of what was up with the amp is it may not be the fastest amp where the Gemstone is fast. Things sounded muddy and clouded. Not knowing the system I did not think it was the amp, but system as a whole.

I was wrong when the Gemstone was installed. All of the sudden I heard detail and clarity within the system and of course...music. The bass is where this amp is king...perhaps one of the very top 7 channel amps anywhere in this department. Its so authoratative and detailed in the bass notes. So thats why I wont say the Mcintosh had sub par bass, it just went up agaist Mike Tyson in his prime. The Gemstone had a better and extended airy treble. I have had people tell me the Mcintosh is rolled off in the highs and perhaps thats the part of its issues.

The crazy thing is in all this is the Gemstone retails at $2800, and the Mcintosh retails for $8000. Don't let price fool you...thats what I am learning. I guess Mac like most big names have so many costs with advertising and the middleman, but I guess in the end It comes down to us paying for it all. I may see about getting a different Gemstone amp in case the issue is isolated to the one I have, cause I am more motivated now to keep this thing!

As a sidenote,I heard for the money the ati amps are nice. I thought I heard that its similar to parasound.

NAD M25 - It's their Masters Series 7 channels @160watts each and the sound is beautiful. It's the best thing they've ever done - replaced my Cary Cinema 5 which I loved, and it's better.

How about Halo? Considered the a51/a21 combo?

I actually still have my 5 channel sunfire. Good amp, and I needed the more warm laid back sound at one point but I have done a lot to my system and need something with more detail.

Davemitchell, I am glad you brought up the AR amp. That has been one also that may be decent. My Issue with AR on the amp is they have it priced way too high, or so it seems. $10,000!!!!!!!!!

I checked a little on the Axiom amp, and see its digital. I have to research to understand what that all means in laymans terms. Not sure of the pros and cons of that.

If I dont quickly get the Gemstone to work in my setup I am coming down to Ead 7300 or maybe a Mcintosh mc207. The Mac has the new dynamic power manager and sounds like their best sound multi yet. Anyone have experience with those two amps?

Audio Research 150M.7

Sunfire Audio makes a 7 channel amp.

Musicman, I would agree that Steve and Gemstone would rather see the amp be a perfect fit. (like child adoption!!)

Yes I do have xlr's. The speaker connectors and interconnects unfortunatly above and below one another does not help. They are all criss crossed. I tried bypassing the BPT 3.5 and also brough my Hydra back in with same results.

I also brought my previous amps in and tried them to see if the same effect would happen...it did

I am going to keep playing.

Freemand I assume you've tried using XLR connections if possible with your pre. Keeping the power cords away from the cables, checked your power quality, or used or quit using a power cleaner device. Have you tried a different processor? Digital cable or sat boxes are notorius causes.
Really just a chore though of stripping down to the basics and working backwards through the system to isolate the problem. Remember to actually remove components when testing, still connected in any way can be enough to cause a loop.

I haven't just heard a Gemstone I bought one. I don't see a point in paying 6k+ to get something that may not be any better than this one for well under $3k. I talked with Steve on the phone - he called me, wanting to make sure this was the right amp for me - for almost an hour the day I gave him my credit card info. We had exchanged emails prior to this. Not the quickest responses ever and often get voice mail but these guys will advise to get something else if they think it's in your best interest.

http://tinyurl.com/2j6s7q Audioholics blurb on the new Axiom Amp...courtesy Google cache.

Sounds interesting, lots of power, Class D, one transformer, no idea how it will sound but it won't lack for power.

Holenneck, I could not find anything written yet on the axiom. You know a site with info?

axiom is planning to release a very powerful 7 channel digital amp. keep your eyes peeled

Musicman, you had the bennefit of hearing a Gemstone! It is very natual and smooth to my hears. I like that the highs and female voices have no harshness or ear fatigue.

Thats why I have been playing with interconnects, speakercables arangment etc. to try to get rid of the problem of the hum I am getting. Others seem to be using it to good effect. Seems like it may be my system and or room?

Anyway, the sim is comparable though I am curious about their big boy the titan. It's built quite different then the Aurora.

I agree the Gemstone Blue Diamond 200x7 is one of the top amps on the market and sells for a lot less than some other models including the fairly similar Sim Audio. The Gemstone is neutral as an amp should be, but may not be to the taste of individuals that prefer a warmer or colored sound.

Nealrm,

I have a pair of highly modded kef ref 104/2, Vienna acoustics maestro center, kef ref 102 and kef ref 103 in surrounds, Gemstone 7 channel amp, modded avm 20, modded BPT signature 3.5, and modded arcam dv78.

I love the sound of what I have now. It seems to do most things right for an HT setup.

The Gemstone is awesome amp and will compare to the best out there, though its creating a bit of a hum in my system.

Steve at Gemstone is giving me a bit more time with it to see if I can alleviate it.

Thanks...

Can't say whether or not the amp by itself has an "airy top end". I have the amp hooked to a pair of JMLabs Diva Utopia Be's. Set up properly, I have not heard a system that can beat it for the same price. I can say that I have not heard any limitations in my amp/speaker combo, thereby no limitations in the amp, so far. At only 175W per channel, power hungry speakers might not fare as well, but you mention that you have efficient speakers so I doubt that will be a problem. What is the rest of your system?? I looked at Rotel, Krell, Linn and each time I came back to the Arcam. Just sounded more musical.

My advise is to try the amp in your system if possible. Won't know whether or not it sounds good with the rest of your equipment unless you do. See if the dealer will let you borrow it for a night or two.

Nealrm, I have been wondering about the arcam. I do Have a arcam dealer here so I can practically try that one out. Does the arcam have an airy top end?

I have effecient speakers so power is not an issue.

Moremoneythansense....intersting name. You must have more money then you know what to do with so buy audio. I wish I could use more then one amp. I recently had a three and five channel in my system but need the extra shelf, thus one 7 channel.

The 7 monoblocks in the rack would be my dream system.

5 channel amp + 2 channel amp = 7 channels with two power supplys rather than one.

Look at the REALLY high end gear; there is a reason that they have 2 channel power amps with SIX chasis.
If, as stated in your post, you do want the "best", why not go with seven mono-blocks? Seven really good amplifiers sharing a one power supply is limited.

I have the Arcam FMJ P7 and am quite pleased. Very warm possibly at the expense of some accuracy, but would rather enjoy the music than listen for flaws in the recordings. Amp choice will depend on the rest of your equipment. May need a bigger amp if your speakers are power hungry. With 2-channel music the P7 acts as two monoblocks producing very nice sound.