Axiom Home Page Forums General Discussion Technical Questions Need quick input about amps, interconnects and SQ

I currently have Axiom M60v2s and VP100 center and I need some timely answers to a few questions. I've posted to another forum but sometimes answers from that one are very slow in coming and sometimes not at all so some here may have seen this post elsewhere.

If anyone can help answer a few more questions I think I may pull the trigger later today depending on what those answers are. Again thanks to all that contribute.

I have a Denon 3808 (130W) and am thinking of adding a Sunfire TGA-5200 today. Many reasons but size, cool running, 200W continuous to all channels and quality is the short list.

When using the pre-out section of the Denon hooked up the the 5 channels on the amp does the signal processing work the same as if the Denon was driving the speakers? An example would be that sometimes on certain movies or tv shows the dialog from the center channel is hard to hear so I pop on the onscreen GUI and bump the center from maybe 0 to +3 or +4 for that movie. Would that still work if using the pre out to an amp?

I figure that as of late I do 60% music and 40% HT. When I play music at parties etc. I notice that after playing music loudly for a while the Denon starts to sound "tired" or "fatigued" (someone told me in a different thread that it may just be the "beer" factor). Would using a dedicated 200W per channel all channels driven amp help in that department and in just overall sound quality?

The amp will sit directly on top of the Denon 3808 or vice versa ( I have forced air ventilation) so I won't need long interconnects. Do I just need to get a good set of audio RCA cables? I saw a cable the other day that was 5 ended. It said 3 for composite video and 2 for audio but if they are quality cables would something like that work to connect 5 channels from Denon to Sunfire or is that a bad idea. I don't mind purchasing good cables but I don't want to spend $40 or $50 a cable.

Thanks to all that have answered my somewhat lame questions in the past and to all that contribute here. Timely answers would be much appreciated and very beneficial as I'm looking at purchasing an amp today but if I'm just wasting my money then I wouldn't want to do that.

Edmond,

1) Yes, you can still control channel levels the same when using the Denon as a pre-amp to the new amp.

2) Would using 200W / channel make a big difference? How big is your room and how loud do you typically listen? (in dB if possible) I'm admittedly biased in this department, but I'm skeptical that you're going to notice a big difference going from 130 wpc to 200 wpc. Using a totally back of the napkin estimate, I'd say you're going to be capable of 3-5 dB higher peaks from that increase in power. It gets harder and harder (i.e. requires more and more power) to make small increases in dB levels as you listen louder and louder. If you think you need that slight bump in sound, then maybe the extra $$$ is worth it to you.

3) Cables - yes, the 3 component + 2 audio combo-cable should work fine.

4) General advice: If there is a good return policy on the amp, then buy it and see what you think. A no-risk return makes that idea low risk. However, if it's a one-time deal and you'd be stuck with it, I'd consider spending my money elsewhere.

Jason

Doesn't doubling the power just make for a 3dB increase?

Technically, I can't think of why a well-cooled amp would start off sounding fine at a certain volume and then decrease in sound quality over time when kept at the same volume...unless someone is bumping up the volume a little here and there...

I agree with everything else Jason said regarding cables, etc...but I'm a little hesitant to think that a new amp would make much of a difference unless your were going up to 300-500 watts...

I'm not that familiar with Sunfire, but I quick review of the owners manual for that amp reveals a 0.5% THD. That's 10x the THD of the Denon you have now. A 70W gain from 130W is only about a 1.5db gain. You will not notice that headroom.

I would recommend going for a quality 2 channel power amp rated at least 400W per channel to get a noticeable headroom improvement. Try to get one that is in the 0.07% THD range or better.

I do a lot of multi channel SACD etc. How would adding just 2 channels of 400W affect that?

0.5% THD is negligible and inaudible.
Don't worry about it.

I agree with the advice provided by myrison with one exception. A separate amp will make the peaks smoother at higher volumes as the headroom for separate amps over the all in one receivers is typically much larger.

As for the 'fatigued' sound, i would hazard an educated guess that it is a beer factor (or for that matter a factor of 'new reference'). When listening to a volume for awhile, it may not "sound" as loud as it did when you first turned it on. Adding the beer in there certainly alters the mental perception of it.
There is a friend of mind who actually starts talking louder the more he drinks. He doesn't even realize he's doing it but his wife uses it as a gauge as to when he's done and ready to go.

Even in multichannel, most of the audio is coming from the mains. The surrounds and rears do not get the amount of output that the mains get. 130W/channel for the surrounds is more than adequate, and imo, not contributing at all to the fatiguing sound you are perceiving.

Agreed, but it's still 10x worse than the Denon. Whenever I see numbers like that, it makes me think what corners were cut to get the power rating versus the quality of the amplification.

Of course, it could also make you wonder if Sunfire is just being more honest with their numbers.

Someone else told me also what chesseroo mentioned when I asked about the THD that it was mostly just a number and at all levels mentioned I wouldn't hear it anyway.

From all my research and as far as I can tell the Sunfire is considered a "good" piece of equipment.

If I were to add a 2 channel amp for the mains of around 400W or maybe even some d-sonic 525W would my center channel become lost in the mix. I did have someone tell me that if I went that route I should power all three front channels with the same amount of power but I just don't know about all this stuff, that's why I'm asking.

Thanks again.

Just because and amp is rated higher, does not mean it will play the source louder. I just means there is more headroom. Again, the center will not get the same drive the mains do. Also, if there is an imbalance, it can be adjusted via the pre-amp (which the Denon would be acting as).

True, and after doing a little more research on the unit, it appears to be a high quality amp. I just think for hat price, it's not worth the 1.5db gain. If I were buying, I would concentrate on the mains only for the problem that was posted.

Is this like standing in a hot shower or having a heater blowing on you where after a few minutes you feel you have to make the water hotter or turn up the heat more on the heater Although I've noticed that when I'm drinking beer in the shower the water doens't feel as hot

You got it, just like everything with the human body it adjusts to its environment. Just like after awhile at a rock concert the SPL is no longer a consideration, then you leave and the ringing in your ears is now noticeable, you are experiencing the same effect.

I also agree with everyone else, to noticeably louder than the Denon is capable of, you have to be looking at twice the power to start with, ~300W @8ohm.

When I added an outboard amp to my 3808, I didn’t notice a significant difference. Certainly not one that I would recommend anyone spending money that would be better spent on food for their children or some gift that would get their old lady horny….

Where I notice the most difference is when watching movies during scenes with aggressive dynamic peaks. Some of the action scenes can scare the crap out of folks if I have the volume too high, whereas without the amp, the peaks would just sound loud as hell.

I’m using a B&O Ice Power 5 channel amp. 200 WPC / 8 Ohm. Something like 350 / 4 Ohm. I got it for a heck of a bargain, so I don’t have buyer’s remorse. But if I would have dumped a couple grand on it, I’d be pissed for believing all the power mongers for touting the virtues of more power is better.

I’m not helping much with this indecisive responce am I?

.

Actually I think you did, you helped prove the point about needing much more power than just a 200W amp would give. The added extra dynamics I can believe, as you now have more headroom with the ice amp, but to go much louder would take much more power

Edmond - I'm not sure what kind of a deal you were getting on the Sunfire, but for comparative purposes, here are some links to Crown amps, which Alan from Axiom has recommended as high-quality amps that will have no problems driving any of Axiom's line-up (including the M80s).

All wpc #s into 8 ohms, since you have M60s...

XLS 202D200x2, $299

XLS 402D300x2, $399.

XLS 602D380x2, $499

Note that while these are very affordable amps for the price, one feature they do not have that is a turnoff to many for home theater use is a power trigger that turns them on only when your receiver turns on (and vice versa). There are ways around this limitation, but it is an annoyance that should be kept in mind when comparing to other amps.

Jason

Bobby, reading this now isn't resulting in "quick input", but if you're going to "pull the trigger" maybe it would be better to do it at the firing range rather than on that amp. Your 3808 may have more maximum power capacity than you think(for example, note Hometheater Magazine test showing about 200 watt capability], and also keep in mind that 200 watts would only result in a 1.87dB louder split-second peak than would 130 watts. For example, a peak played at 105dB using 130 watts could play it at 106.87dB using 200 watts; very little difference. Unless you're actually playing material with a very wide dynamic range(e.g., some classical recordings)at extremely high sound levels that require more than the 3808 can output(rather doubtful), getting an amplifier that's rated at 200, or 400, or 800 watts isn't going to make any difference. Unused amplifier headroom is simply that: unused. Maybe the guy who suggested that what was needed wasn't more power, but rather, less beer, had it right.

Those Crown amps look like a great deal but it appears they only have balanced inputs

Would an XLR to RCA adapter work?

That's what I was thinking. A cheap fix, that.

Yes

Ok. I wasn't aware that they made those kind of cables. Wonder if the sound is affected by them?

Something to look at though.

Thanks.

I highly doubt they would degrade the sound.

Specs show that the Crown amp is 19" wide. Wonder if that is the chassis or the faceplate? I've never really looked at Crown amps and definately not heard one. Anyone here able to compare their sound as compared to other amps?

I have no words...

Thanks for that link JohnK. Looks like the 3808 driving all channels doesn't drop as far as I thought it would.

LESS beer?
Now what kind of cockamamie advice is that?

Yeah, I just acted like I didn't even see that one

19" is how wide the faceplate (with "ears") is on rackmount equipment.

One thing that needs to be noted is that most pro power amps have fans that are much louder than in-home users would like.

I noticed that is was talking about heat sinks with cooling fans when I looked at the description and specs and was wondering if the fan noise would be noticable. I need to measur my cabinet, I don't think 19 inches would go inside without removing the door first and the entire width might not hold 19 in.

I think the ears are removeable which would leave you with the usual ~17"

Could you guys/gals help me out with selecting a good HDMI cable. Depending on the price, I might pick up a couple for my buddies holiday gift, but I have no idea what to look for. If it helps, it would be used to hook his PS3 directly to his TV. I was at Monoprice but they have many different types.

Thanks a lot guys and gals

They look like a solid piece in the pictures. I haven't found an actual Crown website yet to get detailed information.

One of the reasons I'm looking to upgrade is that at times after continuous high volume music it starts to sound a little "tired" or "fatigued" and I was thinking that maybe the Denon 3808 while driving 7 channels might be losing it's "umph". Someone on another forum told me that the Axioms are only capable of so much and more power probably won't help at all. On the other hand on this forum I've seen posts where people say that when they increase their power significantly the M60s and M80s really open up and sound great. I guess I can't accept the fact that the M60s being driven with 400W or above from a 2 channel stereo amp wouldn't sound better than being driven by my Denon (which if the specs are correct from one of the above links in a post) driving 7 channels with approximately 115W.

Am I completely wrong in my thinking or as the other guy tells me, that's just all the Axioms can do!

I highly doubt any of the actual components in the system are fatiguing, as the Axioms are capable of handling way more power than you are putting into them and I can't see any reason as to why the Denon would be having trouble pumping out the power, do you find it is getting hot?

What sort of loud volumes are you talking about? As the Denon is capable of ~100db with out any trouble in a small to medium room, 1500-2000sq.ft, my own room. There are many factors in considering the need for more power, listening distance, room volume. etc. I am sure, that adding more power will make them sound better at high volumes, as you may just be running the Denon at its max and a higher powered amp would help, but as was mentioned, to get enough power to make a noticeable difference you will need that 400W/ch amp.

If it starts out sounding good then as the night wears on , starts to sound less loud or detailed, I am inclined to still say it is you, who are fatiguing and have become accustomed to the loudness and then the volume is turned up on the Denon beyond its capabilities.

I can tell you the other night I was listening to multichannel music, 5.1 and then turned on my zone 2 outside, so now Denon is driving 7 channels, and the volume would go down noticably. I turned zone 2 off, volume increased, turn zone 2 back on volume decreases noticably, my wife even noticed it.

Denon isn't getting hot, I have a big slot in the back of the cabinet and a good fan circulating air through the cabinet. I setup the ventilation that way because when the Denon was in the cabinet without the ventilation it would get fairly warm but I've had forced air ventilation almost from the day I purchased it and it is just a few months old.

My room is probably 3500 to 4000 cf. I'm sure that I am probably adjusting to the volume after a while but when I drive 7 channels as mentioned above and I can hear the volume decrease it just seems I need more power. I run it that way alot because when people are over some tend to go outside, especially the smokers as smoking is only allowed outside

Never mind, Crownaudio.com. Duh

Edmond - in that sized room I'd venture to say you might actually benefit from more power as you've got a big space to fill. On top of that, if you like to run it loud like you describe, then maybe a separate amp would improve your experience.

Like others have previously advised, I don't think you'd need anything more than a 2-channel amp to manage the front L+R speakers. The power requirements of the rest of the speakers are quite meager compared to those. (Perhaps with the exception of whatever you are running in Zone 2. I don't believe you've indicated what you're running there...)

To your question re: adapting XLR to RCA, check these out as a $5 solution.

Mark makes a good point on fan noise. I've read quite a bit on these amps in the past (part of my addiction) and the general consensus is that as long as you get one of their newer lines with variable speed fans, fan noise is not reported as problematic. (just to reiterate, this is second hand knowledge based on what I've read). With the older amp models there is also apparently an easy way to modify the fans to make them run more quietly, but that sounds like too much work to me.

Jason

One more negative to consider... the power consumption on these babies is incredible.

The specs indicate that it "draws no more than 90 watts while idle." I realize that's only the equivalent of leaving of leaving ~1 light bulb on 24x7, but still, 90 watts is around 300x more than the 3808 consumes while in standby mode.

You'd definitely want to have the Crown on a triggered power outlet if you could.

Jason

Bobby, your "all channels" comment indicates that you may be giving that more significance than it deserves. Even when all the channels are active from time to time there's almost no situation where they would simultaneously have to output full power. The standard two-channels driven spec required to meet FTC power regulations is probably the most realistic. Audioholics often has commented on the lack of real-world significance of the all channels numbers and only tests with one and two channels driven simultaneously at full power. S&V still includes an all channels test besides one and two channels, but they typically comment when the all channels number is significantly lower that this had no effect in actual multi-channel operation and the unit handled it well.

Cam, your question may have gotten buried in all the amplifier talk. You don't mention what the distance from his PS3 to his TV is and, contrary to most connecting cables, HDMI cables need some consideration of distance in deciding what gauge to get. The most common 28ga cables are said to be fine up to about 15'; longer distances would make it advisable to get a 24ga or even 22ga cable. Assuming that his run is fairly typical, here's a 10' 28ga cable from MonoPrice that should work well and is available in several colors.

It sounds like it is not so much as fatigue but you are just demanding too much from the Denon. I would also consider running a seperate amp for your Zone 2 as well, or insted of, a seperate for the mains. You just feed it from the low level outputs from the Denon, this might help in the noticeable drop in volume/power you noticed fom the Denon. This amp wouldn't have to be as huge/expensive as the one you will need to run the M80s on to get noticeably louder.