Axiom Home Page Forums General Discussion Home Theater Harsh sound at reference level

Just set up my brother's home theater. We watched LOTR Two Towers last night and it sounds great, except at a few points in the movie, the audio got harsh. It was usually during very loud action sequences. It was actually kinda painful to listen to. Every other time it sounded fantastic.

Is this my receiver clipping?

We were listening at -6db

Axiom VP180
2 Axiom M60v3
4 Axiom QS8
1 SVS PB13 Ultra
NAD 765 receiver - rated at only 80W per channel. But I figured they probably underrate it a bit.

It's a pretty big theater.


More pictures
http://s663.photobucket.com/albums/uu353/jinrsvl/Silverwood%20Theater/

Sounds like it could very well be clipping.

Yes. "Harshness" from the speakers like you are describing during those dynamic peaks is a sign your receiver is not capable of powering your speakers in your room. This in undoubtedly the cause. You would definitely benefit from an external amp. Since you run a VP180 and it will dip below 4 ohms at some frequencies I would highly recommend getting an external amp for the front 3 speakers (M60 and VP180). Does your receiver have pre-outs?

It came on pretty suddenly. It sounded great...then, a big clash of swords and the thing turned into a mess. It was mostly high pitched harshness. At the time we were worried about it being the speakers breaking up at high volumes, but then I looked up the specs on his receiver and saw it was only 80W per channel and he is using all 7 channels.

We originally got the components thinking that he would be using a VP150, but when Axiom came out with the VP180 we had to have it. So, we ordered one and Axiom was nice enough to take back the VP150.

On a side note, we also ordered a EP800 to replace the SVS sub we had just got. The SVS turned out to be a little too tall and the EP800 on its side was quite compact (relatively at least). The EP800 arrived and it was busted. The drivers seemed to be fighting each other and there was a massive hum from it. It put out very little bass. We went back to the SVS and made it work.

Would this work? Yes, he has preouts. It is one of those receivers with the replaceable blades, so he might even be able to get balanced outputs.

http://www.emotiva.com/xpa3.shtm

I bet that poor receiver was running really hot (temperature wise) as well. Surprised your receiver has never shut down. I would be careful running that receiver at reference levels in that large room like that again and monitor the temps. That distortion sounds nasty.

That's a beautiful theatre!

It looks like you've got plenty of room to fill there, judging by the height of the ceiling, I'm sure you'd benefit from an external amp, esp at the levels your pushing.

Looks like you have 7.2 pre-outs, so you're in luck.

Yes, that would do the trick.

Wow, that is one sharp looking theater!

You didn't try having axiom correct the problem with the ep800 and you just sent it back without a replacement?

Too bad I screwed up and didn't have him order the right receiver. He's working with a local audio guy that is also recommending parts and this amp was his choice, not mine. I was recommending the Onkyo 807 which is THX II certified. My brother really wanted to be able to adjust the center and sub volume on the fly since he says in other systems he's heard he has trouble hearing the dialog. The NAD has buttons to control the sub and center channel levels on the fly, and it returns to the calibrated setting after power down.

We're kinda bummed about the sub too. It came in and was busted. A QS8 also had a busted driver. Two bad Axiom speakers and I'm starting to look like I don't know what I'm talking about.

I tried to get him to get a replacement. Since his theater is a pretty impressive room and going all Axiom was cool. But, he already had the SVS and got it set up before I got there.

His audio guy that is helping him (I'm 130 miles away) even thinks the SVS is a little sloppy and I thought the EP800 might be a little tighter, but after getting two dead speakers from Axiom I'm afraid he's a little turned off on them right now. It really sucks to have to pack up a EP800 and send it back. They weigh a TON!

I was also hoping to get the SVS PB13 Ultra for a discount...so that might have influenced my opinion on trying to get the Axiom sub fixed

That sucks about the bad EP800 and QS8. Was it shipping damage or what?

The box on the EP800 was mangled a bit. But the speaker was intact with no damage to the enclosure. I don't know about the QS8. When you push the 5" driver it makes a scraping sound. Axiom sent out a replacement driver which is very nice of them.

I didn't get a chance to play with the bad EP800. I thought the buzzing was just a ground loop but his audio guy fiddled with the settings and tried other outlets and it still buzzed. The phenomenon he described sounded like one of the drivers was disconnected and was passively radiating, or one of them was wired opposite. When I looked at it it was beautiful and I wanted one, but it would never fit in my room. And my family room is not acoustically sealed like his theater is.

Amazingly beautiful room.

Hope you didn't fry any speakers by driving that loud distortion through them.

I agree with others about getting external amplification for the front L/C/R.

Incredible pictures of the build. Love all that custom stuff on the walls and the ceiling is ridiculously cool.

Sorry to hear the final pieces aren't coming together as smoothly as one would hope. That said, the room seems like a big enough investment that your brother should take his time (and it looks like a little bit money, unfortunately) to get it right.

Post some more pics of the final set up with speakers, etc. I really want to see it in its completed state.

It looks better in person where the lighting is much darker than in the pictures. You don't notice the texture on the wall as much, and the ceiling glows a dim blue. It's like watching a movie at dusk. It is really cool. The blue glow decreases the overall contrast of the movie a tiny bit, but the effect is cool enough that it is a good trade off.

I don't think it distorted enough to damage anything. It sounded great during every other moment. We turned it down a bit after noticing the distortion, but the center volume was a bit low. I considered using Dynamic Range Compression on the BD player a bit to bring the dialog volume up and the distortion down, but we just lived with it at a bit lower volume.

I was impressed more than I thought I would be. I've never heard a sub hit that hard before. I could feel it in my chest vibrating my insides. My SVS PB12-NSD never hit that hard.

You would be surprised at how inexpensive the room design was. It was a hefty chunk of money, but you can buy a projector for more than the price of the room. We tried to do the whole thing on a relative budget. We saved a lot of money here and there. Axioms are great speakers but relatively inexpensive. The NAD is the only mistake we've made so far, and that can be fixed with a $600 amp. We tried to get away with the budget NAD and it got us. It's still a great receiver. If that's the only problem we have, then we're in good shape.

HA, that's the very room I posted about the other day in the water cooler and whenever I read Peter's comment about it needing M80s that was the first thought that hit my mind also. I noticed the VP150 and didn't think much about power requirements but with a VP180 I'll certainly agree with the masses regarding the need of a more robust amplifier even if you are running the 8 ohm M60s.

Beautiful room, sorry to hear about the bent Axiom speakers.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=325421#Post325421

If you read the thread on AVS, I thought he was going to hide the speakers more than he did. I was hoping he would build the corners of the room to contain the in cabinet m60s. That's why I recommended the m60s. Now since the light from the projector reflects off the speaker he's going to have to wrap the speaker in cloth somehow. Mario's got a plan to hide everything a little better than it is now. I don't argue with Mario. He's got that woodworking figured out.

We couldn't find a place to hide more than 1 subwoofer the size of a baby hippo. 1 sounds pretty good to me...

That man must be 'Super Mario' from the looks of his handiwork!

You know another possibility if budget is a concern is to maybe check out an Outlaw Audio M2200 Monoblock for the VP180 and add a couple more later for the mains. My thoughts are that by taking care of the power needs of the VP180 in that system it will take a huge load off of the NAD, and the NAD will probably run the M60 mains and surrounds just fine ... only my thoughts!

Outlaw Audio Model 2200

That was another option I was considering, but would it be better to run the VP180 on a monoblock, or to run the m60s on a two channel amp?

I was thinking it was the VP180 that is the odd man out of all the speakers so it made sense to run it on a monoblock amp. But, if I ran it on a different amp, would it sound different then the m60s?

If you are talking about running the VP180 on the 80wpc NAD and get a 2ch amp for the M60s, I'd most definitely get a single monoblock for the 4ohm VP180. IMO with that system the VP180 is what needs to be mindful whenever considering power, the 60s and the QS8s are an easy drive and I think the NAD at 80wpc will drive them just fine.

Since it is the dynamic peaks which are causing the problem, the power requirements of the M60's are probably exceeding much greater than 80 watts of power in those instances as well. The safer purchase would be to get external amplification for the front 3.IMO you might be still at risk of damaging your speakers or receiver just going with external amplification with the centre if you continue with those same volume levels.

The Outlaw amp is some really nice gear.

Where the heck is Wid?

Rotel.

Here's an iphone photo of the Axioms across the front. Remember that the EP800 is dead and was replaced with the SVS PB13 Ultra he already had on hand, so this is an old photo he sent me as a teaser. More photos will come later.

A nice Rotel amp would do the trick, that's for sure.

I would go with an A1400-8

Did you have any discussion regarding the ep800 with axiom at all? I wonder if it was shipping problems or a manufacturing defect.

All my info is second hand. I don't know much about the problem. When I find out I'll let you know.

Yes, packing up an EP800 sucks big time. I just packed mine and it goes back tomorrow after only two weeks. It worked fine for a few days but then if you turned up the base near the half-way point it sounded like there was a squirrel in the speaker trying to get out. Just a very weird and loud slapping sound. And yes, the box it came in was totally destroyed. It comes packed in two boxes - the outside box being the one that was destroyed. Those delivery guys sure do a number on these speakers.

Anyhow, I'll just keep my EP-500 and avoid future hassles. I'm fed up with FedEx.

Rick, I've never seen you promoting Rotel.....why?

NAD rates their amps very conservatively, they always have. This is probably why it didn’t catch on fire, just kidding (I think). I suspect if you had a Yamaha or Sony receiver we would be having a different conversation right now.

Like others here have said, I would at least get a 3 channel 4 ohm stable power amp for the front rating minimum 200 wps into 4 ohms. That should give you lots of head room for those times you really want to make those Axioms sing and not have to worry about speaker damage. I would recommend an amp that has a toroidal power supply for added stability.

To keep the price down you might want to look at some professional amps. I use an AudioTrak 6 channel 4 ohm stable pro amp rated at 300 plus wps. In my 4000 cubic foot room, my hearing will go before I damage any speakers. I don’t get any amp clipping even at 105 db at my seating position. (BTW, 105 db is damn loud!)

http://www.audiotrak.com/pdfs/AT-6100-Amp.pdf


Wonderful room buy the way!!!!!

Autoboy, that is now my favorite all-time home theater room.
It is just so full of detail, so incredibly perfectly and tastefully put together.

What has happened to Axiom quality control? Doesn't it seem that the flagship Axiom subwoofers are having more than their share of problems?

I have an SVS sub and have no problem recommending them. However, if I were starting over, I'd pick up a pair of the Epik Legend subwoofers for substantially less than one of the big EPs.

I think the Onkyo 807 would have been a good choice. I like to go with a stack of used 2 channel amps for my main HT system. I recommend the Yamaha M80/M85 Monster amps, pure Class A for the first 30 watts, AB after that. These are stable down to 2 ohm loads and rated at 330 Watts Continuous Power per channel 20Hz-20kHz, 0.02% THD at 4ohms, Dynamic Power, 1kHz at 2 ohms - 850 watts per channel, 640 watts per channel at 4 ohms. These are sweet sounding gentle monsters which are as at home at low volumes as lethal volumes.

I would love to see a stack of 4 of these in an HT system:

Get those meters bouncing!

That is a beautiful amp, love it.

Ain't it something?

a saaaaaaaaaaaaaaweeeeeeeeeeet amp.

do you have the speakers set to small autoboy?

Yes indeed!

Everything is crossed over at 80hz

I'd like to keep the audio components to a reasonable price level. The whole system was done with bang for the buck in mind.

AB, the cause or causes of what you've observed would first have to take into account the actual sound level at which this occurs. -6dB on the receiver doesn't really determine the sound level and an SPL meter should be used to determine the actual level so that some conclusions can be drawn as to whether the receiver or a speaker is inadequate or defective.

Except for the room obviously.

My brother chimed in and says that even after 3 hours of LOTR two towers, the NAD was only slightly warm to the touch.

Does he still have the speaker harshness or has he learned to listen at lower volume levels till he gets an external amp.

I doubt the NAD would ever get hot, they are very well built units.