Got around to doing some more testing / listening after everyone vacated the house this morning.
I decided to forgo the earmuffs so that I could listen for straining and clipping better. I turned the sub off and set the receiver to pure direct stereo with the M80’s set to large and LFE to the front.
I put DSOTM back in and gave it a whirl. Although this a great sounded CD, it isn’t very dynamic, or loud. That being said, I was able to pin the volume on the receiver without it shutting down. Peak DB’s were 110. That’s the positive. The negative is it sounded like crap. Sound quality started to go south at -10 db on the volume control which was an average db of 95 with peaks to 100. After around 95, I could noticeably tell that things just sounded strained, not clear and the mids just lost their slam. As I turned the volume up, it just kept getting worse. I didn’t leave it pinned for but a few seconds for fear of long term hearing loss and fear that it was screwing up my drivers. At full volume the average DB was 104 db with this CD. The track I used was “Time” and I didn’t crank it till after all the clocks were done ringing.
After DSOTM, I put in one of my favorite new disks. Carbon Leaf, Indian Summer. I think Mark Johnson would even approve of this disk. It’s mastered well for an Alt Rock type CD. Plus, I just like the music and if I’m going to go deaf listening to something, I want to like it. The second track “What About Everything” has a lot of vocals but also has some pretty dynamic drums and guitar. This track has about an 8 DB range. Not so surprising, it sounded very good till the average db was about 95 with peaks around 103. Clarity and detail just started to fade into a muddled mix of crap and even at this volume; the peaks were starting to loose clarity and slam. I didn’t even try to pin the volume with this CD – what’s the point? Out of morbid curiosity, I still bumped up the volume to where the average was 105 db’s with peaks around 112. This was at a +5 of a max +15 on the control knob. It did not shut down, but again, I did not leave it there for but a few seconds. At no point during any of this foolery did the speakers go into a hard clip. The music just sounds like crap.
Seeing how my ears were already buzzing, I decided to pop this CD in my two channel rig. This one has a Rotel RB 1080 / RC 1070 comb driving a pair of Wharfdale Opus 2’s in a 32’ X 28’ space with vaulted 22’ ceilings. Ya I know, completely different speakers and electronics, but I was still curious. At about 7/8 volume, even though it was very loud (114 – 120 dbs) and it was hard to not wince, sound quality was starting to degrade. I did not try to pin the volume for three reasons 1) sound was degrading 2) it was simply too dam loud 3) my neighbor across the street was giving me a really bizarre look. Now I’m wondering if I need a different amp for this set up another set of M80's because I could pin the volume when I had them in this room.
So for you engineer types, here’s the specs off the Yamaha for you to ponder and speculate over.
AUDIO SECTION
• Minimum RMS Output Power for Front, Center, Surround,
Surround back
20 Hz to 20 kHz, 0.06% THD, 8 Ω ...................................... 90 W
• Dynamic Power (IHF)
Front L/R, 8/6/4/2 Ω ..................................... 120/155/190/235 W
• Maximum Useful Output Power (JEITA)
[Asia, General, China and Korea models]
1 kHz, 10% THD, 6 Ω ....................................................... 130 W
• Maximum Output Power [U.K., Europe and Asia models]
1 kHz, 0.7% THD, 4 Ω ...................................................... 140 W
• Dynamic Headroom
8 Ω ....................................................................................... 1.4 dB
• IEC Output Power [U.K., Europe and Asia models]
Front L/R, 1 kHz, 0.06% THD, 8 Ω ................................... 100 W
• Damping Factor (IHF)
Front L/R, SPEAKERS A, 20 Hz to 20 kHz, 8 Ω
.................................................................................. 120 or more
• Input Sensitivity/Input Impedance
PHONO (MM) ........................................................ 3.5 mV/47 kΩ
CD, etc. ................................................................. 200 mV/47 kΩ
MULTI CH INPUT ............................................... 200 mV/47 kΩ
