2. tech-talk
  3. 161005-2288

How can I establish a reference level?

With now 350+ hours on my new rear end (I hope it is OK to call the new speakers that, given the common use of the expression front end for the source) I am trying to understand gain and how it relates to listening level. The terms reference level, anchor level, gain structure, dB, dBU, crest factor, etc. all form an ill defined blur. My interest is in protecting one of my five senses. No amount of money and equipment swapping will ever reclaim lost hearing! Now with oodles of distortion free headroom I need to be careful.

Specifically -
JBL 4367 - 94 dB, 300W
Benchmark AHB2 in bridged mono 380W
SONY XA5400ES Compact Disc Player

What I find is -24 dB set on the preamp (with 0 dB being no voltage gain or cut with respect to the source signal) is too loud on most recordings - especially Pop and Jazz. On the 1964 SONY Classical recording of Petrushka, Ormandy (SBK 47664) a gain of -24 dB is pretty realistic as it is on many other classical recordings.
Some recordings sound loud no matter what the volume. Take Jimmy Smith with Kenny Burrell (Phono 870267) for example (listening to him now @ -34 dB)
Much of my listening is far-field, though the speakers are only about 6' apart in an open floor plan of about 1200 sq. feet.

The inverse square law relating to how loudness decreases with distance from the source - how is it affected by a stereo pair? Get on axis near-field with the speakers and just try and keep your mouth shut. Awesome!

So I have a new definition of LOUD and I want to be careful and have some consistency.
I feel -24 dB is a good reference level and am wondering how that relates live sound and the recording process.




mikewerner
arion's avatar
arion
156 posts
 
Mike, There really is no direct correlation between the -dB reading on your equipment and the loudness (dB) at your listening position. The levels set during the recording process are all over the map. There are many factors along the audio chain that also affect the final volume.
The audio industry typically measures at one meter as a standard. I suggest that you measure at your listening positions. Room gain varies. The loudness measured at one meter will be considerably louder than at three meters or at your listening position.
tomic601's avatar
tomic601
12,838 posts
 
The RS meter is robust, durable and pretty accurate- use it as many here have directed.learn to read both the fast and slow for peak and average. Yes the average drives most hearing damage. The OSHA standard may sound conservative but I know and worked w many coworkers who might beg to differ - now.... they may have contributed, but hey we all know better than the scientists....

congrats on your system, enjoy !!!!!
mikewerner OP
119 posts
 

ADDENDUM:

After listening to a lot of music these past few months, I believe that -17dB as set on the preamp is closer to a true reference level.

Lots of music is really loud! I mean how many times can you listen to, say, Aretha singing RESPECT at a realistic level and not go deaf? Or take Aerosmith at full volume? No.

Trifonov playing "The Carnegie Recital" sounds very realistic at that level. Turn it down and it is just like moving further back in the hall. Same with Gould playing Contrapunctus 1-9 on Organ.  WOW!

As an aside, there was a Tip someone posted over in the Analog Forum for us old geezers about trimming our ear hair for better fidelity. And that reminded me that I need to cut my hair!

Happy Holidays!

Mike

mikewerner OP
119 posts
 

UPDATE:

After pushing the 4367s around for awhile with the powerful SS amps (AHB2's in MONO configuration) i decided to try some lower power tube amps.

First in was a pair of CAD-300SE. They are 300B SET with 11W output. I found that I must be much closer to the speakers and keep the volume way down. First impression was they do a lot of what the AHB2's do but quieter. Then I thought "I guess I don't care what those singers are saying - it sounds so beautiful." Then a mechanical transformer hum became annoying, especially since the volume is down and I had to sit so close. Also, the tube amps are much more finicky WRT line voltage. A Variac was pressed into service for regulation. These amps need 117V not the 121V which is more usual here.

Next I put in the ARC Ref 75SE. That was a bust. V3 flamed with a runaway bias. I called ARC service and they are so backlogged that can't take the unit for 5 months. I am on a waiting list for the repair. Go figure. At least it didn't fry a speaker.

Next was a single AHB2 and it just has a little less jump than the pair of AHB2's.

Next is 25W of glory in the form of a Luxman MQ-88uC.   I LOVE, LOVE, LOVE it! It too needs the voltage down to 115V. Push Pull KT-88 in triode. Beautiful and relaxing sound on the JBL4367 with NO Fatigue! And just enough power to turn it up a bit.

On the way is a Pass Labs XA-25. I can't wait to hear how it plays with the big speakers.

As for reference level, Volumes equivalent to realistic levels are just to tiring though possible with these speakers and the AHB2's

So there you have it. I hope this is entertaining to some readers. It certainly is to me.

yage
399 posts
 

@mikewerner 

Very interesting. i found that when I optimized my playback chain with low noise, low distortion gear (Benchmark DAC3 B + HPA4 + AHB2), I'm able to listen without fatigue at higher volume levels and for as long as I want.

 

I've owned gear in the past that output higher distortion and they always sounded good at certain volume levels or with certain genres but the Benchmark system lets me enjoy everything I want to listen to without problem.

 

In any case, if you're interested in how some studios may set their reference levels, here's an article from Sound On Sound - 'Establishing Project Studio Reference Levels'. Maybe you've already come across it yourself. Personally, I listen to music around 72 dB average SPL C weighted when measured with my RadioShack meter. The volume knob setting to achieve this varies with source material (e.g. -20 dB on most classical, -26 on most jazz, and -30 on contemporary pop music). I call it comfortably loud.

More to discover