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
kota1
2,706 posts
 

I'm glad you started this thread, sometimes the importance of ear drum preservation gets "lost in the mix". The problem is some music starts softly, peaks loudly, etc. But it is something that needs attention once I moved from a condo with neighbors to a private dwelling, no limits if you know what I mean.

mikewerner OP
119 posts
 

Update:

In house now is a ML No. 534. OMG!!!

This amp and speaker combo effortlessly produces the whole thing.

Like a tapestry.

Noticeable are the dynamics. Quiet and LOUD! 

The JBL 4367 and ML No. 534 play exceptionally well together.

mikewerner OP
119 posts
 

UPDATE:

Having not had any parties on my porch for some time, I have switched back to the XA-25 in front of the JBL 4367. I'm glad I did. The 94dB JBLs get as loud as I want with the XA-25 and sound absolutely fantastic. The higher powered amps, ML534 and Benchmark AHB2, seem to prefer higher volumes and this is tiring. On the JBL 4367 the XA-25 gives me fatigue free listening and sounds more like music at all volumes.

Noticeable are the mid-bass textures and overall glare-free presentation. Those 15" woofers are handled with aplomb by the XA-25. It is amazing that 25W will do it, but these are a very special 25W. To paraphrase Dick Olsher, if the first watt is no good who wants the rest?

 

mikewerner OP
119 posts
 

UPDATE:

 

It is time for a correction. After playing around for a while with the low power amps I have come to the conclusion that they do not sound "more like music at all volumes." Instead each puts its own spin on the sound and gets to sound less like music at higher volumes.

 

Switching back to the Harmon duo, specifically the ML 534 paired with the JBL4367, noticeable are the MACRO dynamics and KICK. Back is the house filling sound!

 

So, if you don't feel too silly sitting near-field to these speakers the lower powered amps are fun... Unfortunately though, the first glorious watt (or 40 watts) may ultimately not be enough for the 4367.

mikewerner OP
119 posts
 

I forgot to mention,

Also noticeable with the change is the HUGE soundstage. With the right recordings I am immersed in a sound field that extendsr beyond the boundaries of the room. Be it Alan Lomax "Southern Journey" or Barbie "The Album" the effect is of being surrounded by sound.

More to discover