Asl
#51
01-09-2008, 11:10 AM
Re: Report back on possible ASL malfunction
Thanks for this info. Did you ask if we can change the threshold from 100 mph to 45 mph? There must be some (hidden) setup menu that we are not aware of.
Well, after numerous e-mails back and forth to one of the JBL engineers at Harman-Becker Automotive in Martinsville, IN, I can report back as to what the Camry's audio system actually does:
So, there you have it!
Stan
- The ASL is not malfunctioning, but is behaving as designed.
- The ASL applies a mild speed-dependent overall volume boost, amounting to only +3.7 dB at 100 miles per hour.
- The ASL also applies a mild speed-dependent boost of the low bass (around 40 Hz), amounting to +3.5 dB at 100 miles per hour.
- The audio system applies substantial "loudness control-type" bass and treble boost as the volume control's setting is reduced from full volume. This amounts to +15 dB at ~40 Hz and +8 dB at ~10 kHz at the lowest volume settings (and much less, but still very significant, boosts at more normal volume settings).
So, there you have it!
Stan
#52
01-09-2008, 12:36 PM
Re: Asl
supertester — I was not told about the existence of any user-changeable parameters inside the JBL amplifier. As I understand it, it's all hard-coded in the internal firmware. Sorry!
Stan
Stan
#53
01-09-2008, 02:49 PM
Re: Report back on possible ASL malfunction
I... don't think I interpreted that chunk of information to mean it kicks in at 100 mph, just that the curve of increased volume relative to speed crosses the +3.5/+3.7 dB line at 100 mph. Lower increase at lower speeds. It's just an indication that the adjustment isn't substantial if it only changes that much over 100 mph.
But that's my interpretation.
But that's my interpretation.
#54
01-10-2008, 08:37 AM
Re: Asl
chestr's interpretation is correct. I'm not at liberty to release the ASL curve to you, but I can tell you that, as a function of speed, it goes through the following points:
Stan
- 0.0 dB gain boost at 0 mph
- 1.2 dB gain boost at 25 mph
- 1.9 dB gain boost at 50 mph
- 3.0 dB gain boost at 75 mph
- 3.7 dB gain boost at 100 mph
Stan
#55
01-16-2008, 06:07 PM
Re: Report back on possible ASL malfunction
The ASL is not malfunctioning, but is behaving as designed. ... The ASL applies a mild speed-dependent overall volume boost, amounting to only +3.7 dB at 100 miles per hour.
The ASL is intended to adjust the stereo volume to compensate for the increase in noise level due to vehicle speed. However, the actual increase in ambient noise is clearly greater than the amount they are compensating for in this vehicle.
Perhaps they should measure the amount by which real drivers actually turn up the volume while driving at speed, and correlate that volume setting with vehicle speed. Then design the next generation of ASL to do the same thing. It might even be necessary to do some experiments in the same model of vehicle for which they are designing the stereo.
The amount of ASL compensation should also be adjustable. Some drivers like more than others. And the roads in some counties are rougher and make more noise than the roads in other counties. Give us a range adjustment, instead of or in addition to the on/off switch. Or, use a sensor to measure the actual ambient noise dynamically.
#56
01-17-2008, 07:14 AM
Re: Report back on possible ASL malfunction
The amount of ASL compensation should also be adjustable. Some drivers like more than others. And the roads in some counties are rougher and make more noise than the roads in other counties. Give us a range adjustment, instead of or in addition to the on/off switch. Or, use a sensor to measure the actual ambient noise dynamically.
#57
01-17-2008, 09:58 AM
Re: Asl
SteveHansen — Your suggestions are good, and I had already made similar suggestions quite strongly to my JBL contact. The problem is that just raising the overall volume as a function of speed (as the ASL does) is a suboptimal strategy. First, the 3.7 dB of gain boost at high speeds is too little. Second, if one boosts the volume by the amount required in order that the quiet musical passages remain audible above the background noise at high speed, the loud passages become unbearably loud. I actually went on to suggest that what is needed is a compressor that raises the level of the quiet passages while leaving the loud passages unchanged. The amount of compression should be user-adjustable. Philips incorporated just such a compressor into their very first car CD player in 1982 or 1983! Why isn't one offered now, 25 years later? That's what I think JBL should persuade Toyota to let them do!
Stan
Stan
