Pop Sound in my speakers when driven loud from studio recorded CD sources.


Hales Revelation 1 bookshelf speakers are what we're talking about.  Purchased in the mid 90's and had been in storage for about 15 years in climate controlled conditions.  Just started using them again.  I'm finding under most conditions they perform admirably all around.  When listening to certain studio recordings on CD where the sound is very dense or the recording has a compressed quality,  I am hearing a distinct "pop" (not part of the musical presentation) when, for instance, the drummer makes a strong slap on the snare drum or tom tom.  Low frequency bass response is still very agile and stable for these small speakers.  Is it possible my mid bass driver is stuttering under these circumstances?  These Hales are known to be power hungry speakers.  My amplifier is 85W per channel and I'm noticing this pop when I get the volume knob to about '12 o'clock' .  That's when it starts to sound loud in my listening room.  Other lesser sources like radio or streaming sources, don't seem to bring this on.  It's the up front, dense sound from a CD that does it.  

Any diagnostician out there that can tell what the disfunction is? ... what I can do about it, if anything?  Thanks!

chametzoo
Al... thank you again. I think that we are understanding the terms "compressed" and "spacious" in the same way in terms of dynamic range. It’s just that I handle the volume issue with each, differently than most, I guess. The truth is, I enjoy the wide dynamic range sound much more so than the narrow range employed in many of today’s recordings. Wide feels more live and ’in the room’ where as narrow sounds canned or unrealistic to my ears... hence my impulse to crank it up and make it feel more real. Perhaps a fool's errand ;-)

You’ve also added thermal overload, either in the amp or the speakers as a possibility. Is it possible that my Hales speakers, which I purchased new nearly 20 years ago and have spent the overwhelming majority of that time in storage and unused until very recently, may have some material degradation of say the membrane materials?



Hi All... I’m dredging up this 1+ year old thread because I think I discovered the solution to the problem I brought up here (I’m the orginal poster).

I had complained of a pop or burp sound when I was playing CD’s and there was a brief spike in sound, like when the drummer slaps the snare drum. This would happen at fairly loud volume. So, it was preventing me from turning the volume up on my amp to a nice loud concert level. If you want to know more, see the original post at the top.
All of my digital sources are routed through a Cambridge Audio DAC Magic Plus. This DAC has a "pre amp mode" with a volume control knob that is activated when headphones are plugged into the DAC... or when it is purposely selected by the user for speaker listening. Until now, I have been using the DAC without that pre amp mode selected... and THAT is when I find that the amp’s volume knob tops out early and the popping/burping sound starts happening coincident with the brief spikes in sound.
Now, I am using the DAC in pre amp mode and putting the amp’s volume knob much higher and then adjusting the DAC volume knob to get the music to a good listenable loud concert level... and to my surprise, I no longer get those pops/burps in the same instances that I was before. I believe that one of the posts earlier in this thread hints at trying that very thing out. But it was not until now that I tried it.  I'm still working on the optimal ratio between the two volume knobs.

Of course, I’m happy about this, but what I would like to know from you all, is what might be happening within my system between the receiver (pre amp/amp) and DAC (with pre amp volume control activated). Now there’s actually 2 pre amps working simultaneously. I don’t really have the technical knowledge to know why it’s working better, but I’m sure curious. Thanks!
Glad that the problem is finally solved.

It seems that what I had said in a post which I subsequently deleted (because it seemed inconsistent with the sensitivity of the problem to the setting of the volume control), but which I quoted in a subsequent post after you asked what I had said, was in fact applicable:

Given the 180 mv sensitivity of the Marantz receiver and the 2.1 volt maximum output level of the DacMagic+ unbalanced outputs, it seems very conceivable to me that the problem may be due to overdriving whatever circuitry in the Marantz precedes (i.e., is "upstream" of) its volume control.

As an experiment, and conceivably as a permanent solution, try enabling the DacMagic’s digital preamp function, reduce its volume control setting significantly, and increase the volume control setting of the Marantz to provide preferred volume levels. See if the problem still occurs.

I can’t explain, though, why putting a smaller signal level into the Marantz has helped, given that the problem had only occurred at higher settings of the volume control. Detailed knowledge of the Marantz' circuit design might be required to explain that.  As I indicated earlier sensitivity of the problem to volume control settings would seem to signify that the "pop" is being introduced "after" the volume control in the Marantz’ internal signal path, where signal levels are presumably about the same for a given perceived volume regardless of whether you are using the DAC’s preamp function or not.

Regards,
-- Al


Wow... Thank you again Al.  I'll continue to monitor the situation and try various other CD's where I know the "pop" was happening before.
As you point out, the mystery may be within the Marantz's circuit design:
Detailed knowledge of the Marantz' circuit design might be required to explain that
At this URL, scroll down to the bottom, and there are links to PDF's for "schematic" and "diagram" for the Marantz 2270 I'm using:http://spacebullet.net/marantz-2270.html.  If you feel like it, take a look; my curiosity continues!  Best, Mike