Dumb question time.. is a cleanbox always needed? Or just if you want high volume range coming from the source (Sonos, Musicast amp, etc)

No.
They are so not always needed that I've worked on hundreds of systems that do not require a cleanbox. In fact, I don't remember ever even hearing of the cleanbox before! (Turns out it's been mentioned a couple dozen times here over the years, in about a half dozen threads.)

All pro equipment is designed to work together without the need for a device like the Cleanbox. There's also enough gain in all the equipment I've ever seen to accommodate the lower consumer product signal level.

An earlier thread mentioned gain settings in a Crown amp that are set in software; they were low, resulting in the controls on the amp not being able to go high enough. If you really want to know what's going on, you'll need to measure your input and output voltages, not just turn the volume up all the way.

3:45... what? Someone waited that long to call them? No lo comprendo.

At 3:45 one morning, the cops were at the door of my client. I know this because the still image (on my phone, all I could see were stills showing who had rung the doorbell...Doorbird) was dated with the time of day as 3:45 AM.

In my area noisy neighbors are not a priority. This could have been response to a midnight call.

Respectfully disagree, says the man who deals with signal level differences on a weekly basis. Not all pro equipment will deliver satisfactory spl when run with a consumer device.

Fred,
The question was "Is a cleanbox always needed?"
I said no. (Perhaps one should be in one's toolbox despite my never having had a need for it.)

I went on to describe my experience. You can't very well disagree with one's experience, since that's saying "it didn't happen."

I don't disagree with you, since you have found that consumer products mixed with pro products don't ALWAYS give the full volume.

I will say this. Every consumer level output product that we have paired with a Pro amp has sounded better with a CleanBox installed.

So yes a CleanBox is always needed.... :)

For years it's been known -- so long that, unfortunately, it's now lore with very little
in the way of written up explanation -- that in blind testing, two sets of speakers that are identical except for one being not even one dB louder than the other, the louder speaker will be judged to sound better.

One fact that generally supports this is that, within a range several dBs wide, the ears have a flatter response curve with louder sounds.

I agree with Fred about levels. If the pro equipment is expecting 0dBm into 600 Ohms, not all consumer equipment will appreciate this. Some of the older consumer equipment will barely reach 0.5V into a few thousand Ohms.

And I agree with Ernie too. Cooking up a valid A-B comparison is surprisingly difficult because fractional dB differences in level will tilt the comparison.

Early in my audio career I worked for a (now defunct) retail chain. On the first day of salesman training one was introduced to the level match system for A-B testing and shown how critical the level match was. On day two we were introduced to the idea that this could be used to sell the "right" speaker (the high margin speaker in stock). Commissions and bonuses were more likely for sales people who sold what was in stock.

Fletcher Munson curve is what Ernie is talking about.

Fred, that's true:



The louder sounds result in flatter response of the ears.

You'd think if the ear's response falls off at some particular sound level as we move away from the reference frequency (1kHz), that the curves would fall off to the left and right. These curves look upside down because the curve away from the reference point shows the level of sound it takes for the ears to perceive that other frequency to be as loud as the 1k reference.


What I just now realized, after all these years in the industry, is just why speakers a bit louder than other speakers sound better. I had always thought it was simply that the sound seemed closer, or the image better, or something. Only now did I realize that like many things we put together, the speakers and the ears ARE A SYSTEM and parts of a system interact with one another.

It's not just that one set of speakers is louder, it's that the transfer of the music from wire to nerve impulse in the head is better with a slightly louder speaker because the EAR part of the system performs better! The SPEAKER doesn't sound better, the EAR works better and makes the speaker seem better. To all those who have recognized this particular aspect for years, I'll say it for you: Well, duh!

efficiency of speaker matters

It always does.

I think you're commenting about how this "sounds better due to volume" thing works, but the issue I've been talking about refers to two identical speakers and the fact that if one is slightly louder than the other, the louder one will be perceived as sounding better. Since the speakers are the same model, the efficiency of the two will be the same.

In that wonderful (not) retail setting I described above, we could place the same physical speaker on both 'A' and 'B', but skew the level a bit. The louder version always sounded "better".

Another interesting observation about that A-B comparison was that the listener had to hold the button down for 'B'. This introduced a slight bias against 'B' because 'B' required more work. One quickly learned to place the speaker that one "should" sell on 'A' -- regardless of any level skews.

The sales person could also stand in the sweet spot for 'B', forcing the listener to stand in the sweet spot for 'A' -- the correct speaker to sell.

As I said, setting up a valid, unbiased A-B comparison protocol is not easy.