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Bass distortion before tweeter distortion with a monitor at high volume?

I am looking at getting a set of monitors for a second system in a small room (12' x 10') , but I would also like the flexibility to play them in my main system in a room that is larger (13' x 25') with cathedral ceilings.

Let's assume that the small speaker I end up with won't be able to produce enough volume without distorting in the larger room.  Most of what I have read indicates that a subwoofer would solve the problem.  My understanding is that I would want to high-pass the bass on the speaker before it reaches the point of distortion, solving that issue.

If that is true, that leads me to believe that generally the tweeter would not be distorting unless the volume is at a higher level.  Is this normally the case?  If not, it seems there would be no point to using the sub. 

To restate the question:  With a high quality monitor, is it safe to say that the tweeter can play at higher volume without distorting compared to the woofer?  I am speaking in general terms here - I am sure there are exceptions.  Thanks.
abnerjack

Showing 3 responses by sboje

sboje
38 posts
 
Assuming that you aren't amp limited...

I believe you would increase the headroom of the system significantly with a high-pass. This calculator (below) indicates that the necessary excursion of a driver producing 40hz is 4X greater than the same driver at 80hz. This would probably clean up your bass and midrange also.

If your speaker manufacturer uses the same tweeter in a larger 3 or even 4-way design, I would expect it to breeze along just fine.
http://www.baudline.com/erik/bass/xmaxer.html



sboje
38 posts
 
I don't agree with you, elevick. 

Distortion goes up significantly beyond 90db for almost all speakers. One of the online magazines does a signal-noise sweep using both 90db and 95db volumes. So with small speakers you're approaching the cliff with only 2 watts of power (assuming 87W sensitivity). 32W and your speaker distortion will be pretty bad.
sboje
38 posts
 
Here is the site I was referring to. In their distortion tests, they show the distortion as DB, not percentage. There are calculators if you want the actual numbers. In short, the number of db between the signal (top line) and distortion (bottom line) is what you are looking at.

http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=941:nrc-measur...


The takeaway from the KEF LS50 graph is that little mid-woofers are really pretty terrible at bass. I think it also dispels the myth that most subs aren't "fast enough" to integrate. Most subs have many many times lower distortion at bass frequencies. 

If you go to the Measurements menu and select speakers, there are quite a few speakers to choose from. For larger speakers, they do a test at both 90db and 95db. 

It doesn't look like most tweeters have significant measurable distortion at 95db.

I can also tell you that if I plug the ports of my Revel M106s, the midrange clears up a good bit, so even limiting the woofer's excursion physically helps. Unfortunately, that makes integrating with a sub difficult because the sub has to play at a little higher frequency and I get localization of the sub's sound.

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