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True high-end Speakers need a midrange

To be clear, I don’t mean expensive, I mean high performing.

I recently built a new center speaker for my home theater and as I was comparing/contrasting design alternatives between a variety of designs, everything from expensive DIY designs to Wilson, Legacy, ATC and Focal and others the thing that stood out the most was this:

  • You can’t get high output AND low distortion without a midrange driver.

I say this as a person who has had pretty good success with 2-way speakers and really admire 2-ways from Fritz and others, but when push came to shove, there was no way to make a 2-way with very high output AND low distortion AND excellent off-axis performance without a midrange driver.

You can push many tweeters down to 2kHz or even a tad below but it is very hard to find a tweeter that will do so with low distortion at high volume. On the other hand there are many 1" domes which will perform excellently when crossed over at 3 kHz or higher even when driven hard, things you don’t see from a frequency response plot, or really any measurements from Stereophile which never plots dynamic range charts. It’s not just about the frequency response and imaging, sometimes it is about doing all of that under pressure that matters.

Similar, complementary issues are true for the woofer in a 2-way design.  First, good mid-woofers with good frequency responses through 2-4kHz are expensive, but as you push the crossover up 7" drivers and larger have to beam, right in the middle of the midrange.  Instead of a wide open sound stage you can hear anywhere they restrict where you can sit.

In a large, full range speaker you can push your design for high output even further by going with a 5" midrange for instance.  Not quite as wide as the 4" counterparts but lots of power handling and plenty of overlap with the tweeter and woofers. 

erik_squires

Showing 2 responses by ricevs

ricevs
1,474 posts
 

It is true you cannot get low distortion at low frequencies with a normal tweeter.....unless you waveguide it, cross it over very steeply or use multiples like Tekton does. However, if you use a planar midrange/tweeter and you cross it over at 400hz using a steep crossover using a dsp crossover, then you get incredible low distortion sound with a two way. The 10 inch Radian driver is one such driver that can do this. A single one will play at least 105db......use multiples of them in a line array and you can hit 120+db. A two way, mounted on an open baffle using 2 12 inch Beyma woofs and a single Radian is easy to build. What you do not get with using one 10 inch long planar is vertical dispersion. You would have to sit directly in front of the driver to get the flat frequency response to 20K.....stand up and the upper highs will go away. If you use 4 of them in a line array then when you stand up you will still have one in front of you. Here is link to someone who is going to sell a bi-amped speaker using 6 radians and also 6 12 inch servo woofers.......pretty big two way....he he. However, even 2 non servo 12s and one Radian on a single baffle would blow your mind. You could also make a very tall single baffle and have the two 12s at the bottom and 4 Radians right above them.

https://www.audiocircle.com/index.php?topic=177132.0

Here is some info and pics of the same guy who used one Radian and 3 servo woofs per side at the Lone Star Audio show.

https://www.audiocircle.com/index.php?topic=185895.0

 

ricevs
1,474 posts
 

My "build your own open baffle two way speaker" page now has more info and a few pics. All the designs suggested use 2 (or more) of the 12 inch Beyma drivers that Clayton uses. These speakers are very easy to make and will give incredible sound for very little money. I make little or no money sharing this information. I just think it is too good not to share. I have added some passive xover versions (can be driven by one amp), as well.

DIY Bi-amped super speaker (tweakaudio.com)

 

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