Midrange Analysis

Midrange Analysis

Ideally, I would like to pick a driver based on these 6 characteristics

1. Personal Audition
2. Non Linear Distortion tests
3. Reputation
4. Frequency Response
5. Waterfall
6. T/S Parameters

The Problem is:

It is very hard to audition tweeters free of other influences- you pretty much have to buy the driver in question. Non Linear Distortion and Waterfall are rarely published. Reputation is subject to the bias, opinion, and group think of others. (I still rely on reputation)

Assuming we can’t audition or we want to limit our audition, we are left with T/S parameters (which are often wrong), frequency response, and reputation.

The question is: based on T/S parameters and frequency response what would you look for in a mid?

Some things I would look for:

1. Smooth frequency response in the passband+an octave above and below
2. No serious resonance within two octaves above the cutoff frequency(depends on XO slope)
3. A high Re/Le ratio
4. A high BL/Mms ratio

What other criteria would you use to evaluate a potential mid and how would you rank their importance?

I would also say both male and female vocals are the most important reproduction targets, and comments should reflect this.

I would limit the discussion to the mid in a closed box.

I am leaving crossover points open right now, because I would like more of a general theory and philosophy discussion.

Thanks a lot,



2005-03-26 2:31 pm
The first thing to look for is the type of cone/dome/ribbon material. The material has different audible signatures. Decide on the type you feel best for your taste.

Then look at the impedance curves. If the impedance within the frequency range you what to use for each driver does not exceed twice the lowest value in that range, then it can be a candidate.

Next pick the impedance curves that are basically smooth, and do not have rapid phase changes other than the normal natural frequency.

Then go by reputation and price and match among the drivers.

Hope this gives a good start.


2001-02-19 10:38 pm
you pretty much have to buy the driver in question.

The simple path cost more but yields the best results.

1. Make a list
2. Buy one of each
3. Listen to the speakers using an active crossover & amp.

All your questions answered in no time. Worry about what is
audible vs. worrying about what is measured.
Thanks for your responses.

Soongsc: Yes a smooth Impedence curve is important, but most speaker mfg's use data smoothing techniques to give you a nice smooth curve, you will not see abrupt changes in published curves. I agree a high Re/Le ratio (flat impedence) is important.

thylantyr: Yes, unfortunately, I agree with you there is no real subsitute to buying and listening. I am just trying to see if there are any other methodologies out there. For instance, do you look at stiff or supple suspensions, different materials, phase plugs, very low xmax etc.


2005-03-26 2:31 pm
I think the impedance curves normally don't need smoothing, but it's just for initial selection. Once you've decided to try some drivers out, it is best to test them. Impedance curves will also show many other things if you know how to look at them.

Sensitivity would be the next thing to technically look at once you like the sound of certain driver candidate.