Educational speaker driver choices?

[Few]

I'll be teaching a short course on speaker design and construction at a small liberal arts college in a couple of months. I'm seeking suggestions for speaker drivers I can purchase for demonstration and/or prototyping purposes. I'll be using SoundEasy v11, a Berhinger mic, an Agilent arbitrary waveform generator, custom LabVIEW software, and digital oscilloscopes for testing purposes. I'll also have a Berhinger DCX2496 Ultradrive Pro Digital Crossover (if it ever shows up) and a Berhinger DEQ2496 Ultracurve Pro Digital EQ/RTA. I'd like to choose a few drivers that are particularly useful for one or more of the following purposes:

1) Demonstrating desirable or undesirable driver behavior

2) Demonstrating different bass alignments and their time and frequency domain behaviors

3) Teaching the science behind the speaker's performance or even the math behind a measurement technique (eg, FFT)

I thought I might choose, for example, aluminum-cone and polypropylene-cone 6.5 inch drivers to demontrate the differences in their behavior, especially at higher frequencies. I'll probably have one of the students build a prototype electrostatic mid/tweeter as well, since I have some experience with the ESL's. I'm going to steer clear of purchasing very high end (expensive) drivers for demo purposes, but I want to have one or two examples of well engineered drivers (maybe a couple of smallish woofers and a couple of tweeters) to show what good performance looks like.

In the past I've helped each student build complete speakers starting from sheets of MDF, but I spent too much time making sawdust and not enough teaching the science. This time I'm hoping to purchase some premade cabinets with blank front panels so that we can try putting different drivers into the same premade cabinets and compare.

If you've run across any drivers that you think might be particularly useful for these purposes, please share the information. I can later share information about what my students learn about each driver.

Thanks in advance,
Few

[cotdt]

You can demonstrate cone breakup using the Dayton RS180 drivers.

[mtnickel]

The Dayton DA175 is a cheap mans Seas L18. Very good bang for buck. This is just going off Zaphaudio.com (john Krutke). Aluminum cone, so you could show the break up modes and the need for steep roll off or a low crossover frequency. Bass performance on it is good but gets a little out of line the harder you push it. The Dayton classic line are great value too for paper cone. I think in terms of bang for buck, dayton can't be beat for mids/woofers.

A few good performing drivers would be Seas 27TDFC or 27TBFC/G. Many use it and it can't be beat for anything under $100.
As for midwoofers, the RS series are great low distortion drivers.

Good luck with the class. SOunds like a lot of fun.

Mark

[soongsc]

The Jordan JX125 aluminum cone is a good driver to look into. My tests have shown some indication that seems to be interaction between the cap and the cone which should be an interesting project.

[Few]

Thanks very much for the help, guys. I'll take a look.

My copy of SoundEasy v11 and a soundcard just arrived today, so things are gearing up. Any other good driver or project ideas?

Few

[DDF]

http://www.partsexpress.com/pe/pshow...number=264-817

$20, has al break up, can be used full range or crossed over, and works in vented or sealed.

For the price, it sounds very good too.

[Karsten Sømand]

Hi Few!

I think it could be a good idea looking at some 4 " Vifa speakers.

The first one, MG10MD09-08, is unfortunately not produced anymore, but try Madisound - they might have a few left if you are lucky. This driver has a glass fiber cone, very smooth FR. Please remark that it goes up yo approx. 15-16 kHz almost ruler straight. Furthermore, please also remark the very smooth and controlled roll-of 30 + 60 deg. off axis. The impedance curve is without any "peaks" and "dips" which means that this driver behaves almost ideally. I have, unfortunately, not seen any distortion measurements. The acc-factor (Bl / moving mass) is more than 1000! If you don´t like the sound of a glass fiber cone it is possible to give it a thin layer of coating (quite normal for DIY people in Denmark)

The other one, PL11MH09-08 (Peerless V-Line) is almost as the one mentioned above, but with a coated paper cone. The frequency response is also very fine, and it has a little higher sensivity.

I hope you can use my suggestions. Looking forward to reading about your project with the students.

Kind regards

Karsten (Sømand = Sailor i Danish )

[soongsc]

Originally posted by Few
Thanks very much for the help, guys. I'll take a look.

My copy of SoundEasy v11 and a soundcard just arrived today, so things are gearing up. Any other good driver or project ideas?

Few

I have a thread recording my experiences with SoundEasy. Since the software is designed with more of an academic flavor/approach, people used to using commercial software from large companies might find is confusing to get used to.