# General questions



## JCD (Apr 20, 2006)

Brian,

I had a some general questions for you if you have the time:

1) How did you decide on the speaker drivers you use?
2) How often do you try out different speaker drivers?
3) Do you test the drivers before installing them in one of your speakers? If so, what kind of tests?
4) What importance do you put in the crossovers? I.e., how much do you spend for the caps, inductors, etc. Are you brand loyal? Etc.


I'm sure more q's will come up, but these were the ones at the top of my list.

JCD


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## Brian Bunge (Apr 21, 2006)

These are all great questions. I'll do my best to answer them.

1) Well, I mainly just see something that looks interesting either from a material standpoint or from a parameters standpoint. For instance, a few years ago I got really interested in trying out small, inexpensive full range drivers. Most of the ones that appealed to me ended up being 3" drivers from Tang Band and a few other manufacturers. I tried 6-7 different ones talked to other people who were doing the same before deciding which I liked best. This is how I ended up designing the Micros you see on my website. 

2) I try out different drivers whenever something interesting comes along and I happen to have the time and funds to play with them.

3) I haven't tested any drivers from the standpoint of taking acoustic measurements yet. I do use several different programs to come up with the enclosure design for a specific driver I want to use and then move on to the crossover design. In the past I've had others do crossover designs for me based on published measurements on drivers or from their own measurements of the drivers I wanted to use. I've recently put together a measurement setup and will begin taking measurements in order to do my own crossover design in the near future.

4) Well, I think these days everyone is aware of the importance of the crossover itself to the speaker design. I only use electrolytic caps when I need a large value and it's only used in the woofer section of a speaker, usually in a 3-way design. The majority of the time I use Dayton or Solen poly caps for my speakers. I've used Sonicaps in a few speakers and can tell a difference when used in the tweeter section. It's not a night and day kind of thing, but it is something that can be heard in a side by side comparison. I've recently purchased Jantzen film caps for the first time for use in my new center channel speaker.

For coils, I only use air core inductors. I've used the copper foil inductors a few times but really don't hear a difference and the added cost just isn't worth it, IMHO. Also, I've seen the copper corrode badly over time. For really inexpensive designs I've used air cores wound on a nylon bobbin, but for higher end stuff I use either Erse Perfect Lay inductors or the Jantzen line of inductors. 

I hope I've answered your questions. Please let me know if you have any others.


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## Sonnie (Apr 11, 2006)

I have some general questions myself...

1. Are you familiar with or ever used, or considered using "Soundcoat"... a ceramic compound which is in liquid state when applying and hardens when dry after a couple of days. Supposedly very effective in damping unwanted cabinet resonance, around 10dB in audio range above 200Hz. 

2. Are you familiar with or ever considered using Auricaps or TRT capacitors... and Erse coils?

3. Have you used or considered using L-pads for level adjustment of midrange panels and tweeter in your crossovers.

I don't know much about these things myself, but have heard good things for using them, although I'm not sure how cost efficient they would be and if the improvement would be worthy of the extra costs.


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## Brian Bunge (Apr 21, 2006)

Sonnie,

1) I'd never really heard of Soundcoat before. I did a quick google search and it does sound interesting. I'm not totally sure how beneficial it would be in a well-braced cabinet, which is all I build! I usually line the walls with acoustic foam and/or stuff the cabinets with polyfill to help absorb the back wave of the drivers. My big 3-ways have both of these in them along with extensive bracing.

2) I've heard of the Auricaps and TRT caps, but never used any of them. I'd be more than happy to use them if customers are willing to pay the premium.  I've used some Erse coils before. My only real concern with coils is that they have the DCR required by the crossover design. Sometimes that means you have to have large, 14 gauge air core inductors. You should see the monsters in my towers.

3) I've never really thought of using L-pads. I'm sure it's a nice feature for customers who want to tweak their speakers to their rooms. Again, if a customer wants that, it can be done, although 4 ohm L-pads are pretty much non-existent these days. So they really only work for 8 ohm loads. Although, they do have some dual 8 ohm "stereo" L-pads that could possibly work if wired in parallel.


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