Need Advice or Options on Inductor coils

[speedemon]

Hello All

I’m new here found this site tonight by surfing the net trying to learn more on inductor coils. I have a friend that’s trying to help me tune my speakers in my home I have built a couple of years ago. Just to give you an idea of what I have which we’re trying to tune is a set of custom built Dynaudio speakers 66” weighing close to 500lbs. It has the D’Appolito designed configuration with the two 30W100 woofers, two 17W75LQ mids and the Esotar tweeter set up for bi-wiring, being driven with a Krell KSA300S through a Klyne System 7 preamp which I’m hoping to replace soon with a Krell preamp. Ever since moving into my dedicated room which measures 28’X 16’ I have lost some bass from these speakers. What I’m looking for is more gain on the lower end. I have talked to the speaker designer that built this pair which was tuned for my previous home whrer the room was much smaller. He said what he was going to do was to take out my Solen 4mh air core inductor coil and replace it a steel laminate inductor coil with less resistant. I have been out of it for a while and I’m just getting back into the hobby. What brand of coils now these days are the best of the best on the market at a no cost factor that would be low resistant that you may know of that you can recommend. Also has anyone heard of Goertz brand of air core foil inductors? I’m open to suggestions and my main issue is trying to get the lower end back. Any info would be appreciated.

Thanks

[Wombat]

One thing that makes me wonder. If you lower the resistance of the coil in front of your bass it will result in a lower frequency adjustment and the presure level will sink not boost.

[jackinnj]

Martin King (MJK on this forum, probably frostbit in upstate NY and unable to move his fingers about the keyboard) has done a lot of work with MathCAD allowing you to play around with values and derive an optimal box situation. Just using the stock values for one of his sytems we can illustrate the effect of inserting series resistance into the system -- the first chart has zero inserted resistance, the second has 2 ohms :

[speedemon]

If not going to a lower resistant coil will do the job, t what would you guys recommend to bring the bass levels up with more sound pressure, since this room is twice the length of my old room.

[Cal Weldon]

If it's set up for bi-amping, why not do that? I know it's expensive but the results may surprise you.

I wouldn't renew an air core with an iron core unless it was parallel (bypass). As mentioned, if you reduce the impedance, you are changing the XO frequency. Not a good thing.

EDIT: I reread your post and it says bi-wiring not bi-amping. Sorry for the confusion.

[Salas]

Originally posted by speedemon
Hello All

I’m new here found this site tonight by surfing the net trying to learn more on inductor coils. I have a friend that’s trying to help me tune my speakers in my home I have built a couple of years ago. Just to give you an idea of what I have which we’re trying to tune is a set of custom built Dynaudio speakers 66” weighing close to 500lbs. It has the D’Appolito designed configuration with the two 30W100 woofers, two 17W75LQ mids and the Esotar tweeter set up for bi-wiring, being driven with a Krell KSA300S through a Klyne System 7 preamp which I’m hoping to replace soon with a Krell preamp. Ever since moving into my dedicated room which measures 28’X 16’ I have lost some bass from these speakers. What I’m looking for is more gain on the lower end. I have talked to the speaker designer that built this pair which was tuned for my previous home whrer the room was much smaller. He said what he was going to do was to take out my Solen 4mh air core inductor coil and replace it a steel laminate inductor coil with less resistant. I have been out of it for a while and I’m just getting back into the hobby. What brand of coils now these days are the best of the best on the market at a no cost factor that would be low resistant that you may know of that you can recommend. Also has anyone heard of Goertz brand of air core foil inductors? I’m open to suggestions and my main issue is trying to get the lower end back. Any info would be appreciated.

Thanks

Measure it first with an RTA if you can so we can really help you.

[infinia]

Originally posted by Cal Weldon
If it's set up for bi-amping, why not do that? I know it's expensive but the results may surprise you.

I wouldn't renew an air core with an iron core unless it was parallel (bypass). As mentioned, if you reduce the impedance, you are changing the XO frequency. Not a good thing.

EDIT: I reread your post and it says bi-wiring not bi-amping. Sorry for the confusion.

First thoughts may be best after all.
Bi amp you can dial in the crossover points and levels to your taste.
Room placement may be best/most overall economical solution.

Lowering bass drivers source resistance may reduce cuttoff frequency and damping in a negative way for maybe 1-2 db crossover loss improvement at best.