Inductors

saabracer23

Member
2006-05-12 11:17 pm
Hello all, I am wanting to rebuild/design some crossovers that I have in a pair of commercial speakers. What is the general rule about inductors. How far off in each direction can I go with the DCR without effecting the sound noticeably? I heard it's ok to go lower by any amount but you don't want to go higher by much. I thought I would check before buying. Is it acceptable to go off the mH a little? Reason I ask is because I'm trying to save a bit where I can.

Thanks
Dan
 
Yeah, it depends if the inductors are in series or parallel. You also want to watch their saturation power unless you use air core which don't saturate (but have a higher DCR).

Standard advice #17: speakers last a LONG LONG time, spend the money and do it right. (But it's true, sometimes you can use a slightly different standard coil and save money and maybe reduce DCR).
 
Hi,

In rebuilding commercial speakers its simply not worth "upgrading" the
inductors unless they are very poor or underated in power handling.

In any good design the DCR of the inductors will be included in the balance,
reducing the DCR of the inductors should have no positive effect.
The main thing to do is replace any electrolytics with modern ones, and
possibly replace any electrolytics in critical positions with film types.

rgds, sreten.
 
Last edited:

saabracer23

Member
2006-05-12 11:17 pm
http://www.polkaudio.com/forums/attachment.php?attachmentid=18794&d=1155785202

Here is a link to what I'm going for. I have the original ls90 which the general said has undefined bass that is muddied and "wooly" midrange. So Polk changed it to this crossover and everyone was happy. The original, mine, have a 4.0 mH inductor in place of the 1.0 mH, the cap was changed from an electrolytic to Mylar but I'm going poly, and the resistor went from a 1.5 ohm I believe to the 1 ohm. Layout is identical. All are iron core with the exception of the .4 mH

Dan
 
[IMGDEAD]http://www.polkaudio.com/images/home/medium/black/ls90.jpg[/IMGDEAD]

Hmmm.......

Very simple crossover, and changing 4.0mH to 1.0mH changes it from
a 2.5 way to IMO a very poor 2 way, I've no idea what is going on.

rgds, sreten.

undefinition
Zaph|Audio
FRD Consortium tools guide
RJB Audio Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
Humble Homemade Hifi
Click below to go to
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
 
Well I'm completely open to redisigning the whole crossover and doing point
to point. Any ideas Sreten? That is actually what I would prefer to do. If
needed I can ship out a woofer and tweeter so someone can get ts params.

Dan

Hi,

All the info as to how do that is contained in the links I posted.
TS parameters are only for the bass, you ideally need FR curves.
In box is a lot better and easier than large baffle measurements.

rgds, sreten.
 
Last edited:
Well I'm completely open to redisigning the whole crossover and doing point to point. Any ideas Sreten? That is actually what I would prefer to do. If needed I can ship out a woofer and tweeter so someone can get ts params.

Dan
Dan,
Have some patience and take your time.
From my point of view (if the speaker/drivers are the same), and you want to do the improvements/changes said, you will need a new xover. New R1, C1 and new L3.

L1 and L2 are the same, but, you can buy new ones to have a brand new plug-in xover and be able to compare.
You may have to get used to the idea that, you might have to change some of the components from final design, for your likings/room/amp etc.
Now let's check all the components one by one (air core/DCR, etc.) wherever you want to start.:cool:

If you want to just buy the new components R1, C1 and L3 you will have probably less work. Start with the tweeter and compare before changing the woofer coil. Then solder the new coils and check for final testings. You have L value and DCR listed. The HF change will pad it a little. The LF change will make it more lively. You can also change DCR for L2 to balance the Mids. More DCR = more attenuation on "lower frequencies".

Mr. Polk will be proud of you (in his secret island).:D
 
Last edited:

saabracer23

Member
2006-05-12 11:17 pm
No I'm wondering if I should even put money in them. I could part them out and sell the drivers and build a pair of smaller towers. Since almost all of the drivers are on sale I was thinking the mini statements. I'm sure those would be in a different class than the polks. What do you guys think of this? Any other towers in the same price to consider? (no bookshelves as a pair killed my last cat). Or should I just try to improve the polks? They'll be paired with a AE15-h sealed.

Dan