bsc filter

[Jamesuk1]

Hi,I have a lovely pair of Chilli Changs.They are fitted with Fostex FE 168e Sigma fullrange drivers.I have recently fitted Fostex FT17h Horn tweetrs to the rear, to act as Ambience tweeters .They are crossed over at around 10k with a second order slope so they come in quite gradualy.I also have fitted Fostex Adjustable L-Pads for these too.I have had these speakers for around 8 months now so they should be run in .Having listened to these for a long time with many different types of music i find just one small problem , mainly but not always, with my vinyl front end is that the upper midrange can sound just a touch too hard and glassy at times.I have read some of you use a BSC filter to tame some frequencys down a tad.What is a BSC filter and can i use one in series with my 168 fullrange.I am sure the problem lies in the upper midrange lower treble as i can turn down the rear tweeter and its still there. Any ideas please would be most welcome.In all other aspects these speakers sound so revealing and transparent.They are very critical of recordings at present though ! Thanks....James

[just a guy]

BSC = baffle step compensation

This may or may not be what you need depending on what frequencies are bothering you. BSC will lower the level of all frequencies above a certain point (IIRC - I've never used or studied one before). It's used to offset the finite size of the baffle.

If it's only the upper mids that are problematic (lower mids and high treble are ok), bsc may not be the best bet. In this case where the problem is only over a narrow band a notch filter may be a better bet.

OTOH, there may be other options as well. Eq will do everything a physical component filter will and more. Some form of room treatments may be effective on this front too. It really depends what is causing the issue. Could be that the tweeter is just coming in too low too.

[just a guy]

And don't forget that these double mouth horns are supposed to be several feet from any walls as per the designer's instructions.

[Jamesuk1]

Thanks for the replys,I am using them around a foot from the side walls as in my small 12ft wide room they sound best this way.I might look into either a notch filter or side wall treatment...

[just a guy]

I would try to identify the offending frequencies before spending money on blind tweaks. If you have an eq you can try to "fix" it and get an idea of what components you need to buy for whatever filter fits your needs. Better yet, some measurements might indicate where the problem is and how bad it is.

Maybe a driver tweak might be more effective than a notch and side wall treatment. It all depends what is causing the problem. Maybe the fullrange driver could use a lp filter to blend better - might need a front firing tweeter for that though. If that is the case it's best to address the problem at it's source.

[Jamesuk1]

Im not sure exactly what frequencies are causing the trouble.Its maily on some loud female voices and instruments such as trumpets and saxophones etc. What driver tweeks are there for the Fe168e Sigma....?