How to make all this work (SPL to REW to BFD) help

**brucek** · **08-08-06, 05:51 PM**

Quote:

but not sure what a broader filter is ,but I will figure it out

If that's the case you should take time now to read any sections of the BFD GUIDE and also your BFD user manual on bandwidth of filters.....

brucek

**rlammi** · **08-08-06, 06:59 PM**

I am brucek ,I will have it figured out and get a graph reran to check out once i get all the filter adjustments corrected ,and I finally figured out what you ment
about playing around wit the filters, I didn't have the corrected box checked so it wasn't showing me the changes the filters made will tweak it and let you know .Thanks again brucek .

**ThomasW** · **08-08-06, 09:13 PM**

Broader filter= wider bandwidth filters like 120/60 if you're using a BFD. Make 'shelving' filters to pull down the higher frequencies. I know Bruce is using a similar filter for his settings. I don't remember exactly where he discusses it's operation.

**rlammi** · **08-09-06, 09:22 AM**

Thomasw or brucek

what is a shelving filter ,I have heard it before .I finally understand the wider or broader filters ,I am going to reinput the data and then play with the filters a little more and then input them into the BFD and retake the measurement and then I guess it will be tweaking from there .I will repost once I get a chance to rerun reqw and see were any more adjustments are needed .Thanks all for the input and advice .I am ready to put a DONE stamp on this thing .

**ThomasW** · **08-09-06, 11:07 AM**

This is an example of a shelving filter

These are the filter settings used to create it...

**rlammi** · **08-09-06, 11:39 AM**

Thanks Thomasw ,how do you know were to put the filters? Yours is an example is it close enough for me to use or would I need something different ? and I don't know if you have seen my first graph ,but it almost takes all 12 filters in reqw .Would adding the shelving filter cut down the number of filters I would need in the ower frequencies ? If I am reading this type of filter it will bring the lower frequencies down so there should be less filters needed .I will try and rerun it tonight and input the filters and try and take another reading and post it so everyone can see .Thanks all ,Ron.

**brucek** · **08-09-06, 12:29 PM**

rlammi,

You're getting way off track here.

Without filters, your raw measurement is quite good (as shown below) and in my opinion you don't need many carefully selected filters to correct it. You don't need a shelf filter.

Simply do a raw measurement without any filters in the BFD and REW and then follow step by step the procedure I outlined for you.

In fact you can simply attach your measurement.mdat file and I'll suggest some filters for you to try. It's always better though if you do it and learn yourself....

brucek

**rlammi** · **08-09-06, 12:54 PM**

okay brucek, I will run one more raw graph and then go threw the filter setup that you outlined and go from there. One final question can I use the first raw reading to get the filter readings or should I run another ?Thanks bruce will get the reading the the next day or so .Again many thanks I am finally understanding the process much better now .Ron

**ThomasW** · **08-09-06, 01:23 PM**

Quote:

in my opinion you don't need many carefully selected filters to correct it. You don't need a shelf filter.

I'm certainly not suggesting he needs to copy the filter I posted. It's just an example of how they're made.

Unlike a standard 'portable' sub, IB subs don't naturally roll-off from the acoustic filter created by 'box'. So.....

Using his filter choices; 20hz +8, and 25hz +5, any music or sound effects with significantly low bass will cause the drivers to slam into the formers.

**brucek** · **08-09-06, 01:25 PM**

Quote:

can I use the first raw reading to get the filter readings or should I run another

If you saved it in a xxx.mdat file, then simply use it again to create your filters off-line with REW - no need to take another reading.

Then once you enter your filters into the BFD, take a new raw reading (be sure any filters in REW are shut off) and check the results of your work...

brucek

**brucek** · **08-09-06, 01:27 PM**

Quote:

I'm certainly not suggesting he needs to copy the filter I posted. It's just an example of how they're made.

Unlike a standard 'portable' sub, IB subs don't naturally roll-off from the acoustic filter created by 'box'. So.....

Using his filter choices; 20hz +8, and 25hz +5, any music or sound effects with significantly low bass will cause the drivers to slam into the formers.

Yep, and I completely agree.......

**rlammi** · **08-09-06, 01:47 PM**

Thanks bruecek and thomasw

I will rerun all the filters and take another reading and repost .Thanks for all the patience .

**rlammi** · **08-10-06, 09:10 PM**

First off I would like to say thanks t o everyone involved with this brucek,johnm, sonnie and the shack and to thomasw at the cult (for getting me into the I/B project).

This has really been a learing expierence with the BFD REQW and the building of this subwoofer .One forum led to another forum and there are a great bunch of people on both .I have gotten a lot of help with the filter I was trying onmy own but I wasn't really getting it I kind of do now .So here is my latest graph and it looks pretty good I thought I would need most of the filters to get it to come close to the target sor here it is and I have to thank Thomasw over at the Cult for the settings here it is and I am going to work on another setting of my own to see how I can adjust it for music I need a little more punch .Played the Eagles and some other stuff sounded great but would like a little more punch or I may need to get use to it .As for movies went right to WOTW and sounds awesome .So per the wifes request we are watching KONG tonight .here is the graph again THANKS TO EVERYONE , Ron.

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