Baffle Difraction Response Modeler--applicable to floor standing cab?

[pullshocks]

My project is a 3 way floor stander 35.5x 13 wide x 16.5 deep. The 10" woofer is centered 16" above the floor, the 5" mid is centered 25" above the floor.

Following Paul Carmody's excellent step by step guide, I processed my frd and zma files with response modeler 3.01, including the baffle diffraction response modeler.

It occurs to me that along the bottom of the cab you don't have the 4 pi space like you do along the sides and top. So would the baffle difraction simulator over-estimate the baffle step for the woofer, and maybe even the mid? If so, how should I handle this when it comes to using the files in the Passive Crossover Designer?

[Jeff B.]

My project is a 3 way floor stander 35.5x 13 wide x 16.5 deep. The 10" woofer is centered 16" above the floor, the 5" mid is centered 25" above the floor.

Following Paul Carmody's excellent step by step guide, I processed my frd and zma files with response modeler 3.01, including the baffle diffraction response modeler.

It occurs to me that along the bottom of the cab you don't have the 4 pi space like you do along the sides and top. So would the baffle difraction simulator over-estimate the baffle step for the woofer, and maybe even the mid? If so, how should I handle this when it comes to using the files in the Passive Crossover Designer?

The tool you want to use in the "Baffle Diffraction and Boundary Simulator" available at the link below. It will combine the baffle diffraction with the boundary reinforcement of the floor and the nearby walls. You can export the results as an frd file, then import them into the Response modeler instead of using its built-in tool to add this response to the driver file. Then, you can use this combined file in PCD.

Jeff B.

[pullshocks]

Thanks Jeff, and triple thanks for making those programs available. I sat down last night to work with PCD, and the next thing I knew it was 4:30 AM. I suppose I am getting a bit obsessed too.

[arlis_1957@yahoo.com]

sometimes stoping can derail the train of thought. please share your frd when you get there.

[pullshocks]

Have played around with the Baffle Diffraction and Boundary Simulator a few times now. It looks like it will be beneficial to move the woofer down a couple inches and a slight additional benefit to round the corners

What is really amazing is the room effects. Quite an eye opener. After seeing what the room and placement does to the response, it is actually pretty discouraging. In my case, hard to avoid a huge dip at 250 Hz, but good to be aware of and do some in-room measurements


Question 1--how do I import or load my raw FRD into the program for processsing?

Question 2--for purposes of what you work with in PCD do you suggest actually using the FRD with the combined baffle, boundary, and room effects?

Question 3--how would I go about posting the FR graphs as Arlis_1959 asks?

Question 4--in view of the 15-20 db of gain at low frequencies, are sealed cabinets actually a better way to go to end up with a flat response in a sub optimum room? (My wife is OK with big speakers, but not very flexible about where they would be positioned in our living room.) I know, "it depends..."

[pullshocks]

Bump

[diy speaker guy]

Have played around with the Baffle Diffraction and Boundary Simulator a few times now. It looks like it will be beneficial to move the woofer down a couple inches and a slight additional benefit to round the corners

What is really amazing is the room effects. Quite an eye opener. After seeing what the room and placement does to the response, it is actually pretty discouraging. In my case, hard to avoid a huge dip at 250 Hz, but good to be aware of and do some in-room measurements

And that's only half the story. Once you add in the final 3 boundaries in the room (all of which are parallel with the first 3) and the associated room modes things start to look really ugly.

Question 1--how do I import or load my raw FRD into the program for processsing?

I don't have PCD in front of me right now but there's a big button up near the top on the right side that says something like "Load FRD" or "Import FRD" or something like that for each driver. In response modeller, the button is in a slightly different location.

Question 2--for purposes of what you work with in PCD do you suggest actually using the FRD with the combined baffle, boundary, and room effects?

You can use whatever you like depending on your situation. I almost always model the baffle effects and floor bounce but I do not include any of the other boundaries or the room gain.

Question 3--how would I go about posting the FR graphs as Arlis_1959 asks?

Either attach a file to your post or host the file somewhere else and link to it.

Question 4--in view of the 15-20 db of gain at low frequencies, are sealed cabinets actually a better way to go to end up with a flat response in a sub optimum room? (My wife is OK with big speakers, but not very flexible about where they would be positioned in our living room.) I know, "it depends..."

Depends on the situation. Some rooms have very large amounts of room gain. A concrete walled basement is a good example. Other rooms have almost no room gain. A good example would be an open concept home, heavily carpeted and furnished with thin siding walls. The key is to match the sub's response to the room's effects so that it sums flat. If you are not designing around a particular room you can try to shoot for some kind of average, or just do whatever you want.

[pullshocks]

OK I now see the "import baffle & room data" button in Response Modeler.

Thank you

[arlis_1957@yahoo.com]

depending on where you are crossing the woofer, you may be able to get it closer to the floor for less floor bounce. move it down and look at the results.
i use photobucker and its very easy to put pics in a post.