Learning trail and error WinISD

[JBL 4645]

Cheers pos for the link its freaky funky as well as interesting. Still this is new me, like a new mobile phone is.

So far in the pm I’ve found the driver JBL 2240.

I’m slightly unsure of the data information if, you can point out what is important in the programs features I catch on.

Cheers :)

[Robh3606]

Hello Ashley

When you run the program it gives you flatest response. You can play with enclosure volume and tuning to get a more extended bass response. For example just run a 2235 in the program. I think it comes in around 3-4 cubic ft. Bump the volume up to say 5 cubic ft and drop the tuning to say 30hz. You will see a worthwhile improvement.

You can run multiple syms so you can also compare different woofers in the same or slightly different boxes.

Play around with it

Rob:)

[JBL 4645]

Hello Ashley

When you run the program it gives you flatest response. You can play with enclosure volume and tuning to get a more extended bass response. For example just run a 2235 in the program. I think it comes in around 3-4 cubic ft. Bump the volume up to say 5 cubic ft and drop the tuning to say 30hz. You will see a worthwhile improvement.

You can run multiple syms so you can also compare different woofers in the same or slightly different boxes.

Play around with it

Rob:)

Yeah Rob
But wouldn’t the port size need to be adjusted as well and what of excursion the JBL has 25mm limit before damage, I don’t think in the 13 years I pushed it that far to hearing continues popping sounds.

I’ve entered the inside box sizes roughly to
W: 24.50
H: 40.20
D: 17.00

[pos]

Ashley,

Here is how to do tyo simulate a given spekaer in WinISD.

You cannot enter the dimensions of the box and have the program deduce a volume: you have to enter a box volume and the program will propose you an ideal enclosure dimension (including optional box walls thickness).

This is done in the "Box" section, by clicking on the "box shape button", and then the "optimum" button.

You can then fix some dimensions and click on the others to recalculate them, alwas for the same fixed volume.

So if you want to simulate a box you have you first have to know its volume (the box shape itself has no effect on the simulation). If you don't and does not want to calculate it by hand you can enter an estimation of the volume and then play with the box shape (with the correct wall thickness) and volume back and forth until you find your correct box shape (lots of trial and error).

The same goes for the port dimensions: WinISD does not let you enter port dimension and then calculate the tuning: you have to give it the tuning frequency and port number and diamater, and it will calculate the length.

Beware: find the correct box volume before playing with the port, as it is a factor that influence the port length (for a given tuning and port dimensions, the smaller the box the longer the port).

You cannot simulate dirver excursion in WinISD: you need WinISD Pro for that, but I would advice you to stay with the normal version of WinISD until you are very familiar with it (and both version are complementary anyway).

[pos]

So now a practical example:
your 2240H in 4645 enclosure

The litterature (http://www.jblpro.com/pub/cinema/4645c.pdf) says the box is 8 cu ft (225L, you can change the unit by clicking on it) and the tuning is 25Hz (that is for the 4645c, but I think all version are simular, even if the port dimensions and number vary).

It is supposed to be loaded with a 2245H, and also used some EQ or room placement techniques to bosst its VLF (the first you can only simulate with WinISD Pro, and the later you have to guess or measure in real situation).

Here is a comparison between a 2240 and a 2245 is that box

[pos]

But that only gives you part of the story, as the "gain" section normalize all the drivers to 0dB in the midband.
If you click on the "SPL" section of the window you will see... nothing :(
This section is suppsed to show you the unnormalized response curves, but it needs the sensitivity rating of each drivers to do so.
Unfortunatley the 2240H and 2245H sensitivity where not entered in the factory preset.
You will have to set them yourself: for each driver, click on the "paramters" button on the bottom of the driver window and click on the "SPL" figure.

Should be 95 for the 2245 (http://www.lansingheritage.org/images/jbl/specs/pro-comp/2245/page2.jpg) and 98 for the 2240 (http://www.lansingheritage.org/images/jbl/specs/pro-comp/2240/page2.jpg)

Now the curve should appear in the SPL section.

You can enter different Watt input values in the "Plot" section of the driver window (default to 1W) and see how much SPL you get.
The excursion is not shown but will be the limiting factor for your 2240 in the VLF (6mm vs 8mm for the 2245). You definitely have to protect your driver by using a HP filter under the tuning frequency with your DCX.
You will have to install WinISD Pro to simulate cone excursion as well as different filters/eq effect on it.

[1audiohack]

Hi Ashley;

I don't know if that program will calculate required port area for you or not. Here is Barry's shoot from the hip port area calculator, take the cone area, or Sd in inches and times by Xmax.

Example a 2242 has an Sd of 192 square inches and an Xmax of 0.35 inches for a value of 67.2"

Thats about a 9" diameter round port or 8X8" square port, large enough that it won't saturate at the drivers maximum linear output.

I know it's not LEAP but it works when all you've got is a pocket calculator 'cause your lap tops at home.

[JBL 4645]

Morning, Pos
I see the differences that are marked in
White
Green

Also LOL remember this was a DIY enclosure made back around 1998 before I even knew of this sites existence much less having my own computer.

The box was knocked up roughly to the same size as the dimensions (as we only had broacher) to follow by.

The 2240 was picked up second-hand for £100.00 in an even lousy size box with port hole about 1inch it was made roughly 21inches square, depth roughly 13inchs? Its 13 years ago…

I was playing with different drivers and A & B up till around 3:30am!:blink:

[JBL 4645]

So now a practical example:
your 2240H in 4645 enclosure

The litterature (http://www.jblpro.com/pub/cinema/4645c.pdf) says the box is 8 cu ft (225L, you can change the unit by clicking on it) and the tuning is 25Hz (that is for the 4645c, but I think all version are simular, even if the port dimensions and number vary).

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=44651&stc=1&d=1267856232

It is supposed to be loaded with a 2245H, and also used some EQ or room placement techniques to bosst its VLF (the first you can only simulate with WinISD Pro, and the later you have to guess or measure in real situation).

Here is a comparison between a 2240 and a 2245 is that box

Morning Pos
With some EQ so are you say the difference in the
White 2240 over the
Green 2245 should have an EQ boast PEQ parametric EQ to rise the frequency to come within near distance of the 2245?

Cheers :)

[JBL 4645]

Hi Ashley;

I don't know if that program will calculate required port area for you or not. Here is Barry's shoot from the hip port area calculator, take the cone area, or Sd in inches and times by Xmax.

Example a 2242 has an Sd of 192 square inches and an Xmax of 0.35 inches for a value of 67.2"

Thats about a 9" diameter round port or 8X8" square port, large enough that it won't saturate at the drivers maximum linear output.

I know it's not LEAP but it works when all you've got is a pocket calculator 'cause your lap tops at home.

Morning 1audiohack

You’re talking way over my head with mathematics! It took me a month or so to understand that 89db doesn’t = 178db :o: LOL I not joking this was 20 years ago. I then realized its 89 + 3db = 92db.

As to underlined in you post I have no idea. I know roughly what square feet inches meters is that is (square box dimension scaled to the size like square inches and for every square you add another square box 1inch) Is that not correct?

It’s a good thing I found out in the end, I mean who has ever heard of pair of control 5 outputting 178db! :o: :p

I just need a basis crash coarse to suss this out.

[JBL 4645]

But that only gives you part of the story, as the "gain" section normalize all the drivers to 0dB in the midband.
If you click on the "SPL" section of the window you will see... nothing :(
This section is suppsed to show you the unnormalized response curves, but it needs the sensitivity rating of each drivers to do so.
Unfortunatley the 2240H and 2245H sensitivity where not entered in the factory preset.
You will have to set them yourself: for each driver, click on the "paramters" button on the bottom of the driver window and click on the "SPL" figure.

Should be 95 for the 2245 (http://www.lansingheritage.org/images/jbl/specs/pro-comp/2245/page2.jpg) and 98 for the 2240 (http://www.lansingheritage.org/images/jbl/specs/pro-comp/2240/page2.jpg)

Now the curve should appear in the SPL section.

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=44652&stc=1&d=1267856786

You can enter different Watt input values in the "Plot" section of the driver window (default to 1W) and see how much SPL you get.
The excursion is not shown but will be the limiting factor for your 2240 in the VLF (6mm vs 8mm for the 2245). You definitely have to protect your driver by using a HP filter under the tuning frequency with your DCX.
You will have to install WinISD Pro to simulate cone excursion as well as different filters/eq effect on it.

Morning pos
Hmmm I seem to roughly grasp where you’re going with this post and the differences in the
White 2240 over
Green 2245

I see the large level or hump in the frequency or rather the (steep curve bending over it with some slight modification that you made).

The large bend over at around 90Hz that can be lowered with PEQ filter placed somewhere slightly up the scale at around? 300Hz to lower it down a bit with –db and Q filter?

Between 30Hz and 90Hz there is gap that can be boasted up not sure if it’s between 50Hz with a little +db and Q filter.

Cheers

Edit:

Oh, bugger almost forget! The sub runs with no crossover its only getting the direct LFE.1 track that is filtered off roughly at 120Hz where it starts to cut-off at.

I have limiter on the AVR called (bass peak management) that is variable from (0db down to -30db in 1db steps).

I only have one DCX2496 at present time for the JBL control 5.

[pos]

If you put a 80Hz LP in the picture the difference is less obvious.
At these frequency the room geometry dominate the response, so if you simply put you sub in a corner, and mesure and EQ the reponse (by reducing the peaks, and leaving the dips alone as nothing can be done about them with a single sub) at your listening position you should not worry about these simulated curves.

[JBL 4645]

If you put a 80Hz LP in the picture the difference is less obvious.
At these frequency the room geometry dominate the response, so if you simply put you sub in a corner, and mesure and EQ the reponse (by reducing the peaks, and leaving the dips alone as nothing can be done about them with a single sub) at your listening position you should not worry about these simulated curves.

Morning, pos
The only active crossover I have left is in the bedroom and that I believe has cut-off at around 500Hz not sure about the bottom end?

It’s called a 2WEX its in one of the pictures on one of two threads.

I really need to get another DCX2496 which is long overdue since I was suppose get two or three around 3 years ago that was the plan. sigh I get sidetracked like most others I do. sigh

As for a single sub not sure if you read this thread post http://www.audioheritage.org/vbulletin/showthread.php?p=281508#post281508

It’s located near the bottom of the page. The JBL doesn’t fit in nice where she is in fact any sub, (the left front corner is life sucking bitch on low end response). LOL

So I placed the smaller sub Eltax A12-R behind me and its sharing with the JBL 4645 “DIY” to fill in the gap. Boom is reduced so I get feeling sense low end, boom I get enough of that on Bournemouth yellow bus with the engine purring away in my ears. LOL

Okay so don’t worry about the simulated curves.

Also odd enough I stuck a Pringles can that is about the same diameter as the Eltax port, I stuck the can on the front and its increased the lower end by hmmm, I forget its up +db6 or 8 I think

I’d have to run another frequency sweep. I was thinking of doing the same for the JBL but I don’t have tube at the same diameter or length for that matter.

I’m popping out a around a friends and see if he has any spare plastic drainage tubes, I’ll be back in a few hours time.

Cheers :)




Cheers

[JBL 4645]

Okay I’m back and he hasn’t got a decent drainage pipe! sigh I wanted to try out and idea of placing it on the front of the JBL. Oh, well maybe another day.

Been given this a bit more thought while walking back.