Winisd Question..

[Mr Bojangles 10+ year member]

1). Those who are familiar, when looking at the plot, (the green lines and the one purple one), is it best to end up with a smooth line or roller coaster?

2). The manual talked a little about the -3db and how that is the cut off point. So if the green line hits the purple line at say 25hz, then the speaker will not play much lower than that. right?

Click to read more...

 

[Mr Bojangles 10+ year member]

i know someone knows this stuff..

 

[Mr Bojangles 10+ year member]

edit for question # 2

Say i wanted my box tuned at 34, but when i input all of my measurements and moved my cursor over the plot, 34hz was right on the cutoff line (purple). So would i have to adjust it until i get 34 between the purple and red line? Is between the purple and red line like where the speaker will be loudest?

 

[Mr Bojangles 10+ year member]

bump!

 

[Mr Bojangles 10+ year member]

really need this question answered asap.. thanks

 

[helotaxi 5,000+ posts]

Tuned to 35 Hz is just that. It may not indicate what the actual F3 of the system will be.

In an optimal tuned alignment, you are looking for a flat response with a smooth rolloff. That will give you the most accurate sound out of the system. You can mess with the tuning and get a peak in the response curve which indicates that the sub will accenuate the frequency at the peak.

What you are looking at in the first plot that comes up in WinISD Pro is the response of the setup relative to a 0dB reference (the red line). That reference is the output level of the upper freqs if there was no low pass filter installed. Any peaks are referenced to the 0dB line. F3 (the purple line) is relative to the 0dB line. Look at this plot as volume measured in relation to frequency. The highest peak in the curve is where the box will be the loudest. This may not be at tuning. If the output level at the tuning freq is below the F3 you probably have the box sized or tuned wrong for the sub in question.

As far as the significance of the F3 goes, the plot you are looking at is assuming a listening room large enough that it will not have an effect on the response. Your car is not nearly that big. The effect of your car is to amplify the low frequencies and help he sub fill in the frequencies below the F3. This is espeically noticable with a sealed box where your F3 might be in the 60Hz range or higher but the sub in car is capable of playing well below the audible frequency range.

WinISD is not going to tell you the response you will get from your system in your car. It is only a tool that will let you see a relative change between two setups. You have to e able to interpret what it is telling you for that to mean anything.

What subs are you working with?