[rxh0272]

Hi Guys:

can someone please help me? What do we do, apply, when we never a sub woofers resonate frequency?

when designing the subwoofer enclosure, do I need to tune it to make sure I am above the resonant frequency, below the resonant frequency, or what?

And what does the cars resonant frequency have to do with the subwoofer resonant frequency and enclosure design? Sealed/ported?

is it worth me buying the least expensive equipment to determine the resonant frequency of the car in order to properly design the subwoofer enclosure and choose the proper subwoofer?

Thank You,
Rob

 

[daloudin]

The resonant frequency of the woofer is the point at which the driver naturally rolls off below that point. It used to be that you had to have a sub with an Fs (resonant frequency) that was really low in order to play true sub bass but with the abundance of wattage and dsp/eq available now you can add enough boost below Fs to compensate. Once you add in cabin gain it's usually not necessary anyway.

The car will have multiple resonant frequencies as every pair of parallel surfaces will have one frequency and then there's the helmholtz resonance (the low frequency thrumming you get when you only open one window - it's the sound that a bottle makes when you blow across the opening) and panel resonance and the list goes on...

The most important resonant frequency is the box you put the Subwoofer in... the wrong box can ruin the best Sub and even an expensive box that's not the right size or design is equally as bad. Any good sub will list Thiele Small parameters which can be entered in to a free box design program (WinISD, BassBox, etc) to give you good idea of what box the driver needs.

Then you also have to use the right kind of sub in the right kind of design: sealed, ported, passive radiator, bandpass, infinite baffle, etc. Each sub has a preferred design but some work equally well in multiple designs. Ported is louder but if it's not tuned correctly then it's boomy and peaks without much bass extension since it rolls off faster below tuning. Sealed rolls off the slowest (well actually infinite baffle is slowest but that's not really an enclosure unless you count the trunk as the enclosure) for the best low bass extension. But you can design a ported enclosure that's capable of going just as low with the right sub...

Clear as mud?

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[rxh0272]

The resonant frequency of the woofer is the point at which the driver naturally rolls off below that point. It used to be that you had to have a sub with an Fs (resonant frequency) that was really low in order to play true sub bass but with the abundance of wattage and dsp/eq available now you can add enough boost below Fs to compensate. Once you add in cabin gain it's usually not necessary anyway.

The car will have multiple resonant frequencies as every pair of parallel surfaces will have one frequency and then there's the helmholtz resonance (the low frequency thrumming you get when you only open one window - it's the sound that a bottle makes when you blow across the opening) and panel resonance and the list goes on...

The most important resonant frequency is the box you put the Subwoofer in... the wrong box can ruin the best Sub and even an expensive box that's not the right size or design is equally as bad. Any good sub will list Thiele Small parameters which can be entered in to a free box design program (WinISD, BassBox, etc) to give you good idea of what box the driver needs.

Then you also have to use the right kind of sub in the right kind of design: sealed, ported, passive radiator, bandpass, infinite baffle, etc. Each sub has a preferred design but some work equally well in multiple designs. Ported is louder but if it's not tuned correctly then it's boomy and peaks without much bass extension since it rolls off faster below tuning. Sealed rolls off the slowest (well actually infinite baffle is slowest but that's not really an enclosure unless you count the trunk as the enclosure) for the best low bass extension. But you can design a ported enclosure that's capable of going just as low with the right sub...

Clear as mud?

Sent from my SM-G965U using Tapatalk

Thanks for the reply.
So, when using winISD Pro to simulate subs (JL 10W3v3, RF P3-10) I can tune the box to whatever Hz I want?
I was looking at the peaks and adjusting size, port length,etc. trying to get it not peaky.

 

[daloudin]

WinISD will give you optimum tuning right out of the gate. Then if you want to fiddle with things like port tuning or box size you can but avoid doing the click and drag thing as it moves way too much at a time and it's really hard to control. But yes, you can change the tuning frequency of the box or port for vented and changing the size in sealed will change the Q. The lower the Q (optimum is 0.707) to go towards infinite baffle and a slower low frequency roll off, raise the Q to increase rolloff, power handling and create an increase in response above the tuning point.

You "can" model in-cabin gain but it's all just an estimate based on math.

Sent from my SM-G965U using Tapatalk

 

[LBaudio]

Usually we tune boxes at or a bit above FS of the driver in case of ported enclosures. The driver will ofcourse play under own Fs, but with added distortion.
In case of sealed it will play to Fo since we usually dont use subsonic filter with sealed enclosures.

 

[rxh0272]

WinISD will give you optimum tuning right out of the gate. Then if you want to fiddle with things like port tuning or box size you can but avoid doing the click and drag thing as it moves way too much at a time and it's really hard to control. But yes, you can change the tuning frequency of the box or port for vented and changing the size in sealed will change the Q. The lower the Q (optimum is 0.707) to go towards infinite baffle and a slower low frequency roll off, raise the Q to increase rolloff, power handling and create an increase in response above the tuning point.

You "can" model in-cabin gain but it's all just an estimate based on math.

Sent from my SM-G965U using Tapatalk

Thanks a lot for the input.
My TS parameter notes r home.
If I recall, .707 is typically used. .6 is kind of middle of the road. .5 is lot and can be too low.

So, when I forst enter the parameters and load it as a project, whatever is in there is the optimum performance that winISD Pro calculated, right?

But, for the P3-10 it made something like a 23 cubic foot box. And for the JL is was something lime 9 cubes.

So, basically it’s best to only manually modify the box volume and let winISD calculate the rest, but make sure Q remains at/around .707, correct?

Is winISD Pro simulation accurate in the real world?

 

[Destarah]

I find it helpful to compare the recommendation from WinISD to the recommended box size from the manufacturer. You can make a copy of the project and then modify the size and tuning frequency to see how things change. Here is an example of the P3-10 in WinISD recommended ported compared to RF recommended:

As you can see, RF (red) is louder above 35Hz (1.4cuft box, 40Hz tuning frequency) but below 35Hz the WinISD option crushes (due to the 20Hz tuning frequency and 3.3cuft box) 20dB louder at 20Hz. If you are looking for significantly higher output at 45Hz then the RF option is great lol.
Full list of differences:

Hope this helps

 

[daloudin]

Thanks a lot for the input.
My TS parameter notes r home.
If I recall, .707 is typically used. .6 is kind of middle of the road. .5 is lot and can be too low.

So, when I forst enter the parameters and load it as a project, whatever is in there is the optimum performance that winISD Pro calculated, right?

But, for the P3-10 it made something like a 23 cubic foot box. And for the JL is was something lime 9 cubes.

So, basically it’s best to only manually modify the box volume and let winISD calculate the rest, but make sure Q remains at/around .707, correct?

Is winISD Pro simulation accurate in the real world?

In theory, yes. WinISD will give you optimum but if it said 23ft³ then start by looking at the parameters input for that driver. Specifically look at the units for each one and make sure they are correct. Things like VAS in liters vs ft³ can throw WinISD off course in a big way. Big M vs little m for things like motor force etc. Check every one of the inputs, leave no stone unturned. Click on the units label and it will increment through the available options.

PA woofers with accordian cloth surrounds and extremely high efficiency usually model in the 20+ ft³ but not a sub designed for use in a car. (I'm not near my laptop to run some quick models rn.)

Then there are size limitations due to the car. You get a sub that models to 0.7 in a 1ft³ box but the space for the factory sub only allows for a maximum of 0.7ft³ so the box Q goes up and you compensate with eq in the dsp. But ideally, you make the box as flat as possible (for SQ) and then use dsp to take care of peaks and valleys caused by the cabin.

Going below 0.5 means you're getting in to infinite baffle territory and wasting space with very little return.

Sent from my SM-G965U using Tapatalk

 

[rxh0272]

I find it helpful to compare the recommendation from WinISD to the recommended box size from the manufacturer. You can make a copy of the project and then modify the size and tuning frequency to see how things change. Here is an example of the P3-10 in WinISD recommended ported compared to RF recommended:
View attachment 290128

As you can see, RF (red) is louder above 35Hz (1.4cuft box, 40Hz tuning frequency) but below 35Hz the WinISD option crushes (due to the 20Hz tuning frequency and 3.3cuft box) 20dB louder at 20Hz. If you are looking for significantly higher output at 45Hz then the RF option is great lol.
Full list of differences:
View attachment 290129

Hope this helps

Thanks Destarah:

What version of winISD are you using? I'm using the latest version of winISD Pro alpha. But, I'm not sure I really know how to use it, so I. am reading the Help contents top-to-bottom

--I'm trying to go as low as the sub can with good output. The P3 was just a starting point. In another forum, we narrowed it down to a 10" because of size constraints. However, I could always double the size by using the size of the entire floor. Right now, I took the floor area and divided it by 2, and plan to put the box on the left side of the trunk. This will save more trunk room. down firing anyway.

--Is there any other recommendations you have for a better sub that can go low?
--Been modeling some JL sub, but expensive; yet, easier to tune.

 

[daloudin]

Thanks Destarah:

What version of winISD are you using? I'm using the latest version of winISD Pro alpha. But, I'm not sure I really know how to use it, so I. am reading the Help contents top-to-bottom

--I'm trying to go as low as the sub can with good output. The P3 was just a starting point. In another forum, we narrowed it down to a 10" because of size constraints. However, I could always double the size by using the size of the entire floor. Right now, I took the floor area and divided it by 2, and plan to put the box on the left side of the trunk. This will save more trunk room. down firing anyway.

--Is there any other recommendations you have for a better sub that can go low?
--Been modeling some JL sub, but expensive; yet, easier to tune.

Check out the Dayton HO-44 - Really small box requirements and you can put 2 of them in 3 ft³ ported around 22-24hz for the same price as one more expensive sub.

Sent from my SM-G965U using Tapatalk

 

[rxh0272]

In theory, yes. WinISD will give you optimum but if it said 23ft³ then start by looking at the parameters input for that driver. Specifically look at the units for each one and make sure they are correct. Things like VAS in liters vs ft³ can throw WinISD off course in a big way. Big M vs little m for things like motor force etc. Check every one of the inputs, leave no stone unturned. Click on the units label and it will increment through the available options.

PA woofers with accordian cloth surrounds and extremely high efficiency usually model in the 20+ ft³ but not a sub designed for use in a car. (I'm not near my laptop to run some quick models rn.)

Then there are size limitations due to the car. You get a sub that models to 0.7 in a 1ft³ box but the space for the factory sub only allows for a maximum of 0.7ft³ so the box Q goes up and you compensate with eq in the dsp. But ideally, you make the box as flat as possible (for SQ) and then use dsp to take care of peaks and valleys caused by the cabin.

Going below 0.5 means you're getting in to infinite baffle territory and wasting space with very little return.

Sent from my SM-G965U using Tapatalk

Happy Sunday. Thanks for the input.
I still do not fully understand Q. I'm readying up on it.
--The recommended box size, vented for a P3D4-10 is 3.019ft³; I have 1.638ft³ before sub+port displacement subtracted.
I checked all the values, and they are correct, except Vd is 0.02 ft³, but the sub, in this case a P3D4-10, is 0.074, and when I try and change it, WinISD says to check values/doesn't let me save.

--I have 1.638 ft³ before sub and port displacement. When I use winISD Pro, does the program automatically subtract the port displacement from the internal volume?

 

[rxh0272]

In theory, yes. WinISD will give you optimum but if it said 23ft³ then start by looking at the parameters input for that driver. Specifically look at the units for each one and make sure they are correct. Things like VAS in liters vs ft³ can throw WinISD off course in a big way. Big M vs little m for things like motor force etc. Check every one of the inputs, leave no stone unturned. Click on the units label and it will increment through the available options.

PA woofers with accordian cloth surrounds and extremely high efficiency usually model in the 20+ ft³ but not a sub designed for use in a car. (I'm not near my laptop to run some quick models rn.)

Then there are size limitations due to the car. You get a sub that models to 0.7 in a 1ft³ box but the space for the factory sub only allows for a maximum of 0.7ft³ so the box Q goes up and you compensate with eq in the dsp. But ideally, you make the box as flat as possible (for SQ) and then use dsp to take care of peaks and valleys caused by the cabin.

Going below 0.5 means you're getting in to infinite baffle territory and wasting space with very little return.

Sent from my SM-G965U using Tapatalk

Hello:

So, I checked all the values, and they are all correct values and measurements, except Vd.
--I believe Vd is the driver displacement? sorry, haven't done a build since about 1998.
If Vd is the driver, then it's supposed to be 0.074'³. But, when i change it and try and save, winISD gives an error message.

 

[Destarah]

I checked all the values, and they are correct, except Vd is 0.02 ft³, but the sub, in this case a P3D4-10, is 0.074, and when I try and change it, WinISD says to check values/doesn't let me save.

Follow the instructions found here when entering driver parameters ... it's best to let WinISD calculate as many values as possible based on minimum input.

I have 1.638 ft³ before sub and port displacement. When I use winISD Pro, does the program automatically subtract the port displacement from the internal volume?

WinISD is not calculating the net volume, it is telling you what the net volume needs to be. Figure on 0.3cuft for a 10" sub and port combined. So your volume in WinISD should be 1.3cuft

 

[rxh0272]

Check out the Dayton HO-44 - Really small box requirements and you can put 2 of them in 3 ft³ ported around 22-24hz for the same price as one more expensive sub.

Sent from my SM-G965U using Tapatalk

I have used Dayton

Follow the instructions found here when entering driver parameters ... it's best to let WinISD calculate as many values as possible based on minimum input.



WinISD is not calculating the net volume, it is telling you what the net volume needs to be. Figure on 0.3cuft for a 10" sub and port combined. So your volume in WinISD should be 1.3cuft

OK. So basically just use my calculated net after subtracting out port + sub displacement.
The link does go to anything.

Follow the instructions found here when entering driver parameters ... it's best to let WinISD calculate as many values as possible based on minimum input.



WinISD is not calculating the net volume, it is telling you what the net volume needs to be. Figure on 0.3cuft for a 10" sub and port combined. So your volume in WinISD should be 1.3cuft

OK. So basically just use my calculated net after subtracting out port + sub displacement.
The link does not go to anything. Says that the forum is empty

 

[daloudin]

The order of entering in driver data is also in the Help document in WinISD:
Cut and pasted from WinISD Help document.
The suggested procedure for entering driver parameters is following (check first that "Auto calculate unknowns" option is checked):

1. Enter Mms and Cms

This gives fs. If either is not available, then enter fs and other parameter.

2. Enter Sd, Bl and Re

Now, you should get all but Qms (and Qts), Vas. Please note that Vas may not match exactly what is specified by manufacturer, because exact value of Vas depends on environmental parameters. See FAQ.

3. Enter Rms or Qms.

Either one will do, although I tend to prefer Qms over Rms, because it can usually be measured in driver measurement procedures.

4. Enter Hc, Hg and Pe.

If Hc or Hg or either is available, then enter Xmax and optionally either Hc or Hg if available.

5. Enter number of voicecoils.

This procedure is most accurate. Also note that it also calculates true SPL (1W/1m) value. So it might not match the marketing SPL value, which is generally somewhat vague. Not in all cases, though.

6. Correct Znom, if necessary.

If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.

Equivalently, you can check for Bl by entering:

Qes, Fs, Mms or Cms and Re (for desired connection mode).

If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.

Like in Driver-tab in project window, you'll probably noticed the driver icon in bottom of the driver editor window. you can drag the driver object into some project by just dragging the icon.

 

[daloudin]

Hello:

So, I checked all the values, and they are all correct values and measurements, except Vd.
--I believe Vd is the driver displacement? sorry, haven't done a build since about 1998.
If Vd is the driver, then it's supposed to be 0.074'³. But, when i change it and try and save, winISD gives an error message.

Vd is calculated Displacement based on Sd (Cone Area) multiplied by Xmax.

 

[rxh0272]

The order of entering in driver data is also in the Help document in WinISD:
Cut and pasted from WinISD Help document.
The suggested procedure for entering driver parameters is following (check first that "Auto calculate unknowns" option is checked):

1. Enter Mms and Cms

This gives fs. If either is not available, then enter fs and other parameter.

2. Enter Sd, Bl and Re

Now, you should get all but Qms (and Qts), Vas. Please note that Vas may not match exactly what is specified by manufacturer, because exact value of Vas depends on environmental parameters. See FAQ.

3. Enter Rms or Qms.

Either one will do, although I tend to prefer Qms over Rms, because it can usually be measured in driver measurement procedures.

4. Enter Hc, Hg and Pe.

If Hc or Hg or either is available, then enter Xmax and optionally either Hc or Hg if available.

5. Enter number of voicecoils.

This procedure is most accurate. Also note that it also calculates true SPL (1W/1m) value. So it might not match the marketing SPL value, which is generally somewhat vague. Not in all cases, though.

6. Correct Znom, if necessary.

If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.

Equivalently, you can check for Bl by entering:

Qes, Fs, Mms or Cms and Re (for desired connection mode).

If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.

Like in Driver-tab in project window, you'll probably noticed the driver icon in bottom of the driver editor window. you can drag the driver object into some project by just dragging the icon.

Thank you much daloudin!

I found it in the Help section. I am basically reading the entire contents top-down. Haven't designed/built a system since 1998, and have to catch up.

I entered the parameter again for the JL 10W0v3-4 (Just one of the subs I have loaded to model).

I had to find the parameters because the manufacturers don't always put the values on their website/manuals. So found www.loudspeakerdatabase.com, which has all the parameters missing from JL's website.

So I reentered the parameters in the correct order and tabbed through it. I then checked my previous W0v3-4 project and opened a new project using the correct parameters and sequence. I then opened the parameters box and compared. Result: The values are different! Some not by much, and some are the same. BUT, winISD didn't take the new overwritten parameters and change the previous project, so I need to start anew.

Not a big deal.

The 10W0v3-4: in ported, to get it tuned lower, the sub can only handle about 90w to prevent over excursion. The box is small: 1.3 cubic feet.

It's a starting point, but I need to find a sub that functions in 1.3 and get low and loud, but still has extension (?) to play at low-moderate power and sound good. My last build, could only hear the sub at moderate-high levels, but mostly high.

Alright. I am also reading Introduction to Loudspeaker Design by John L. Murphy to add to my knowledge.

 

[Destarah]

The link does go to anything.

Sorry about that, didn't realize I had created a bookmark in Chrome that pointed to the help file on my hard drive lol ... daloudin pasted the same info I was attempting to link to.

he 10W0v3-4: in ported, to get it tuned lower, the sub can only handle about 90w to prevent over excursion.

Especially when using a ported box, you need to add a high-pass filter in WinISD to simulate the subsonic filter you would need in real life. Put in the max RMS power under the Signal tab, then switch over to Excursion plot and add a 4th order LW high-pass filter at 20Hz ... if that doesn't get you under Xmax, keep increasing the frequency until it does.

 

[daloudin]

Without getting real spendy (like $400 for a Morel Ultimate) the only 10" Sub that I know of that will work ported that small AND go fairly deep is the Dayton HO-4 (not the 44 it needs a bigger box) and the HO-4 (Single Voice Coil) actually would work with two of them in 1.3 cuft ported at 29.5Hz. See screenshots from WinISD (Note the Excursion has a 20Hz LR24 HP Filter added) below and note that the f3 is 34Hz (10" is red). You could do one 12 HO-44 in that size box and move the f3 down to 30Hz (12" is green) but with 3db less SPL at the same 1200 Watts.

Doubt you would be able to tell the difference once you got them installed with cabin gain. One 12 or 2 x 10s... probably more of an aesthetic choice than anything.

 

[rxh0272]

Sorry about that, didn't realize I had created a bookmark in Chrome that pointed to the help file on my hard drive lol ... daloudin pasted the same info I was attempting to link to.



Especially when using a ported box, you need to add a high-pass filter in WinISD to simulate the subsonic filter you would need in real life. Put in the max RMS power under the Signal tab, then switch over to Excursion plot and add a at 20Hz ... if that doesn't get you under Xmax, keep increasing the frequency until it does.

Sorry about that, didn't realize I had created a bookmark in Chrome that pointed to the help file on my hard drive lol ... daloudin pasted the same info I was attempting to link to.



Especially when using a ported box, you need to add a high-pass filter in WinISD to simulate the subsonic filter you would need in real life. Put in the max RMS power under the Signal tab, then switch over to Excursion plot and add a 4th order LW high-pass filter at 20Hz ... if that doesn't get you under Xmax, keep increasing the frequency until it does.

I changed the filter settings. Now: 300w signal @1.3 ft3 box tuned to 31Hz, ported with circular 4" port, 23" long, 111.720 SPL @ 53.39Hz, and is under the excursion limit with HPF set to 35Hz.
--But the graph looks like crap to me. Am I wrong?
--I'd like to find a sub that fits and can tune lower. I suppose it will be one at at a time.