I guess I should start by saying I think I am over my head.😕 I'm not even sure if what I want to do is possible or worth it. If the answer is no to either just tell me and I'll stop right now.
I have two old subwoofers sitting in my garage doing nothing. I am intrigued by the idea of using them in my home theater system. Am I wrong in assuming that if I buy an amp made for home use that I can use it to power these? If I can, then whats the difference between a regular power amp and a subwoofer amp? The latter seems to be more expensive. But if all I need is the crossover, can't I just use the AVR?
Now for the subs. I know there are differing opinions on these, but I bought them when I was young. I've got two Volfenhag ZX-4712 DVC subs. I'd like to have them in two separate boxes; one on either side of the entertainment center. Possibly tuned differently if I go with ported boxes, or one sealed and one ported. I don't want to get into a complicated design.
Here's all the specs I could find on the subwoofers:
Volfenhag ZX-4712 DVC
4 ohm DVC
500 RMS
20Hz-1.1kHz freq. range
Fs 30Hz
Qts 0.526
Qes 0.614
Qms 7.698
Vas 56L
Xmax 16mm
SPL 89.58 dB
Sd 0.0491
Re 3.2 ohms
mount depth 160mm
mount dia. 282mm
I tried my hand at WinISD but quickly got lost. I entered all the values above but when I went to start a new project it says "Driver data fails integrity check". I added it anyway and started playing around. The EBP (if the values are correct) shows 48.9 which I understand to mean that either a sealed or ported box can be used. If I am looking at this right then the sealed box has a cutoff point at 37.66Hz, which is higher than I was hoping for.
If what I want to do is possible, would anyone be willing to help me figure out the best boxes to build? The outer width and length cannot exceed 20x22. The height can be as high as 28".
Thanks in advance!
I have two old subwoofers sitting in my garage doing nothing. I am intrigued by the idea of using them in my home theater system. Am I wrong in assuming that if I buy an amp made for home use that I can use it to power these? If I can, then whats the difference between a regular power amp and a subwoofer amp? The latter seems to be more expensive. But if all I need is the crossover, can't I just use the AVR?
Now for the subs. I know there are differing opinions on these, but I bought them when I was young. I've got two Volfenhag ZX-4712 DVC subs. I'd like to have them in two separate boxes; one on either side of the entertainment center. Possibly tuned differently if I go with ported boxes, or one sealed and one ported. I don't want to get into a complicated design.
Here's all the specs I could find on the subwoofers:
Volfenhag ZX-4712 DVC
4 ohm DVC
500 RMS
20Hz-1.1kHz freq. range
Fs 30Hz
Qts 0.526
Qes 0.614
Qms 7.698
Vas 56L
Xmax 16mm
SPL 89.58 dB
Sd 0.0491
Re 3.2 ohms
mount depth 160mm
mount dia. 282mm
I tried my hand at WinISD but quickly got lost. I entered all the values above but when I went to start a new project it says "Driver data fails integrity check". I added it anyway and started playing around. The EBP (if the values are correct) shows 48.9 which I understand to mean that either a sealed or ported box can be used. If I am looking at this right then the sealed box has a cutoff point at 37.66Hz, which is higher than I was hoping for.
If what I want to do is possible, would anyone be willing to help me figure out the best boxes to build? The outer width and length cannot exceed 20x22. The height can be as high as 28".
Thanks in advance!
You seem to be on track. I didn't get any error. I didn't plug in the Sd number though as it looked crazy.
Run a vented box calc, you can get down to 20hz in a 134L box. Your dimensions look close, but I don't work with inches. One of the pop-up windows says 134L and you can delete that and put in what you have. The graph will then adjust.
I reckon your there. The hard bit is converting to standardised units.
Run a vented box calc, you can get down to 20hz in a 134L box. Your dimensions look close, but I don't work with inches. One of the pop-up windows says 134L and you can delete that and put in what you have. The graph will then adjust.
I reckon your there. The hard bit is converting to standardised units.
Curious where you found it has 16 mm Xmax as these folks used only 5 mm in sims: Volfenhag ZX4712 DVX 12″ Subwoofer Thiele/Small – AmpsLab
The published specs are bogus in that Qes, Qms sums to 0.569 Qts, not 0.526 plus ideally need to add a 1/2 ohm for wiring, bumping it up to 0.65 Qts' [Qts + Rs]: HiFi Loudspeaker Design
Their series measured specs after sufficient break-in aren't even remotely close enough [changed to parallel]:
Fs 45.76 Hz
Qts 1.39
Qes 1.75
Qms 6.76
Vas 33.78 L
Xmax 5 mm?
SPL 89.58 dB
Sd 0.0558.65
Re 3.35 ohms
Le 2.59 mH
Rg 0.5 ohm
Really need to measure yours, otherwise assume these and recommend some form of TL + DSP to deal with such a tiny Vas, weak motor, so how big in HxWxD is available?
GM
The published specs are bogus in that Qes, Qms sums to 0.569 Qts, not 0.526 plus ideally need to add a 1/2 ohm for wiring, bumping it up to 0.65 Qts' [Qts + Rs]: HiFi Loudspeaker Design
Their series measured specs after sufficient break-in aren't even remotely close enough [changed to parallel]:
Fs 45.76 Hz
Qts 1.39
Qes 1.75
Qms 6.76
Vas 33.78 L
Xmax 5 mm?
SPL 89.58 dB
Sd 0.0558.65
Re 3.35 ohms
Le 2.59 mH
Rg 0.5 ohm
Really need to measure yours, otherwise assume these and recommend some form of TL + DSP to deal with such a tiny Vas, weak motor, so how big in HxWxD is available?
GM
Thank you both for the very quick responses. The specs I listed (except for xmax) were from the manufacture according to the same post you linked above. I didn't pay close enough to what they were using for xmax. However, I found 3 other websites where people all reported 16mm so I just used that.
The numbers you posted are drastically different. I figured some of the manufacture specs were incorrect, but not by that much. I will play around again with WinISD after work.
Also, by TL you mean transmission line? Doesn't that typically give a higher roll off? Also more complex to build.
The numbers you posted are drastically different. I figured some of the manufacture specs were incorrect, but not by that much. I will play around again with WinISD after work.
Also, by TL you mean transmission line? Doesn't that typically give a higher roll off? Also more complex to build.
0.0491 would be fine if it is square meters - it equates to 491sq cm (in more common units), about right for a nominal 12" driver with a wide surround.
Just want to make sure I have this correct? The values found at AmpsLab are all real world measured values? I am assuming they used 5mm xmax as a default value, since everything I have been able to find online says that's what you should assume if the manufacture doesn't list it.
I entered all of those values from AmpsLab and I still got a failed integrity check message when loading in WinISD. I went ahead and entered some projects anyway. If this is correct then I am not really impressed with the low end in a sealed box. The best I could come up with was a vented box tuned to 23Hz. There is a dip at about 27Hz but it's above the -3dB cutoff at about -1.54dB. This is a 6.5cuft box with 3" vent at 3.54" length. Does this all check out?
I entered all of those values from AmpsLab and I still got a failed integrity check message when loading in WinISD. I went ahead and entered some projects anyway. If this is correct then I am not really impressed with the low end in a sealed box. The best I could come up with was a vented box tuned to 23Hz. There is a dip at about 27Hz but it's above the -3dB cutoff at about -1.54dB. This is a 6.5cuft box with 3" vent at 3.54" length. Does this all check out?
An externally hosted image should be here but it was not working when we last tested it.
You're welcome!
OK, though might want to measure its max limit [Xmech], which will be somewhat longer.
Indeed!, though sadly it's typical of many in the mobile audio market; prosound and a relatively few in home/DIY markets are 'close enough'.
Yes, depends on the type of TL; mostly what 'we' recommend around here are relatively tall [3.5-6 ft internally] with a vent [usually tuned for flattest response], then damped to 'taste' [aka MLTL].
With a ~1.39 Qts though, a well damped open bottom tube is often better overall.
All that said, at 28" o.d. longest dim. you'll have to fold it at least once, so a little more complex, but no angle cuts involved. The only ?? is will ~5.5 ft^3 net be acoustically big enough to get the most out of such a weak motor.
BTW, are you using the current version of WinISD as I've noticed some others are using older, less accurate/feature filled ones? WinISD - Linearteam
GM
OK, though might want to measure its max limit [Xmech], which will be somewhat longer.
Indeed!, though sadly it's typical of many in the mobile audio market; prosound and a relatively few in home/DIY markets are 'close enough'.
Yes, depends on the type of TL; mostly what 'we' recommend around here are relatively tall [3.5-6 ft internally] with a vent [usually tuned for flattest response], then damped to 'taste' [aka MLTL].
With a ~1.39 Qts though, a well damped open bottom tube is often better overall.
All that said, at 28" o.d. longest dim. you'll have to fold it at least once, so a little more complex, but no angle cuts involved. The only ?? is will ~5.5 ft^3 net be acoustically big enough to get the most out of such a weak motor.
BTW, are you using the current version of WinISD as I've noticed some others are using older, less accurate/feature filled ones? WinISD - Linearteam
GM
Yes, I am using 0.7.0.950 downloaded just a few days ago.
A tube seems like something that would be difficult for an amateur to build as a first time cabinet. I'd like have to pay someone to build it, no?
See my post above and the picture I posted from WinISD. Am I using it correctly? Any thoughts on what I came up with as far as the regular vented box?
With a Q of around 1.5, I'd be exploring "open baffle" bass designs. But bear in mind the overall output of an OB design can be significantly less than other designs.
😀A tube need not be round, just acoustically long enough for the needs of the app, so 'we' [including many first time woodworkers] normally make them tall rectangular boxes or folded with dividers to create the long 'tube' in your case.
The link won't load for me.
GM
Ah, I see. In that case, yes, I plan on building a rectangle and the height will have to be the longest dimension due to restrictions on available space. I went back and did calculations with both the manufacturers TS parameters and the measured ones found on AmpLabs. I'm not at my computer right now but I think I came up with a vented box tuned to 26Hz with a 4" vent that works well with either set of parameters. Think I'll just try it out and if it doesn't work I'll have some more wood for the fire pit 🙂