Another bloody calculator

[Quentin Jarrell 671]

Im not exactly sure how much as far as port acceleration. (I will be doing Klippel work with different sized ports on high output sub's next spring). But for example my spider pack is roughly 750 grams at one mm. 18,000 grams at 15mm. And about 60,000 grams at 30 mm.

So in terms of the amount of force to accelerate the airspring to xmax it increased greatly when compared to small signal parameters.

[ramteid 17]

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

[ssh 924]

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

You can use the vent mach page for that since it's based on the driver t/s specs, port area, tuning, and power.

Just plug in your current driver's t/s specs, power, enclosure tuning, and enclosure's port area.

Edited October 4, 2012 by stefanhinote

[KyleBrown 121]

Nice work man.

[swift 501]

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

You can use the vent mach page for that since it's based on the driver t/s specs, port area, tuning, and power.

Just plug in your current driver's t/s specs, power, enclosure tuning, and enclosure's port area.

The port Mach page did not work for me. An older one you made I believe works good but this one doesn't show anything when you hit calculate.

[ssh 924]

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

I was talking about if I was just wanting to plug in measurements from an existing box that i have to see what the vent mach would be.

You can use the vent mach page for that since it's based on the driver t/s specs, port area, tuning, and power.

Just plug in your current driver's t/s specs, power, enclosure tuning, and enclosure's port area.

The port Mach page did not work for me. An older one you made I believe works good but this one doesn't show anything when you hit calculate.

I just added some code that'll that automatically scroll down to the bottom after submission, so try it again.

[swift 501]

Doesn't work bro

[ssh 924]

Doesn't work bro

Hmm. Not sure why. Using firefox, or chrome?

[swift 501]

Safari on my IPad and Chrome on my laptop. Neither worked. I'm not sure what to look for. I filled out all spots except vent Mach and hit calculate and it just reloads page, then I fill in every spot and put .045 in the Mach area and hit calculate and same thing.

The other calculator says I will have .04 Mach on 5500 watts and .051 with 11k. I was just curios what this owe says. What does it actually calculate?

[ssh 924]

You have to input the target vent mach, and in numerical format. ie: 40 would be 40 m/s.

It will then return the necessary amount of port area required.

One thing people should consider carefully is what they use for their power number.

Having a 4kw amp, and expecting a full 4kw 24/7 is going to require a ton more port area then really necessary.

Edited October 4, 2012 by stefanhinote

[ramteid 17]

would be nice if it also showed you what the port mach would be of the port size and tuning you choose on the ported enclosure setup or have an added calculator for that.

That's the entire reason for the vent mach page...

Otherwise the ported page would have to ask all the same questions.

true, i just messed around with it until it showed an area around the size of my port. This calculator is awesome, I will be using it a lot.

[ImBob 2]

Got a couple questions Stefan (probably noobie). Target vent mach has suggestions for low, med, high. Is it safe to assume low-med is a safe range to stay?

And also, with it reading like this : Low: 10 ~0.13 Med: 25 ~0.07 High: 45 ~0.13, what does ~0.13, ~0.07, and again ~013 stand for respectively? I thought it'd read something like Low: 10-24 Med: 25-44 High: 45-? Am I just not understanding the unit of measure here? I've put in #'s for a possible box and it shows 31 m/s vent mach. Sound ok? Anything more to consider?

[ssh 924]

Got a couple questions Stefan (probably noobie). Target vent mach has suggestions for low, med, high. Is it safe to assume low-med is a safe range to stay?

And also, with it reading like this : Low: 10 ~0.13 Med: 25 ~0.07 High: 45 ~0.13, what does ~0.13, ~0.07, and again ~013 stand for respectively? I thought it'd read something like Low: 10-24 Med: 25-44 High: 45-? Am I just not understanding the unit of measure here? I've put in #'s for a possible box and it shows 31 m/s vent mach. Sound ok? Anything more to consider?

I updated the page so hopefully it's a little more clear:

Suggestions: Low: 10 m/s, ~0.03 Med: 25 m/s, ~0.07 High: 45 m/s, ~0.13

Low is 10 m/s. Sometimes programs list the vent mach as a percentage or decimal in relation to the speed of sound. So 10 m/s / speed of sound (~340.29) = ~0.03

I don't like to give definitive answers to something that I haven't personally tested, and especially when one size doesn't fit all. Ie: higher vent mach may not be noticeable in one install, but problematic in another.

I will however tell you what I know. WinISD wants it under 0.16 54 m/s, yet I've read from plenty of people that that is way too high, and causes audible port noise. I've also read an article from JBL that suggested 10 m/s for reducing port compression and port noise. My last large install had a vent mach around 20 m/s, and it performed quite well with no audible port noise.

So ultimately it's up to you to do the research, and decide for yourself, all the while taking into consideration your install. Enclosure in trunk?

Another thing to consider is what number your putting in for power. If your amp is rated for 1500watts at blah blah blah it's very unlikely that the driver will ever consistently see that much power, so you could very well do the calculation with 1000watts, or even more likely: even less.

Edited October 31, 2012 by stefanhinote

[nem 2,019]

You can not bump or post in this thread today with out any blood!!!

[ssh 924]

You can not bump or post in this thread today with out any blood!!!

[ImBob 2]

Thanks Stefan! I guess it'll be safer to build with a bit more pot area just to be sure. The reduction in box size is minimal anyway.

[Penguin4x4 1,761]

bloody calculator doesn't sound nearly as cool as bloody murder

BLOODY MURDER BLOODY MURDER BLOODY MURDERBLOODY MURDER BLOODY MURDER BLOODY MURDER BLOODY MURDER BLOODY MURDER

[Sencheezy 689]

free bump

[Shogen 325]

just curious but what does "low" vent mach speed theoretically do to the output? is it not as loud? cause unloading issues? curious is curious

[ssh 924]

just curious but what does "low" vent mach speed theoretically do to the output? is it not as loud? cause unloading issues? curious is curious

If the vent speed is too high than port compression can occur, and depending on how high it is, it can cause audible noise and/or a reduction in output.

[nem 2,019]

just curious but what does "low" vent mach speed theoretically do to the output? is it not as loud? cause unloading issues? curious is curious

If the vent speed is too high than port compression can occur, and depending on how high it is, it can cause audible noise and/or a reduction in output.

Is there a point when it can be too low?

[ssh 924]

just curious but what does "low" vent mach speed theoretically do to the output? is it not as loud? cause unloading issues? curious is curious

If the vent speed is too high than port compression can occur, and depending on how high it is, it can cause audible noise and/or a reduction in output.

Is there a point when it can be too low?

From what I've read I haven't found anything mentioning any limits for too much port area / too low vent speed, but generally it's a moot point because the port length gets longer, and becomes increasingly difficult to fit in the enclosure.

[nem 2,019]

just curious but what does "low" vent mach speed theoretically do to the output? is it not as loud? cause unloading issues? curious is curious

If the vent speed is too high than port compression can occur, and depending on how high it is, it can cause audible noise and/or a reduction in output.

Is there a point when it can be too low?

From what I've read I haven't found anything mentioning any limits for too much port area / too low vent speed, but generally it's a moot point because the port length gets longer, and becomes increasingly difficult to fit in the enclosure.

I have been looking for an answer to that and have not came across anything either. I have read the lower the better and anything below .4 desirable.

[Quentin Jarrell 671]

It needs to be mandatory for people to join this site that they have read at least one of the loudspeaker cookbooks

[nem 2,019]

It needs to be mandatory for people to join this site that they have read at least one of the loudspeaker cookbooks

Can you offer up a little info on this?

I use an old box program that tells me vent noise may occur when the vent is too small.