[rodsprit]

Hello!

I have been lurking around on many different forums for half a year now.. Finally I can get started on my sonosub project.

Will either go with the CSS SDX15 or the AE AV15-X..
Will be making two of these, perhaps three. My dad got interested when I told him about this. hehe.

I'm making them for my home theatre. But I also listen to alot of music on this system.
The ports will be flared.

Here is a drawing for the sonosub.


And in sonosub.exe



I have some questions.
1: Is this looking good? Are there anything you would change to give better performance?
2: How should I power them? Should I get two Behringer EP2500?
3: Do I need a highpass filter?
4: Whats the air velocity going to be through the port? I really don't want to have any chuffing noise..

Tried the WinISD Pro to calculate things myself, but I can't figure out this program.. It's a little complicated.

-
Dan.

 

[SteveCallas]

If you build three of these, I wouldn't worry about port noise or a high pass filter. I don't have this modeled, but from memory with that driver I'm thinking you would be better served increasing the volume to ~300 liters.

Actually, I found that Mike had modeled the SDX in another thread and it appears ~400 liters is ideal.

 

[rodsprit]

Will be building two of them to use in my ht. Can't really go for 400L, like the women would say, it's just too big.

 

[ironglen]

Typically 2 or 4 drivers are used rather than 3 because of amp cost/configuration. If volume is an object, you might want to model both drivers or ask manufacturer to see if one is better suited to your maximum allowable volume. If you're going sono though, realize it takes no extra floorspace and if you have standard 8' ceilings or greater...good luck-with the waf that is:whistling::bigsmile:

 

[ironglen]

Have you considered sealed? Much smaller and you'll have two drivers. I've got an 18" mal x sono with an ep2500 equivalent and, well, my buddy visited last week and said it was:rofl: too loud! :rofl::rofl::hsd: My wife said is was great!!!:rofl::rofl::rofl: We have a room that acts really big due to three doorways, a staircase, and an open wall to downstairs-of course not trying to dissuade you, just to get what you need:bigsmile:

 

[rodsprit]

I think some you misunderstood. 1tube 1driver. 1more tube and one more driver. Two towers in my livingroom.. Making two tubes, and the thing I mentioned earlier was my DAD got excited about this and he wanted to me make one tube for him aswell. Just ignore that.. I'm making two tubes, not a sealed box.

How can it be too small ? With endplates it will measure from bottom to top about 69'' and 19.7'' wide.
That's really big.

Can anyone please calculate the air through port and how it will perform in WinISD?

 

[Mike P.]

Can anyone please calculate the air through port and how it will perform in WinISD?

That will depend on the input power and if you are using a Hi-Pass filter or not. Let me know and I'll model it for you.

 

[ironglen]

Sorry, miscommunication. I got you now. If someone doesn't model for you, I'll have to get to it later, sorry. IF you need more volume, consider a slightly larger diameter tube-huge difference in volume with little difference in floorspace requirements...

 

[rodsprit]

Thanks!
I think I'l either use one Behringer EP2500 for both or have one for each driver.. If anyone can recommend what to do that would be great.

Alot of people use a HPF at around 10hz ? I guess I'l do the same.. But can't you calculate if I need it or not in WinISD?

Getting really excited now, payday is in a few days so I can get started ordering stuff

EDIT: Will use the Reckhorn B-2.

 

[fredk]

I was playing with the SDX15 and AV 15H last night and the AV 15H likes a smaller enclosure for similar results. I'm too lazy to upload the graphs right now, but for a 14Hz tune ported enclosure I was at around 290L for the SDX15 and 174L for the AV 15H.

I don't remember if the 15X does better in a smaller or larger box than the H.

These are probably not optimum tunings, but they give you a good idea of the relative volume of box needed.

 

[rodsprit]

Don't remember the exact difference between the H and X. But the X was to be used in ported enclosures, while the H was supposed to be used in closed enclosures.

 

[Mike P.]

I modeled the SDX15 in 252 liters tuned to 15.4 hz with 1000 watts input and a Hi-Pass filter at 15 hz. Port air speed is 26.5 m/s at 14.5 hz. You'll be fine with a 6" diameter flared port.

 

[SteveCallas]

but for a 14Hz tune ported enclosure I was at around 290L for the SDX15 and 174L for the AV 15H

14hz tune in 174 liters means your port is going to suffer. You'd probably have to go with a 4-5" diameter port, which isn't nearly enough for a 15" driver with medium to high displacement. No matter how well the driver models, for a 15" with medium to high displacement, you're going to need to use at least ~250 liters for proper porting.

I modeled the SDX15 in 252 liters tuned to 15.4 hz with 1000 watts input and a Hi-Pass filter at 15 hz

With all due respect Mike, I'm not understanding this recent trend I'm seeing on this forum of designs with a high pass filter centered at or immediately below tune. It doesn't make sense because it is defeating a good chunk of port output and creating a lot of distortion where there should be really low distortion. With a 15hz tune, assuming that one even feels the need to use a highpass filter (which they really shouldn't, especially with two such subs), the highest I would center the frequency of a highpass would be 12hz.

 

[Mike P.]

With all due respect Mike, I'm not understanding this recent trend I'm seeing on this forum of designs with a high pass filter centered at or immediately below tune. It doesn't make sense because it is defeating a good chunk of port output and creating a lot of distortion where there should be really low distortion. With a 15hz tune, assuming that one even feels the need to use a highpass filter (which they really shouldn't, especially with two such subs), the highest I would center the frequency of a highpass would be 12hz.

With a 12 hz high pass what would the air speed be in 252 liters tuned to 15.4 hz with a 6" diameter port?

 

[fredk]

Rod, I see that AE recommends the H for small pr or sealed. Didn't see that the other day.

Steve, I know just enough about Winisd and modeling to be dangerous. Hence the "probably not optimum tunings" disclaimer.

 

[SteveCallas]

With a 12 hz high pass what would the air speed be in 252 liters tuned to 15.4 hz with a 6" diameter port?

At what frequency and how much power?


rodsprit, now that I model this driver, you really should use more than 250 liters with a mid teen tune. The low end rolls off a fair amount with 250 - are you sure you can't go any larger?

 

[rodsprit]

Thanks for the replies!

How much larger are you suggesting?

When I model in WinISD, there is an option ''series resistance'' under signal tab. Should i set this to 2.0 for a 4Ω driver?
WinISD calculates for boxes. I'm using a cylindrical shape, doesn't that change everything it calculates??

Tried modeling some and difference between 250L and 300L wasn't much in SPL with 1000W.

Behringer EP2500 can deliver 2x1200W into 2Ω. If the driver is 4Ω then it can deliver 600W into each driver. Isn't that little when on their specs it says they are supposed to be run by 1000W ?
I could buy two ep2500.. And run bridged.. but 2400W is overkill.

What exactly is a dual 2Ω driver?

 

[Ryan Anderson]

14hz tune in 174 liters means your port is going to suffer. You'd probably have to go with a 4-5" diameter port, which isn't nearly enough for a 15" driver with medium to high displacement. No matter how well the driver models, for a 15" with medium to high displacement, you're going to need to use at least ~250 liters for proper porting.


With all due respect Mike, I'm not understanding this recent trend I'm seeing on this forum of designs with a high pass filter centered at or immediately below tune. It doesn't make sense because it is defeating a good chunk of port output and creating a lot of distortion where there should be really low distortion. With a 15hz tune, assuming that one even feels the need to use a highpass filter (which they really shouldn't, especially with two such subs), the highest I would center the frequency of a highpass would be 12hz.

I've been wondering about this myself... this is at least the second time I've seen using the HPF to decrease airspeed.... tuning to X Hz is where we're supposed to get the most.... which is why airspeed is the most... so why are we trying to cheat and get away with smaller ports to avoid compression and turbulence by effectively turning the volume way down where our efficiency and gain are supposed to be the most?

At what frequency and how much power?


rodsprit, now that I model this driver, you really should use more than 250 liters with a mid teen tune. The low end rolls off a fair amount with 250 - are you sure you can't go any larger?

another thing I'm still trying to understand is unwillingness to give up space. I sure see WAF a lot. No one wants to make an enclosure large enough to maximize capabilities as well as a large enough port diameter. kinda goes hand in hand, doesn't it? Make a little more room for a bigger box which will shorten length so you can bring air speed way down for premium DIY performance. I though that was the whole point to DIY.... not getting a little 15"x15"x15" box with a little 12" so the wiffey doesn't get all upset

 

[Mike P.]

so why are we trying to cheat and get away with smaller ports

Simply because a larger diameter port won't fit.

 

[SteveCallas]

rodsprit, enter your parameters to match my attachment.

Your design ultimately needs to be decided on by you, but if it were me, I'd go with 350 liters and a 7" diameter port that is 34" long for a ~14.6hz tune with no highpass filtering for both subs. A bridged EP2500 for each sub would be ideal, but if cash is tight, a single to run both subs will still work great.

Where do you find a 7" diameter port you may ask? Check a place like Lowes or Home Depot where they sell 6" diameter conceret forms (often referred to by name brand Sonotube), and measure a handful, as they tend to range in size quite a bit. Get the largest one you can find, even if it is only 6.5". Report back what size you can find and we can advise you on the correct length.