DIY Modified dual 10" Dayton DVC sealed to 12" Dayton HF

[Guiria]

My bro-in-law has a box with 2 10" Dayton DVC subs (SD270-88 23 bucks each). The box is 3.2^3 ft, both drivers are mounted on the front baffle. The space inside the box is not seperated for each driver, just one big cavity. The sub is powered by the PE SA240 240 watt plate amp.

He can pick up a Dayton RSS315HF 12" sub for about 100 bucks and is thinking about making his 3.2^3 ft. box into a ported box for the 12" sub by adding a new front baffle. The port would be 4" x 24" long and he would use two of them. There would have to be an elbow in each port.

Running some numbers in WinISD Pro the box seems to be ok. The slightly smaller than ideal size makes the roll off pretty gradual starting at about 40 hz and ending up with the -3 db at 21 hz.

All this rambling brings me to my question. Does anyone have another recommendation for a $100 driver that would perform better given the box size and amplifier restraints? This will be a very budget limited project. One more thing to add is that the baffle is not wide enough to accomodate a 15" driver, 12" is the max.

Another question is that I've never really used WinISD Pro and I wouldn't mind someone confirming my results.

Thank you in advance.

 

[TLS Guy]

My bro-in-law has a box with 2 10" Dayton DVC subs (SD270-88 23 bucks each). The box is 3.2^3 ft, both drivers are mounted on the front baffle. The space inside the box is not seperated for each driver, just one big cavity. The sub is powered by the PE SA240 240 watt plate amp.

He can pick up a Dayton RSS315HF 12" sub for about 100 bucks and is thinking about making his 3.2^3 ft. box into a ported box for the 12" sub by adding a new front baffle. The port would be 4" x 24" long and he would use two of them. There would have to be an elbow in each port.

Running some numbers in WinISD Pro the box seems to be ok. The slightly smaller than ideal size makes the roll off pretty gradual starting at about 40 hz and ending up with the -3 db at 21 hz.

All this rambling brings me to my question. Does anyone have another recommendation for a $100 driver that would perform better given the box size and amplifier restraints? This will be a very budget limited project. One more thing to add is that the baffle is not wide enough to accomodate a 15" driver, 12" is the max.

Another question is that I've never really used WinISD Pro and I wouldn't mind someone confirming my results.

Thank you in advance.

Just seen your post. I will run your numbers later. I'm busy writing up my time at SOTU with my impressions of the sound on offer.

 

[TLS Guy]

Just seen your post. I will run your numbers later. I'm busy writing up my time at SOTU with my impressions of the sound on offer.

I have modeled that driver before, for somebody else. The Qts is 0.56. That driver is only suitable for sealed alignment. You box is optimal size for two of those drivers in a sealed enclosure. F3 will be 42 Hz, but you can add 12 db per octave EQ starting at around 50 Hz.

Sorry, that 12 inch driver is for sealed enclosures only.

 

[Guiria]

Hmmm...scratch head...

I'm not sure his budget would allow two of them. Educate me if you will on why a Qts of .56 leads itself to only being used in a sealed alignment. I know the EBP is 44.2 and calculated by fs/Qes. To me that also indicates that it should be used in a sealed alignment but I've seen people use such drivers, with low EBP, in ported enclosures. I guess I've never listened to one though.

Thanks,

 

[TLS Guy]

Hmmm...scratch head...

I'm not sure his budget would allow two of them. Educate me if you will on why a Qts of .56 leads itself to only being used in a sealed alignment. I know the EBP is 44.2 and calculated by fs/Qes. To me that also indicates that it should be used in a sealed alignment but I've seen people use such drivers, with low EBP, in ported enclosures. I guess I've never listened to one though.

Thanks,

The problem, is that QL gets too high. so you have a boomy over resonant enclosure. I modeled it, and you get a 7 db ripple peak at 50 Hz. That sub would be a boomer, and the Fs is still quite high at 32. 5 Hz. The roll off will be 24 db per octave, and the sealed 12db per octave. So all you will have is a boomer, instead of a nice tight bass. The low bass output will be a wash.

They both have the same output at 28 Hz, at 20 Hz the sealed enclosure has 6db more output then the vented you were planning.

I would use half the box, and get another driver as funds permit, or build a 1.6 cu. ft box.

 

[TLS Guy]

Take a look at this Torrent driver

I have had a look through what I have modeled. This Torrent driver looks to be your best bet, and I have it already to go on my website! May be you could build the slot vent external to the enclosure?

 

[Guiria]

He ended up replacing one of the drivers with the matching Dayton passive radiator. From my calculations, with the passive weighted to 100 grams (stock weight) the F3 of the system is 25 Hz.

It plays a little boomy and I'm not sure if that's room placement or not, I'm not sure how many options he has for moving the sub but it is definitely lower than his sealed configuration. I don't think it is as tight sounding as before.

Question of the day is we want to put in a sub sonic filter to protect the driver from bottoming, which it has already. What frequency do you go for with the above mentioned system and how steep of a roll off do you use to protect the driver??? He has the Dayton SA240 plate amp without boost.

I'm off to research sub sonic filters.