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Discussion Starter · #1 ·
I have been throwing around the idea of a DIY sub. I chose a fairly midrange sub and amp combo and a really nice guy at parts express helped me design the box. All nearly 10 cu ft of it! :gulp: Is this because of my particular speaker choice. If it helps any, it is a Dayton RSS390HF-4. I would like to do ported because of its advantages but when reality sets in, that is just plain too big. I have a ported klipsh 12 that is tiny in comparison. So if I chose a better speaker, can I go considerably smaller with the same performance?
 

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You don't necessarily need a "better" driver, just one with different TS parameters. How the driver is designed, with regards to its specifications, dictates what alignment it works best in, the size of enclosure required, amp power needed, etc. Perhaps if you told the PE rep what you're looking to achieve he might be able to suggest something different.

Another option would be a pre-designed kit, and PE sells those as well. DIY Sound Group has a bunch too, in both sealed and ported models.
 

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Wait are you saying this is a sealed cabinet of 10cuft?

WOW if it is. Here are PE's examples:
Sealed Volume 2.88 ft.³ Sealed F3 37 Hz

Vented Volume 8.96 ft.³ Vented F3 21 Hz

SO not sure why you went so large.
 

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Discussion Starter · #5 · (Edited)
You don't necessarily need a "better" driver, just one with different TS parameters. How the driver is designed, with regards to its specifications, dictates what alignment it works best in, the size of enclosure required, amp power needed, etc. Perhaps if you told the PE rep what you're looking to achieve he might be able to suggest something different.

Another option would be a pre-designed kit, and PE sells those as well. DIY Sound Group has a bunch too, in both sealed and ported models.
Thank you...will this work for the hf as well (it specifies the ho model) > http://www.diysoundgroup.com/cube15.html

This is much better size-wise and will be much easier to talk the wife into.

edit: looks like 4 cu ft with that sub will be -7db at 20hz :(
 

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Why is -7db at 20hz bad?

Thats before EQ.
 

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Yes F7 is fine for a sealed sub. My pair of 18's I have in sealed cabinets are about 45hz -7db. With EQ they sound awesome. Not ULF monsters but everything I wanted in a small sealed cabinet.
 

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In 4cuft what are you trying to tune the port to?

When using this driver it does like large volumes when porting. As Jman stated you just need a driver that likes small volumes. BUT when trying to port in a small cabinet with a 15" you will end up taking a LOT of room with the port size needed. So to keep air speed down in the port you will need a port size thats pretty big and because of the small volume used it will need to be a long port also. SO its a balancing act of how low you can tune.

Here is a design that would work for you. It has about a 18hz -7db point. It works with the 15 also.




The above image has the Dayton 390HO 15" 23hz tune 1100watts and it is the green line. As I just noticed you have the HF driver not HO. So this will not work. I figured I would leave this idea for you thought because maybe you can buy the Ho driver. If not just used the HF sealed.
 

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Discussion Starter · #11 ·
This is why my original question was 'if I choose a better driver can I accomplish.....' I talked to the PE rep and I don't think I am going to accomplish what I want to do with a ported driver (size restraints that I have). He suggested a Dayton Ultimax 15 in a sealed enclosure and doubling my amplifier (from 500w to 1000w). I know this will roll off sooner than ported but will the EQ be able to overcome this and get me bass response down to ~18 hz? For not alot more, I am considering just buying the Klipsch R-115SW which is ported. How would the ultimax and dayton sa1000 in a diy 3cu ft sealed box stack up against the ported klipsch for bass response below 20hz?
 

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Getting bass response down to "X," frequency can be done with almost any driver. Its more of a question of how SPL does it produce. Chances are the Klipsch is ported up close to the design I posted earlier. SO it should do fine down to about 18/19hz then fall off a cliff. The UM15 in a sealed alignment will probably be better at midbass and below 15hz. Depends on a few variables, mainly the room. Ported verse sealed sound different to me. And ported verse sealed the ported will win near the port tuning by quite a bit.

I would use your sub in a sealed cabinet and see how you like it. If its not enough but the appropriate driver for a ported enclosure tuned to around 22hz. This will keep the external size down. BUT when trying to port closer to 17hz you need more room such as 6cuft.

EQ can help the roll off fall at a much slower rate. And in room gain and it falls even slower. At low volumes you may not be able to tell the difference in ULF. When near its max potential you will definitely tell the difference near 20hz. The Klipsch is good to about 18hz and not usable at 16hz. Thats where the UM15 would easily outperform.
 

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What amp are you planning on using?

I have the RSS390HF with a Bash 300W amp in an 8cft ported box tuned to 15hz. If I tried the use the Bash 500W I would have exceed Xmax almost completely across the range...

Attached are the sketchup model, WinISD file and pictures showing the design and actual build
 

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Nice bracing!
 
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