Mystery Subwoofer - How best to not screw up a DIY build?

  • Thread starter audioholics2121
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A

audioholics2121

Audiophyte
Hello all. I apologize for the background info but it paints a picture. Thank you for any advice and help!
Background
I purchased a 12" subwoofer off a site called DIYCable that is no longer around. I bought it many years ago and I honestly can't remember what model it was. The box it self says "Exodus Shiva-X" with a part number XJ-12.

When I google "Exodus Shiva XJ-12" the best I can come up with is that this sub was a limited run of a 12" sub that the build house got wrong, changing the intended use/specs slightly. The company, Exodus Audio, sold these off at a discount rather than sending them back to the build house.

My issue is...I'm only assuming this is the sub in the box because that is what the box it was shipped in said.

Questions:
1. So I'm reading that 3.5cu ft box is what I should build. Am I right that this would be 18.22" * 18.22" * 18.22"? Should it be ported or sealed?
2. I see parts express has a 250 plate amplifier that has DSP which would be cool. As far as amplification goes, would 250 watts be enough?
3. Is there anything I'm missing besides the box and the plate amplifier?





Message I found when googling:

"There are also XJ-12 12" models available!
They have a highish Q of about .9 (system Q, not driver Qts) but in the car that would give you a lot of thump, essentially flat anechoic to 40Hz and with cabin gain that would be insane. Same motor, slightly different parameters. They also look good in 3.5ft^3 tuned to about 20Hz. They would be a good HT sub in that type of enclosure being essentially flat to 30Hz (anechoic) and fall off fairly quick below that point. In-room measurements as a typical company would post they would be good to under 20Hz flat in-room with some good HT excitement in the 30-60hz range.
Parameters on the XJ-12 with VCs in parallel (dual 8s).
Re: 3.95
fs: 31Hz
Qms: 4.35
Qes: .67
Qts: .58
mms: 114g
cms: .233 mm/N
Vas: 83L
BL: 11.4
Eff: 87.7db/1W/1M
xmax: 26-27mm one way
Pmax: Lets say 600W which is conservative. If you thermally fry the thing your doing something very stupid."
 

Attachments

TLS Guy

TLS Guy

Audioholic Slumlord
Hello all. I apologize for the background info but it paints a picture. Thank you for any advice and help!
Background
I purchased a 12" subwoofer off a site called DIYCable that is no longer around. I bought it many years ago and I honestly can't remember what model it was. The box it self says "Exodus Shiva-X" with a part number XJ-12.

When I google "Exodus Shiva XJ-12" the best I can come up with is that this sub was a limited run of a 12" sub that the build house got wrong, changing the intended use/specs slightly. The company, Exodus Audio, sold these off at a discount rather than sending them back to the build house.

My issue is...I'm only assuming this is the sub in the box because that is what the box it was shipped in said.

Questions:
1. So I'm reading that 3.5cu ft box is what I should build. Am I right that this would be 18.22" * 18.22" * 18.22"? Should it be ported or sealed?
2. I see parts express has a 250 plate amplifier that has DSP which would be cool. As far as amplification goes, would 250 watts be enough?
3. Is there anything I'm missing besides the box and the plate amplifier?





Message I found when googling:

"There are also XJ-12 12" models available!
They have a highish Q of about .9 (system Q, not driver Qts) but in the car that would give you a lot of thump, essentially flat anechoic to 40Hz and with cabin gain that would be insane. Same motor, slightly different parameters. They also look good in 3.5ft^3 tuned to about 20Hz. They would be a good HT sub in that type of enclosure being essentially flat to 30Hz (anechoic) and fall off fairly quick below that point. In-room measurements as a typical company would post they would be good to under 20Hz flat in-room with some good HT excitement in the 30-60hz range.
Parameters on the XJ-12 with VCs in parallel (dual 8s).
Re: 3.95
fs: 31Hz
Qms: 4.35
Qes: .67
Qts: .58
mms: 114g
cms: .233 mm/N
Vas: 83L
BL: 11.4
Eff: 87.7db/1W/1M
xmax: 26-27mm one way
Pmax: Lets say 600W which is conservative. If you thermally fry the thing your doing something very stupid."
That does no look like a good sub driver. I can model it if you want. However its free air resonance is high for a sub driver at 31 Hz. You really can not make a driver work well below Fs. Even then with a Qts at 0.58 it looks at first glance that it needs a sealed alignment. That will push F3 pretty high, and require gobs of power and lots of Eq below F3.

That driver will be a challenge, and with drivers available now, I doubt that driver would be worth the trouble or expense, but without formally modelling it, I can't tell you that for sure.
 
A

audioholics2121

Audiophyte
If you don't mind modelling it I'd appreciate the feedback : )

I guess I'm in a spot where I've already got the driver and want a subwoofer to pair with some Klipsch Heresy I that I found at Goodwill that don't go very low.

I do hear what you are saying though - that the driver is limited in what application it will work in. I even found another post where the person was saying the the build house mistake made the driver lend itself to infinite baffle/open baffle (not sure what this means).
 
TLS Guy

TLS Guy

Audioholic Slumlord
If you don't mind modelling it I'd appreciate the feedback : )

I guess I'm in a spot where I've already got the driver and want a subwoofer to pair with some Klipsch Heresy I that I found at Goodwill that don't go very low.

I do hear what you are saying though - that the driver is limited in what application it will work in. I even found another post where the person was saying the the build house mistake made the driver lend itself to infinite baffle/open baffle (not sure what this means).
I will see if I can get time to model it this week. However there is a good chance you will still save money with another driver, due to the expense of the amp power required and Eq.
 
Kingnoob

Kingnoob

Audioholic General
Hello all. I apologize for the background info but it paints a picture. Thank you for any advice and help!
Background
I purchased a 12" subwoofer off a site called DIYCable that is no longer around. I bought it many years ago and I honestly can't remember what model it was. The box it self says "Exodus Shiva-X" with a part number XJ-12.

When I google "Exodus Shiva XJ-12" the best I can come up with is that this sub was a limited run of a 12" sub that the build house got wrong, changing the intended use/specs slightly. The company, Exodus Audio, sold these off at a discount rather than sending them back to the build house.

My issue is...I'm only assuming this is the sub in the box because that is what the box it was shipped in said.

Questions:
1. So I'm reading that 3.5cu ft box is what I should build. Am I right that this would be 18.22" * 18.22" * 18.22"? Should it be ported or sealed?
2. I see parts express has a 250 plate amplifier that has DSP which would be cool. As far as amplification goes, would 250 watts be enough?
3. Is there anything I'm missing besides the box and the plate amplifier?





Message I found when googling:

"There are also XJ-12 12" models available!
They have a highish Q of about .9 (system Q, not driver Qts) but in the car that would give you a lot of thump, essentially flat anechoic to 40Hz and with cabin gain that would be insane. Same motor, slightly different parameters. They also look good in 3.5ft^3 tuned to about 20Hz. They would be a good HT sub in that type of enclosure being essentially flat to 30Hz (anechoic) and fall off fairly quick below that point. In-room measurements as a typical company would post they would be good to under 20Hz flat in-room with some good HT excitement in the 30-60hz range.
Parameters on the XJ-12 with VCs in parallel (dual 8s).
Re: 3.95
fs: 31Hz
Qms: 4.35
Qes: .67
Qts: .58
mms: 114g
cms: .233 mm/N
Vas: 83L
BL: 11.4
Eff: 87.7db/1W/1M
xmax: 26-27mm one way
Pmax: Lets say 600W which is conservative. If you thermally fry the thing your doing something very stupid."
Robust driver , your going to need a powerful amplifier and a sealed sub probably best . Looks like Dayton titanic sadly also discontinued I wanted one Zzz never got one .
What’s the Rms ?

I have this sub but I don’t use it often
Found video of the model , not my video!!

Sent from my iPhone using Tapatalk
 
Last edited:
A

audioholics2121

Audiophyte
@Kingnoob I could not find RMS listed anywhere. The site that sold the driver is no longer up : /
 
Kingnoob

Kingnoob

Audioholic General
@Kingnoob I could not find RMS listed anywhere. The site that sold the driver is no longer up : /
Guess you have to look up model online more , or try a amp at least 500 watts rms . I don’t understand how so many nice subs died out , maelstrom 18 is gone I wanted one .::: rip

My mom hates bass so no reason to buy another big sub .
Sent from my iPhone using Tapatalk
 
Last edited:
A

audioholics2121

Audiophyte
Yeah it's hard to find much info on this model. I tried to use the way back machine but can't pin down the exact page.

The Pmax was given as 600watts conservatively
 
Kingnoob

Kingnoob

Audioholic General
Yeah it's hard to find much info on this model. I tried to use the way back machine but can't pin down the exact page.

The Pmax was given as 600watts conservatively
Ahh it’s probably similar wattage to this one
My sub is 600w rms but I run a 500 w amp so I lose a little power .
This 12 is like my 15 diy but mines sealed.

It has twice my subs xmech lol
My subs thread diy https://www.diyaudio.com/forums/subwoofers/231648-si-sub-help.html
Sent from my iPhone using Tapatalk
 
TheWarrior

TheWarrior

Audioholic Ninja
The fs or resonance frequency is a bit high for a subwoofer. Low A on a piano is 27.5 hz and that driver will struggle to reproduce content below 30 hz. Plus, it seems that if there was a manufacturing defect, you're really HOPING the posted T/S specs are even accurate.

This is probably not worth the effort to build an enclosure unless you've really got the time to tinker and the ability to measure T/S parameters. Guessing does not get you far with loudspeakers. Either way, good luck!!!!
 
A

audioholics2121

Audiophyte
I hear that. Those specs were what was listed by the owner for the 'mistake' batch when he was selling those off. The way he presented it in the forum post I read, those are the actual specs of the driver delivered to him and were not the specs his prototype was aiming at he and the build house agreed to a lower price per unit instead of shipping them back. So he sold them at a discount.

Here is the post I found which is the best I can come up with regarding this driver. There was apparently a 15" and 12"


 
TLS Guy

TLS Guy

Audioholic Slumlord
Thank you so much for the help!
So here is your model. As I warned you this driver is less than ideal. It is only suitable for sealed alignment. It is not suitable for any other alignment.

As I warned you, without bass Eq the F3 is high and is 46.4 Hz. It has an acceptable Q of .71 in a 2 cu.ft sealed box. I would allow about 0.1 of a cu.ft for the driver air displacement and you will also have to add the volume of bracing. As I explained before you can not drive a speaker much below Fs. The model shows you can not increase output below 25 Hz no matter how much power you give it. Now the -3db point without Eq is 46.4 Hz. So you need to start a bass boost of 12 db per octave starting at 50 Hz. Now you need to understand what this means. For the same spl a 60 watt drive will give you at 50 Hz you will need the full 600 watt drive at 25 Hz, actually a little more.
You will also need to have a 12 db per octave high pass filter at 25 Hz and cut the sub off there.

You will need to fill the enclosure completely with Polyfill without compressing it.

So this has turned out exactly as my rough off the cuff calculations in my head predicted, before doing the model. I did have to make an educated guess as to the actual cone diameter. I bet I'm close and certainly close enough not to affect the results.

So you will need a plate amp that will give the full 600 watts, and you will need it to have DSP or other means of Eq, to boost 12 db per octave below 50 Hz and provide at least 12 db per octave attenuation below 25 Hz.

I leave it to you to decide whether this is worth the effort and expense. That is your cost benefit/effort equation. Just because you have this driver, only you can decide if you should use it for your build.
 

Attachments

Last edited:
A

audioholics2121

Audiophyte
Thank you so much!

So in the end, I could get better performance for less money just starting from scratch (selling this driver I mean)?
 
TLS Guy

TLS Guy

Audioholic Slumlord
Thank you so much!

So in the end, I could get better performance for less money just starting from scratch (selling this driver I mean)?
As I said, that is up to you to decide. I don't know what sort of performance you desire, what your space requirements are, your budget, and especially how comfortable you are at being able to implement the design. We go through this a lot, in that people think a sealed design is an easier build, as it just a strong box. So, yes the carpentry is easier, but the design and successful implementation are significantly harder. Apart from that, is that the only pressing incentive for this design would be if your space is very limited. That really is actually the only good reason to go with a sealed design for a low frequency reproducer. After that it is actually all negative. The reason is simple. A loudspeaker cone by itself is a very poor coupler to the air in the room at low frequencies. So an efficient acoustic transformer/coupler improves the situation enormously. That means Helmholtz resonators, pipes, or horns. The commonest being the former.
 
A

audioholics2121

Audiophyte
Yes sorry I should have given more details and again thank you for running the specs through the software and providing an interpretation for me.

I've got a pair of Klipsch Heresy I and a pair of AR 2ax speakers. I run them off a Yamaha CR-840 amplifier. What I've noticed is I actually like the way it sounds with both pairs of speakers running (A and B channel on). It feels like the AR fill in where the Heresy lack in bass, however it does sort of sound like vocals are coming from two places...if that makes sense.


When I remembered I had this driver at my parents house I thought I'd put it to use. Mainly for music but also for some HT use.

My budget would ideally be 300 or so for the build, including an amp. This may mean that buying off the shelf is better but I do like to do stuff like this so maybe DIY is part of the fun : )

The room my stereo/TV are in is about 17'x17'. I don't listen to much in the way of bass heavy music but the Heresy by themselves are pretty bright and lacking in bass and the AR by themselves are just a tad too laid back (tweeters probably shot after 50 years).

Anyways I realize I've got to do some digging here but you've been very knowledgeable and helpful. I'll have to see what can be done for $300 or there abouts and consider selling this driver if that ends up being the best bet.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Yes sorry I should have given more details and again thank you for running the specs through the software and providing an interpretation for me.

I've got a pair of Klipsch Heresy I and a pair of AR 2ax speakers. I run them off a Yamaha CR-840 amplifier. What I've noticed is I actually like the way it sounds with both pairs of speakers running (A and B channel on). It feels like the AR fill in where the Heresy lack in bass, however it does sort of sound like vocals are coming from two places...if that makes sense.


When I remembered I had this driver at my parents house I thought I'd put it to use. Mainly for music but also for some HT use.

My budget would ideally be 300 or so for the build, including an amp. This may mean that buying off the shelf is better but I do like to do stuff like this so maybe DIY is part of the fun : )

The room my stereo/TV are in is about 17'x17'. I don't listen to much in the way of bass heavy music but the Heresy by themselves are pretty bright and lacking in bass and the AR by themselves are just a tad too laid back (tweeters probably shot after 50 years).

Anyways I realize I've got to do some digging here but you've been very knowledgeable and helpful. I'll have to see what can be done for $300 or there abouts and consider selling this driver if that ends up being the best bet.
Well, you have a driver to sell. I think we can come out on budget. The trick to coming out on budget, is to work with the laws of physics, and not fight them.

I have a design ready to go. I have it in use and I could not be more pleased with it. It is an absolute keeper.

This is the driver you would need, which takes about half your budget.

It is a transmission line sub, which is very efficient and 100 to 250 watts will power it just fine in a large space.

Here are the pictures.





It was designed as an in wall sub, but does not have to be.



This is the plan. It is 10" deep.



This is the FR.



This is the model.

The unit is powered by a 250 watt amp and it fills a very large space evenly and with ease. TLs have a phenomenally good bass quality.

The boards can be cut at A & K cabinets at Albany MN, where the boards are still in the C & C computer. I'm sure I could find the price and arrange to ship if you don't want to cut the boards yourself.

This is the system it was designed for.
 
A

audioholics2121

Audiophyte
That is so cool! I'm going to have to do some measuring. Is that 25.5" x 86" x 10"(deep)?
 
Kingnoob

Kingnoob

Audioholic General
Well, you have a driver to sell. I think we can come out on budget. The trick to coming out on budget, is to work with the laws of physics, and not fight them.

I have a design ready to go. I have it in use and I could not be more pleased with it. It is an absolute keeper.

This is the driver you would need, which takes about half your budget.

It is a transmission line sub, which is very efficient and 100 to 250 watts will power it just fine in a large space.

Here are the pictures.





It was designed as an in wall sub, but does not have to be.



This is the plan. It is 10" deep.



This is the FR.



This is the model.

The unit is powered by a 250 watt amp and it fills a very large space evenly and with ease. TLs have a phenomenally good bass quality.

The boards can be cut at A & K cabinets at Albany MN, where the boards are still in the C & C computer. I'm sure I could find the price and arrange to ship if you don't want to cut the boards yourself.

This is the system it was designed for.
Wow wish I had the skills to build that ,
Why do no brands sell cheap t lines ? I’ve seen zero of any price ...
Does it have similar output to a double ported sub ?
I don’t have the space for anything that large .
Good luck !!!
Sent from my iPhone using Tapatalk
 

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