First stage--decide on driver....need feedback.

[E-A-G-L-E-S]

That raises a good question. Back in my car audio days, a paper woofer was a big no-no for serious enthusiasts....is it the same nowadays for HT?

 

[darien87]

I built the Rythmik 12" kit and I love it. Check around for my thread with pics. Mine is sealed and does great for me with music and HT. The site also lists plans for ported boxes.

It was my first DIY and came out pretty darn good. I have a very limited amount of tools, but it wasn't that difficult. You can get ther kit, (sub and amp), for about $400, plus about $100 for materials and you're good to go.

 

[E-A-G-L-E-S]

Here is a twist. I remembered my father had some full-range loudspeakers go bad on him which were put in their attic.
The box has a 5" stand and then the enclosure which measures:
20"W
15"D
24"H
So approx. 4.16 cu. ft.
Probably ~4cu. ft. internally.

If possible I would like to use this box and just add internal bracing and 'possibly' a new front panel. I say that because it has a midrange and a horn tweeter in it. So I'm guessing a new front panel is needed for sub only use.
Shame, as it has a 12" in it, albeit a shot one, but the size is right.

IF I go with a whole new panel I suppose I can use a 10", 12" or 15".
Even 2-10's.


What do you guys think? It has a beautiful finish. Can't figure out what type of wood it is though.

 

[avaserfi]

Sonotube is a possiblity as well. I have an old friend who works for a concrete company that can get me 16" or 18" x 12' for really cheap.
Seems like a simple first build and I can go real tall for extra interior volume.
Good option or no in your guys opinion?

A main issue with using a Sonotube is the inability to use a properly designed port such that there will be no port compression at high SPL. If you want to go with a sealed designed a Sonotube could be used, but it is a rounded piece of cardboard so I wouldn't use it...birch ply is way nicer.

They were measured and reportedly are 500w RMS.
If, when, I decide to go bigger I will get a whole new set-up.($90 is hard to pass up)
Two Perfect 12 subs are over my current budget.
Would you be able to lay me out some plans for the amp with one Perfect 12?

I would be willing to provide you with a simplified design for the Kappa VQ, in either a ported or sealed configuration depending on the build you decide on.

Have you seen the Eminence Lab12 Generation II?

I believe it is $132 bucks and looks to model quite well.

I am not aware of any credible third party measurements of this driver, but it is unlikely that the driver maintains linearity and lack of distortion at high SPLs as the VQ does. There is more to a driver than how it models.

That raises a good question. Back in my car audio days, a paper woofer was a big no-no for serious enthusiasts....is it the same nowadays for HT?

At higher frequencies paper is typically not rigid enough to avoid cone break up issues, but in lower frequency applications such as yours this is not an issue.

Here is a twist. I remembered my father had some full-range loudspeakers go bad on him which were put in their attic.
The box has a 5" stand and then the enclosure which measures:
20"W
15"D
24"H
So approx. 4.16 cu. ft.
Probably ~4cu. ft. internally.

If possible I would like to use this box and just add internal bracing and 'possibly' a new front panel. I say that because it has a midrange and a horn tweeter in it. So I'm guessing a new front panel is needed for sub only use.
Shame, as it has a 12" in it, albeit a shot one, but the size is right.

IF I go with a whole new panel I suppose I can use a 10", 12" or 15".
Even 2-10's.


What do you guys think? It has a beautiful finish. Can't figure out what type of wood it is though.

This would likely result in design concessions for the subwoofer, but would be possible. I would not recommend such a route due to small internal volume of the towers. If you do go this route it would be a good idea to buy a driver with large, linear, excursion capabilities and put it in a sealed enclosure with a large amplifier. This would allow for minimal use of the drivers interior space while still achieving respectable low frequency response. Of course, this route would be more expensive due to increased driver and amplifier cost.

 

[E-A-G-L-E-S]

Thanks for the advice.
I thought 4 cu. ft. would be enough for at least a 12" ported if not 15" ported.
If I went sealed I would most likely want a little more power which makes the amp cost more than double in price. Or is 500w RMS to a 12" or 15" in 4 cu. ft. enough juice?

I have been playing with WinISD, but although I grasp a few of the Thiel params., I don't all.
Also I cannot interact with the graphs nor 'really' comprehend them yet.

 

[avaserfi]

Thanks for the advice.
I thought 4 cu. ft. would be enough for at least a 12" ported if not 15" ported.
If I went sealed I would most likely want a little more power which makes the amp cost more than double in price. Or is 500w RMS to a 12" or 15" in 4 cu. ft. enough juice?

I have been playing with WinISD, but although I grasp a few of the Thiel params., I don't all.
Also I cannot interact with the graphs nor 'really' comprehend them yet.

4 cubic feet is enough for the driver, but the slot port itself will take up another half cubic foot to a whole cubic foot in volume depending on how it is configured.

You would most likely want more power than 500 watts in a sealed configuration as every increase of 3dB requires a doubling of power. Thus, to properly equalize the subwoofer it would require about 1000 watts. You could always build a sealed configuration with a lesser amplifier and later buy a higher powered amplifier at which point you could begin to equalize the subwoofer.

 

[E-A-G-L-E-S]

4 cubic feet is enough for the driver, but the slot port itself will take up another half cubic foot to a whole cubic foot in volume depending on how it is configured.

You would most likely want more power than 500 watts in a sealed configuration as every increase of 3dB requires a doubling of power. Thus, to properly equalize the subwoofer it would require about 1000 watts. You could always build a sealed configuration with a lesser amplifier and later buy a higher powered amplifier at which point you could begin to equalize the subwoofer.

Am I understanding you correctly that a 500w amp now could be used without an EQ in it sealed.
Then when I get say a EP2500 or something similar I should get an EQ?
And as far as ported, the remaining 3-3.5 cu. ft isn't in your opinion enough....but is that for a 15" and a 12"?

 

[avaserfi]

Am I understanding you correctly that a 500w amp now could be used without an EQ in it sealed.

Yes, although this will result in initially having a higher F3 and less dynamics overall.

Then when I get say a EP2500 or something similar I should get an EQ?

Yes, ideally you would use a quality high powered amplifier coupled with a equalizer such as the DCX2496. There are less costly alternatives in terms of the equalizer, but they sacrifice functionality for this decreased cost so much so that the price difference is negligible in my opinion.

And as far as ported, the remaining 3-3.5 cu. ft isn't in your opinion enough....but is that for a 15" and a 12"?

If using the 12" Kappa VQ in midQ a 3 cubic foot volume would be sufficient if you could fit a large slot port into the already build cabinets and include proper bracing. The slot port would need to be something along the lines of 3"X12.5"x55" to sufficiently reduce port compression. This size port results in approximately 1.2 cubic feet of volume without any materials being accounted for.

 

[Alex2507]

Yes, ideally you would use a quality high powered amplifier coupled with a equalizer such as the DCX2496.

Unless I miss my guess, setting up a DCX 2496 requires the use of a laptop and measurement equipment. Please understand that I am pretty new to this. About a year ago I bought a Radio Shack SPL Meter and a few months ago I bought the Avia II calibration disk.

I believe WmAx reccomends a LinearX M31 mic for aprox. $175
The DCX 2496 is $275
EP2500 is $330
Laptop (recommendation)? $(?)
mic mixer (recommendation)? $(?)
Anything else? $(?)

I'm just wondering how much it would cost to get in the game.

-Alex

 

[E-A-G-L-E-S]

Yes, although this will result in initially having a higher F3 and less dynamics overall.



Yes, ideally you would use a quality high powered amplifier coupled with a equalizer such as the DCX2496. There are less costly alternatives in terms of the equalizer, but they sacrifice functionality for this decreased cost so much so that the price difference is negligible in my opinion.



If using the 12" Kappa VQ in midQ a 3 cubic foot volume would be sufficient if you could fit a large slot port into the already build cabinets and include proper bracing. The slot port would need to be something along the lines of 3"X12.5"x55" to sufficiently reduce port compression. This size port results in approximately 1.2 cubic feet of volume without any materials being accounted for.

Once again, sorry...there are terms I still do not know.
I understand F3, but what do you mean by 'less dynamics'?

What does the DCX2496 do that say a eQ.2 doesn't that is important? Would you say I'd need the DCX for sealed and/or ported ?

Obviously I don't have the internal space for a 55" anything.
I thought for sure I could use a 4cu.ft. box, oh well.
At least this leaves my driver and amp options open....though this gets tougher as I learn more.

 

[E-A-G-L-E-S]

Unless I miss my guess, setting up a DCX 2496 requires the use of a laptop and measurement equipment. Please understand that I am pretty new to this. About a year ago I bought a Radio Shack SPL Meter and a few months ago I bought the Avia II calibration disk.

I believe WmAx reccomends a LinearX M31 mic for aprox. $175
The DCX 2496 is $275
EP2500 is $330
Laptop (recommendation)? $(?)
mic mixer (recommendation)? $(?)
Anything else? $(?)

I'm just wondering how much it would cost to get in the game.

-Alex

Boy I hope you are wrong, at least to some degree.
Mic mixer?
Nearly $300 for EQ.
I'm almost at my budget just there with building materials included. :sad:

I'm hoping those are things meant to tweak your set-up, but not needed to run it.

 

[avaserfi]

Unless I miss my guess, setting up a DCX 2496 requires the use of a laptop and measurement equipment. Please understand that I am pretty new to this. About a year ago I bought a Radio Shack SPL Meter and a few months ago I bought the Avia II calibration disk.

I believe WmAx reccomends a LinearX M31 mic for aprox. $175
The DCX 2496 is $275
EP2500 is $330
Laptop (recommendation)? $(?)
mic mixer (recommendation)? $(?)
Anything else? $(?)

I'm just wondering how much it would cost to get in the game.

-Alex

Need of these materials is dependent on a few things. For example, if you will only be needing an equalizer another option is the Behringer feedback destroyer. This unit is only about $100 and not as full featured as the DCX2496. Also, if you are only equalizing the low end it is actually possible to use a radio shack SPL meter with correction values available at various sources online such as the hometheatershack who also has free measurement software called room eq wizard.

As far as recommendations go:

Behringer ECM8000 microphone - $50 - Calibrating the microphone would be ideal and costs about $40 more from the right sources, but isn't necessarily as fairly accurate correction values are available for the low end.

Behringer ub802 Mixer - $50 - this is also a superb headphone amplifier

Laptop - something with a decent sound card or just get an external sound card. Nothing fancy needed, something with XP and enough power to run Room EQ Wizard. If you can run wires from your desktop computer to your receiver then there is no actual need for a laptop.

Do note that this is the ideal situation. As pointed out there are some less expensive alternatives.

Boy I hope you are wrong, at least to some degree.
Mic mixer?
Nearly $300 for EQ.
I'm almost at my budget just there with building materials included. :sad:

I'm hoping those are things meant to tweak your set-up, but not needed to run it.

The only thing listed needed to run the system is the amplifier. Everything else is required for achieving optimal sound quality.

 

[E-A-G-L-E-S]

So these are things that are not only able to be added later, but possibly that is the best thing for me anyway as it will allow me to see what I like and don't like about my initial design. Plus it gives me a little more time to learn and to save for those extras.
Make sense?

 

[E-A-G-L-E-S]

I realized that I cannot use a larger amp, as I would go way over my power load and I cannot add another 15A service.
So ~500/600 is as high as I can go.(had the LT550 with no power issues that I noticed)

I believe this is know what I have to base all my other choices off of.
So with a 'power limit' and no space limitations, what should be my first purchase after a ~500/600w amp? Driver or enclosure type?

 

[avaserfi]

I realized that I cannot use a larger amp, as I would go way over my power load and I cannot add another 15A service.
So ~500/600 is as high as I can go.(had the LT550 with no power issues that I noticed)

I believe this is know what I have to base all my other choices off of.
So with a 'power limit' and no space limitations, what should be my first purchase after a ~500/600w amp? Driver or enclosure type?

A 4 cubic foot enclosure with a slot port that measures 3" x 12.5" x 55" would be recommended with the VQ in midQ mode.

Here are images of such an enclosure modeled with 400 watts:

Transfer function:

SPL at 400 watts:

Cone excursion:

Port air velocity:

Impedance does not drop below 4 ohms in the passband. You will notice a slight jump over rated xmax in in the excursion graph. Due to the Kappas conservative xmax rating this is not an issue with regard to sound quality or damaging the driver.

Ideally this design would have a 4th order crossover placed no higher than 80Hz and a high pass protection filter at 20Hz to ensure during extremely high SPL situations the driver is not forced to over extend itself.

 

[E-A-G-L-E-S]

Wow...thanks Andrew!!!
110dB @ ~23Hz....not bad.

4th order x-over....will the one in my Yamaha RV-661 work?

High Pass filter....there are amps with this built in, no?
The O-audio amp is 450wRMS, I wonder if that has a high pass.

3"x12.5"x55"....loooong, thin box. How much room at the end of the 55" would I need to the rear of the box?(I plan on front firing port and driver)
Also, how tough for a first timer with limited skills is a large slot port?

...I see this is your set-up as well. You must like it if you are reccomending it.

 

[avaserfi]

Wow...thanks Andrew!!!
110dB @ ~23Hz....not bad.

This is modeled. In room performance will likely exceed these numbers due to room gain. I have measured 120dB+ at 20Hz with the sub corner loaded.

4th order x-over....will the one in my Yamaha RV-661 work?

This will work, but will not allow for ideal integration.

High Pass filter....there are amps with this built in, no?

Yes, some amps are capable of doing this. Although, eventually you will want a DCX2496 or something of similar capabilities which will allow for more precise control.

3"x12.5"x55"....loooong, thin box. How much room at the end of the 55" would I need to the rear of the box?(I plan on front firing port and driver)
Also, how tough for a first timer with limited skills is a large slot port?

There are various ways to build a slot port. I have been asked to design a simple version of the recommended cabinet and will work on it and hopefully have it ready in a few days. This will likely be a cabinet that has a forward firing subwoofer with a forward facing slot port. Building a slot port is more complicated than using a typical round port, but the VQ build you see was my first build as well...So it isn't impossible.

...I see this is your set-up as well. You must like it if you are reccomending it.

Simply put the subwoofer is superb.

 

[E-A-G-L-E-S]

Excellent...I look forward to it.
Does that O-audio seem to be the perfect fit? Or how about the VT3's for $90 at a reported 500wRMS?

 

[avaserfi]

Excellent...I look forward to it.
Does that O-audio seem to be the perfect fit? Or how about the VT3's for $90 at a reported 500wRMS?

I am not aware of the actual performance of these amps, but if they really do put out 500 watts then they will be sufficient. My typical recommendation is a Behringer EP2500 for this application due to its superb build quality, relatively low price and transparency as well as its ability to push two subwoofers. Sadly, this amplifier seems to be out of your budget.

 

[E-A-G-L-E-S]

For this build. Bash 500 and LT550 as well, but then I'm close to EP2500 price territory.
This is a starter, but don't want a complete lack of performance.
I could even use a cheaper, not as good driver if I can get decent results.
This is for learning and enjoyment.
When I get this under my belt I will try a second being the opposite of this, so sealed now ported next or vice-a-versa.

Within a year or so I will go dual 15" with a nice pro amp and performance only driven.