Newbie DIY sub advice

[lsiberian]

Seems like Rojo has done a lot of work for you and those eminence drivers look promising. I would caution against the Kicker driver because do they tend to be oriented to SPL more than sound quality. Of course properly tuned it would still destroy most commercial subs.

If you are going to hire out the project. You might get the Infinity Kappa 120.9w and use the below thread which has all the heavy lifting done for you.

http://forums.audioholics.com/forums/threads/simple-12-infinity-kappa-vq-midq-plans.45528/

Even if you don't use the exact build it shows you how to properly fold a slot port and build a ported box.

I will say everyone seem to pushing ported, but I hope you at least give yourself a chance to hear both and determine your preferences. I myself tend to prefer sealed systems. One of the reasons we have so many options for speakers is that we all have different preferences.

 

[lovinthehd]

Behringer are there
https://www.amazon.co.jp/s/ref=nb_sb_noss_2?__mk_ja_JP=カタカナ&url=search-alias=aps&field-keywords=inuke
and there are (rebranded?) Amcron amps which is both named and looked exactly as Crown
https://www.amazon.co.jp/s/ref=nb_sb_noss?__mk_ja_JP=カタカナ&url=search-alias=aps&field-keywords=xls+drivecore&rh=i:aps,k:xls+drivecore
They are more expensive it seems than behringers.

FWIW in the Crown XLS manuals I have they indicate some models may be exported under the name Amcron and also has a claim for trademark under the Crown, Crown Audio and Amcron names for Crown International.....

 

[lovinthehd]

Seems like Rojo has done a lot of work for you and those eminence drivers look promising. I would caution against the Kicker driver because do they tend to be oriented to SPL more than sound quality. Of course properly tuned it would still destroy most commercial subs.

If you are going to hire out the project. You might get the Infinity Kappa 120.9w and use the below thread which has all the heavy lifting done for you.

http://forums.audioholics.com/forums/threads/simple-12-infinity-kappa-vq-midq-plans.45528/

Even if you don't use the exact build it shows you how to properly fold a slot port and build a ported box.

I will say everyone seem to pushing ported, but I hope you at least give yourself a chance to hear both and determine your preferences. I myself tend to prefer sealed systems. One of the reasons we have so many options for speakers is that we all have different preferences.

Curious how you determine SQ vs SPL for a given driver? Aren't they a combined function with the amount of distortion resulting? I like sealed subs for size and ease of construction, but takes several of them to get somewhere....

 

[BoredSysAdmin]

Kicker C154+iNuke 1000 = about $450. Leaves plenty of room in budget for box construction.
Only one glaring possible issues (as mentioned) would be box size. 2'x2'x2' is not exactly small
On the positive side - nothing, NOTHING available commercially would be able to touch it as far as performance goes.

Lsiberian might have a point about Kicker is not known to build low-distortion (aka musical) drivers. What makes it even worse is comp stands for Competition series, as it competition for LOUDEST audio levels and yes - they do exists.

- 152dBs inside the car.... - 120db will damage permanently your hearing and it's logarithmic scale....

In addition - PE suggested box sizes here:
http://www.parts-express.com/kicker-c154-comp-series-15-subwoofer-4-ohm--267-6911
they say it could work in small sealed box of only 2.5cuft but at expense of extension - f3 of 46hz.
if you go with iNuke1000(2000?) DSP model - you could improve it a bit with EQ.
EQ up does require more power from amp.

 

[lovinthehd]

I'm just saying just judging a driver (or any audio device) by brand name alone could be an error....

 

[BoredSysAdmin]

I'm just saying just judging a driver (or any audio device) by brand name alone could be an error....

From what I seen so far from info and models Rojo posted - Kicker does look very good, but it's incomplete data so far...

 

[rojo]

Seems like Rojo has done a lot of work for you and those eminence drivers look promising. I would caution against the Kicker driver because do they tend to be oriented to SPL more than sound quality. Of course properly tuned it would still destroy most commercial subs.

If you are going to hire out the project. You might get the Infinity Kappa 120.9w and use the below thread which has all the heavy lifting done for you.

http://forums.audioholics.com/forums/threads/simple-12-infinity-kappa-vq-midq-plans.45528/

Even if you don't use the exact build it shows you how to properly fold a slot port and build a ported box.

I will say everyone seem to pushing ported, but I hope you at least give yourself a chance to hear both and determine your preferences. I myself tend to prefer sealed systems. One of the reasons we have so many options for speakers is that we all have different preferences.

The Infinity build you linked is tuned way too low. The Fs of that driver is 27.2Hz. There should be a dip in the excursion at that driver's resonant frequency, but the model has the dip at around 21Hz. If you're going to caution against orienting to range or SPL over sound quality, then the Infinity build should be your cautionary tale -- not the Kicker.

The worst part about the Kicker sub is that the brand is a common choice for teenage punks with too much bass in their cars. I've got the same prejudice, believe me. Just seeing a Kicker driver makes me want to yell, "Get off my lawn!" But if the T/S params of that Kicker Comp 15 are accurate, that driver should be very well controlled and musical, and a surprisingly good choice for home theater (assuming the required enclosure size isn't a deal killer).

It's really too bad he can't get the Dayton 18" HO driver. This build is a better demonstration of a build done right, I think.

 

[lsiberian]

Curious how you determine SQ vs SPL for a given driver? Aren't they a combined function with the amount of distortion resulting? I like sealed subs for size and ease of construction, but takes several of them to get somewhere....

SQ of a driver is typically measured by the flatness of BL/X. In subwoofer driver design one of the trade-offs is X-max and flatness of that curve. There is nothing wrong with going for volume if that's your goal, but it's a trade-off a designer makes. Kicker focuses on volume above all else. I see nothing wrong with that and I think what they've achieved is remarkable engineering. But I prefer drivers that sacrifice xmax for BL/X flatness.

I disagree that it takes several sealed subs to have an excellent system. I only have 1 and it does quite fine. The entire reason many drivers where engineered was to allow for sealed alignment. Once you actually load a sub in a room it really does help the low end a lot. A lot of amazing DIY drivers can't actually be ported properly.

 

[BoredSysAdmin]

It's really too bad he can't get the Dayton 18" HO driver. This build is a better demonstration of a build done right, I think.

Yes he can, but it could be a budget stretcher:
https://www.amazon.co.jp/Dayton-Audio-RSS460HO-4-Reference-Subwoofer/dp/B00SA8ROCQ/ref=sr_1_2?ie=UTF8&qid=1467752617&sr=8-2&keywords=dayton+HO

But no UM18 sub, best I could find is UM12 which is also quite expensive.
https://www.amazon.co.jp/Dayton-Audio-UM12-22-Ultimax-Subwoofer/dp/B01AOOB6ZO/ref=sr_1_2?ie=UTF8&qid=1467752664&sr=8-2&keywords=dayton+ultimax

 

[lsiberian]

The Infinity build you linked is tuned way too low. The Fs of that driver is 27.2Hz. There should be a dip in the excursion at that driver's resonant frequency, but the model has the dip at around 21Hz. If you're going to caution against orienting to range or SPL over sound quality, then the Infinity build should be your cautionary tale -- not the Kicker.

The worst part about the Kicker sub is that the brand is a common choice for teenage punks with too much bass in their cars. I've got the same prejudice, believe me. Just seeing a Kicker driver makes me want to yell, "Get off my lawn!" But if the T/S params of that Kicker Comp 15 are accurate, that driver should be very well controlled and musical, and a surprisingly good choice for home theater (assuming the required enclosure size isn't a deal killer).

There are actually people who argue for that type of design. Regardless the thread shows how to properly build a slot port. So I suggest at the very least learning about the build and construction side form it. It made a lot of happy people over the years.

 

[lsiberian]

Yes he can, but it could be a budget stretcher:
https://www.amazon.co.jp/Dayton-Audio-RSS460HO-4-Reference-Subwoofer/dp/B00SA8ROCQ/ref=sr_1_2?ie=UTF8&qid=1467752617&sr=8-2&keywords=dayton+HO

But no UM18 sub, best I could find is UM12 which is also quite expensive.
https://www.amazon.co.jp/Dayton-Audio-UM12-22-Ultimax-Subwoofer/dp/B01AOOB6ZO/ref=sr_1_2?ie=UTF8&qid=1467752664&sr=8-2&keywords=dayton+ultimax

No kidding. Does SI ship to Japan?

I think the Kicker would probably blow his mind anyway. going from no sub to a slot ported kicker is a huge upgrade.

 

[lovinthehd]

SQ of a driver is typically measured by the flatness of BL/X. In subwoofer driver design one of the trade-offs is X-max and flatness of that curve. There is nothing wrong with going for volume if that's your goal, but it's a trade-off a designer makes. Kicker focuses on volume above all else. I see nothing wrong with that and I think what they've achieved is remarkable engineering. But I prefer drivers that sacrifice xmax for BL/X flatness.

I disagree that it takes several sealed subs to have an excellent system. I only have 1 and it does quite fine. The entire reason many drivers where engineered was to allow for sealed alignment. Once you actually load a sub in a room it really does help the low end a lot. A lot of amazing DIY drivers can't actually be ported properly.

So how did the Kicker 15 show particularly in this regard vs the Kappa?

A single sealed sub may work well in a small sealed room depending on your spl/extension goals I suppose.

 

[rojo]

No kidding. Does SI ship to Japan?

I think the Kicker would probably blow his mind anyway. going from no sub to a slot ported kicker is a huge upgrade.

I suppose I should note that for a slot port, the vent needs to be 10"W x 2.5"H x 20 3/8"L for a tuning of 18.5Hz. Not sure how that will impact the internal volume displacement, whether the dimensions of the box need to be modified to accommodate the difference from the dual 4" PVC vents I initially suggested. Ultimately, it's not a horn or a transmission line, and it's probably still close enough for government work I think.

 

[rojo]

SQ of a driver is typically measured by the flatness of BL/X. In subwoofer driver design one of the trade-offs is X-max and flatness of that curve. There is nothing wrong with going for volume if that's your goal, but it's a trade-off a designer makes. Kicker focuses on volume above all else. I see nothing wrong with that and I think what they've achieved is remarkable engineering. But I prefer drivers that sacrifice xmax for BL/X flatness.

I disagree that it takes several sealed subs to have an excellent system. I only have 1 and it does quite fine. The entire reason many drivers where engineered was to allow for sealed alignment. Once you actually load a sub in a room it really does help the low end a lot. A lot of amazing DIY drivers can't actually be ported properly.

I'd like to understand this. Can you elaborate on "the flatness of BL/X"? BL would be the T/S param labeled as "BL", presented in units of "Tm" (Tesla-meters?), representing motor force factor, right? What is X?

Edit: I gather from this paper that "x" is voice coil travel. There's a lot of technobabble in that paper, and I'll have to read it a few times to begin to understand its meaning. Now I'm curious to know, how can you predict whether a driver has a non-linear BL(x) curve from its T/S params? What values indicate such a characteristic?

 

[sleepyhead]

An 18 inch driver is too big for my apartment, especially that one that RoJo linked. My room is quite small, but opens up to a bedroom on one side, a hallway on another side, and sliding window doors onto my balcony.

Any box I build or buy ideally should have one dimension of 40 cm (15.7 inches) maximum (45 cm is doable too), but the other sides can be as large as it needs to be. I really like the curve the Kicker produced, but that's only theoretical, right? I don't really care about how the driver looks (my centre is a completely different colour from my towers). The rough size outlined for the kicker is similar to the SVS PB-2000 that I had considered, but the PC-2000 was more easily placed within my room.

Taking cost into consideration of just the driver and amp, as BoredSysAdmin states, it's about $450 for the Kicker and Behringer iNuke NU1000. I could effectively get 2, and have them placed in my corners. That should eliminate any nulls, right? Going by the videos from Audioholics YT channel, I could run my single sub pre-out to the miniDSP, and have that throw 2 signals lines to the 2 subwoofers? I'm thinking too far right now. Whoops.

Back to the important parts, I do think that 2 of the Kicker is the way to go, or the Eminence, however the model shows a roll off that's a little early. Would it be possible to design a box that can roll off nearer the 20Hz mark? I'm after SQ rather than SPL, so it doesn't bother me too much if it can only do 95dB instead of 105+dB.

I also looked at JL Audio drivers (the W0 series), but the Qts is above 0.4. Same with Rockford Fosgate too. I've been going through a lot of the car audio subwoofers and I'll continue to do so until needed.

So far, for drivers under consideration:

• Dayton Classic 15
• Kicker C154
• Infinity Kappa 120.9w
• Eminence Lab 12C
• Image Dynamics ID15D2V.3 / ID12D2V.4

Powered by:

• Behringer iNuke NU1000 x2 (is the DSP version needed?)
• Behringer iNuke NU3000 x1

Weighing everything up so far, I'm excited by the DIY prospect! it may cost a little more than anticipated, and the cheaper / easier solution could be to buy the SVS PC-2000 or 2 RSL Speedwoofer 10S. However, I am enjoying the fact with DIY, I could get a box shape that will fit my room, and "tune" it to how I'd like it.

I'm leaning heavily towards DIY! What a slippery slope.

EDIT: I downloaded a program called WinISD to try modelling the drivers. I'm pretty sure I'm not using it right, but here is my attempt at modelling the ID15D4v3 in an 8 cu. ft. box with a slot vent tuned to 20Hz.

 

[lsiberian]

I'd like to understand this. Can you elaborate on "the flatness of BL/X"? BL would be the T/S param labeled as "BL", presented in units of "Tm" (Tesla-meters?), representing motor force factor, right? What is X?

Edit: I gather from this paper that "x" is voice coil travel. There's a lot of technobabble in that paper, and I'll have to read it a few times to begin to understand its meaning. Now I'm curious to know, how can you predict whether a driver has a non-linear BL(x) curve from its T/S params? What values indicate such a characteristic?

This is an extremely complicated engineering topic one I leave to those far more expert than myself on the subject. Below is a very good article on the subject written by a speaker engineer who does this for a living.

http://www.tonmeister.ca/wordpress/2015/12/18/bo-tech-why-select-one-driver-over-another/

Essentially BL is the BL of the driver over the movement of the cone. Flatter is better.

So how did the Kicker 15 show particularly in this regard vs the Kappa?

A single sealed sub may work well in a small sealed room depending on your spl/extension goals I suppose.

I don't have measurements either way for this driver and I am unaware of anyone that's used it in home audio on any of the forums. People have had success with the Kappa. I wouldn't buy either though. I'd get a proven home audio driver that's been used in a lot of builds with great success.

An 18 inch driver is too big for my apartment, especially that one that RoJo linked. My room is quite small, but opens up to a bedroom on one side, a hallway on another side, and sliding window doors onto my balcony.

Any box I build or buy ideally should have one dimension of 40 cm (15.7 inches) maximum (45 cm is doable too), but the other sides can be as large as it needs to be. I really like the curve the Kicker produced, but that's only theoretical, right? I don't really care about how the driver looks (my centre is a completely different colour from my towers). The rough size outlined for the kicker is similar to the SVS PB-2000 that I had considered, but the PC-2000 was more easily placed within my room.

Taking cost into consideration of just the driver and amp, as BoredSysAdmin states, it's about $450 for the Kicker and Behringer iNuke NU1000. I could effectively get 2, and have them placed in my corners. That should eliminate any nulls, right? Going by the videos from Audioholics YT channel, I could run my single sub pre-out to the miniDSP, and have that throw 2 signals lines to the 2 subwoofers? I'm thinking too far right now. Whoops.

I just looked at Amazon japan and you can get Dayton Audio Reference drivers.

https://www.amazon.co.jp/Dayton-Audio-RSS390HF-4-Reference-Subwoofer/dp/B01CDUZ9L4/ref=sr_1_6?ie=UTF8&qid=1467816761&sr=8-6&keywords=dayton+audio+reference

Unfortunately this one needs a 21.37 inch cube, but it hits 32.3 F3 in a sealed box which is very impressive. It also has 19.5 Fs if you ever want to port it someday.

https://www.amazon.co.jp/Dayton-Audio-RSS315HFA-8-Reference-Subwoofer/dp/B01DQBXXB2/ref=sr_1_5?ie=UTF8&qid=1467816761&sr=8-5&keywords=dayton+audio+reference

This one needs a 17.6 in cube with a 35.2 F3 which seems to be close enough to your dimensions.

 

[rojo]

Any box I build or buy ideally should have one dimension of 40 cm (15.7 inches) maximum (45 cm is doable too), but the other sides can be as large as it needs to be.

Aw snap. That dimension limitation will be width or depth I bet. Probably be best if you concentrate on smaller drivers, then. As if this weren't challenging enough.

Would it be possible to design a box that can roll off nearer the 20Hz mark? I'm after SQ rather than SPL, so it doesn't bother me too much if it can only do 95dB instead of 105+dB.

Think of the rolloff more as max output. The response will tend to be flatter at lower wattages and with room gain added. Especially if you corner load your sub(s), you'll get extra boost toward infrasonics before your driver reaches its excursion limit. With that in mind, 95dB at 20Hz is pretty easy. But on the other hand, there may be nulls and modes at various parts of your room, so the model only indicates a vague hypothetical idea of how it will actually sound once you build it.

Taking cost into consideration of just the driver and amp, as BoredSysAdmin states, it's about $450 for the Kicker and Behringer iNuke NU1000. I could effectively get 2, and have them placed in my corners. That should eliminate any nulls, right? Going by the videos from Audioholics YT channel, I could run my single sub pre-out to the miniDSP, and have that throw 2 signals lines to the 2 subwoofers? I'm thinking too far right now. Whoops.
...
I'm leaning heavily towards DIY! What a slippery slope.

I like how you think! And I think I have a brilliant idea for a perfect fit. Would you consider a Sonotube sub? From your home improvement store, get a concrete form tube with dimensions of 12" dia x 48" L (30.5cm dia x / 122cm L), something like this. It's strong, it's cheap, and I can model a system that works without your even having to cut it. Just flare a 4" PVC tube (do a YouTube search for "flare PVC" and you'll see how to do it), build a top and bottom baffle + feet and a table top, insert your driver into the bottom and the PVC vent in the top. It takes up only a square foot of floor space, sits about 4 1/2" tall, and will hit >100dB ground-plane at 20Hz with the right driver and amp -- significantly more than that if your 1 sq. ft. of floor space happens to be in the corner.

Here's what I have in mind:

REXv2-10 -- 30,240円

Full details when I get back from lunch. BBL.

 

[lovinthehd]

This is an extremely complicated engineering topic one I leave to those far more expert than myself on the subject. Below is a very good article on the subject written by a speaker engineer who does this for a living.

http://www.tonmeister.ca/wordpress/2015/12/18/bo-tech-why-select-one-driver-over-another/

Essentially BL is the BL of the driver over the movement of the cone. Flatter is better.



I don't have measurements either way for this driver and I am unaware of anyone that's used it in home audio on any of the forums. People have had success with the Kappa. I wouldn't buy either though. I'd get a proven home audio driver that's been used in a lot of builds with great success.



I just looked at Amazon japan and you can get Dayton Audio Reference drivers.

https://www.amazon.co.jp/Dayton-Audio-RSS390HF-4-Reference-Subwoofer/dp/B01CDUZ9L4/ref=sr_1_6?ie=UTF8&qid=1467816761&sr=8-6&keywords=dayton+audio+reference

Unfortunately this one needs a 21.37 inch cube, but it hits 32.3 F3 in a sealed box which is very impressive. It also has 19.5 Fs if you ever want to port it someday.

https://www.amazon.co.jp/Dayton-Audio-RSS315HFA-8-Reference-Subwoofer/dp/B01DQBXXB2/ref=sr_1_5?ie=UTF8&qid=1467816761&sr=8-5&keywords=dayton+audio+reference

This one needs a 17.6 in cube with a 35.2 F3 which seems to be close enough to your dimensions.

So in other words you don't know....thanks.

 

[rojo]

Alright, here's my (possibly brilliant, possibly foolish) idea of putting an RE Audio REXv2-10 into a 12" x 48" concrete form tube.

Build this:

The concrete form tube is 12" outer diameter, 11.5" inner diameter, and 48" long. Don't bother cutting it. It's already the correct length. I'm hoping Japan uses the same concrete form tubes we Americans use. If not, let me know what you've got that's reasonably similar and I'll try to recalculate.

The bottom baffle woofer cutout is 237mm diameter. See this PDF for full dimensions and T/S params. For the top of the vent, you can router a flare into the wood. The bottom of the vent can be flared using a metal mixing bowl and a heat gun. Search YouTube for "PVC Flare" to watch others demonstrate. Hopefully the rest is illustrated well enough that you see how it all fits together. You can make the floor plate and top cover plate a little larger if you wish, for greater stability and a larger table to throw your keys onto. You might also consider fixing a chicken wire gate over the vent to prevent things from falling into it.

You should end up with this. The bold lighter green is 200W unfiltered. The darker, thinner green has a couple of simulated EQ filters to prevent overexcursion.

Filters:

Frequency response:

Cone excursion (red line = Xmax):

Impedance:

Vent air velocity (meters / second):

That looks a little on the high side for chuffing, but that is at full power. At a more typical 100 watts of output the vent air velocity peaks at around 14m/s, or a little over mach 0.04. And flaring the vent will further reduce turbulence.

And if you build a pair, you'll net an additional ~6dB output.

 

[sleepyhead]

I'm posting from my phone as I took a little trip to コーナン, a home depot like store. I found some things that could work for a sonotube.

Tube is 300mm x 1m or 2m
PVC port 75mm or 100mm or 150mm x 1m

Attached are pictures.