[Greg0]

Hi guys,

I have just ordered a new FTW 21 and now am in need of some design help for a suitable box.
I am going for a large ported enclosure of around (but not limited to) 20cuft tuned to around 15hz, I want this thing to shake the house!

Mainly it will be used for HT but occasional music, my current sub is a 2 cuft sealed Boston Acoustic G5 12” (a truly underrated sub)

Attached is a couple of Winisd plots,
• 20cuft @ 15hz (Blue)
• 20cuft @ 12hz (Red)
• 10cuft Sealed (Yellow)

The 15hz tune seems to give the best response, however Chrapladm very kindly advised me that with a 12hz tune I will not need a HP filter.

I am thinking of contacting Graham (gperkins1978) and using his design service however I would like to publish all of this design online for others to use.

The reason being, I believe there are people out there who may overlook certain drivers purely because there aren’t many plans available.

And really, companies like IST really only exist in the DIY world…

Any thoughts?

Also, If there are any Aussies out there looking for the IST drivers, they are being imported by Sam at Affordable Drivers (Becoming Infrasonic Au) – Big thanks to him for looking after me

Thanks,
Greg

 

[Mauritzvw]

Subscribed! Price?

 

[chrapladm]

Subscribed! Price?

I think you can do a preorder and save some money when ordering the 21" subwoofer from Affordable drivers. I think they are about 715 dollars each but best to give them an email.

 

[Mauritzvw]

No worries. Cheers.

 

[Greg0]

Subscribed! Price?

$649
Sam gave me a very good deal as it was a pre-order, he has 6 arriving on the 15th, i just spoke with him and the special is still running not sure how many are available though..

He may, be able to combine shipping with mine and save you a little.

The driver is not up on their website but drop him an email through the affordabledrivers.com.au website

Greg

 

[Mauritzvw]

I don't have space for an enclosure to do it justice unfortunately.

 

[Greg0]

So Does anyone have any opinion on either 12hz 20 cubes or 15hz 20 cubes?

What do you guys think will give the best low end ?

 

[chrapladm]

Depending on room gain I would think you would be happy with the 12hz tune for ULF or the 15hz tune. The 15hz tune will add more slam above the tune when compared to the 12hz tune but I am also not sure what you are used to. And being only 3 more HZ difference I think you should just compare 10hz tune vs 15hz tune.

 

[Greg0]

10hz? Another spanner in the works!

I'm a bit worried that 10 hz might make it unsuitable for music even with an eq..

Having never even seen a subwoofer of this size let alone heard one I am completely at the mercy of people like you who are much smarter than me!

 

[chrapladm]

LOL.....I am just using my pair of 21's in a sealed 6cuft cabinet. Mine will sound fine for me with music but I also have mains that will play down to 40hz just fine. I am also going to be adding four more 15's as soon as they come out. So I am adding as many speakers as I can but I like sealed cabinets myself.

You could always do a multi-tune cabinet like gperkins did with his Fi Q 18's. I think he had a subwoofer cabinet with 3 slot ports and with the 3 combination ports could tune it to 12hz-17hz and have the option of sealing it also.

Just a thought.

 

[ironglen]

If this will be the only sub, you desire high output, and you need crazy output because it's a huge space and you don't get room gain, I'd recommend 20hz tune with 17hz hpf. Model it and compare to 12hz (low enough to go without hpf) and you'll see why I want you to look at it. On the other hand, if the lone 21 is enough output with the 12hz tune, with room gain, then I recommend 12hz rather than 13-18hz; as stated, you won't need a hpf and output is only marginally lower.

The LLT will sound good, only the placement limitations have the potential to limit musicality since it is so large, something to consider.

Looking forward to your build :T

 

[Greg0]

Thanks for the suggestions guys

I like the sound of a multi tune box, although a very complex design..

Attached is my WinISD plots, not sure what i have done wrong (different computer) becuase its indicating even with the 12hz tune that i will be exceeding Xmax with 1500W?
I put a 2nd order BW at 17Hz on the yellow, which tames that massive peak at around 25hz

The room it will be in is quite large & open, however its not going to stay there for ever.

Yellow = 20cuft 20Hz
Blue =20cuft 15Hz
Red =20cuft 12Hz

Regards,
Greg

 

[chrapladm]

After finally simulating I stand corrected. You should not need a Hpass with 1000watts. With your electronics falling off at around 10hz you will not be getting a full signal to your subs.

Now with 1500 watts you are definitely hitting Xmax.

 

[Greg0]

I will be powering it with a inuke NU3000 DSP, which supposedly is good for 3000W bridged into 4 ohms.. Not sure how accurate that is..

Are there any negatives (apart from complexity) of doing a multi tuned box?

 

[chrapladm]

When gperkins did his multi tune ported sub I thought it was an awesome idea. You get all the different tunings and can still seal the subs if need be. The only bad thing I saw about it was the enclosures are big.

But if you have the room then I dont think there are many negatives. I also think multi-tune is good for getting the most out of your subwoofers if you only have a pair of them.

 

[Diamonddelts]

I will be powering it with a inuke NU3000 DSP, which supposedly is good for 3000W bridged into 4 ohms.. Not sure how accurate that is..

Are there any negatives (apart from complexity) of doing a multi tuned box?

I would definitely go for the NU6000 with DSP. My best is to always go with the flagship amp of any Behringer line. Their specs are so inflated. I've used a NU6000 and it has the minimum amount of power needed for these 21's. Don't go with the NU3000 where they might be starved for power.

 

[Greg0]

Thats not good! Anyone looking to buy a inuke NU3000DSP??

I do find it hard to believe its rated so high, It weighs less than my EQ.. not even a heatsink!

the more i read, the more i love the LG Clones, Im not sure if anyone has brought one into Australia, costs would be pretty high i think!

ill see how it goes, It seems to be ok with my G5, although a 21 is a different story..

also i have PM'ed Graham to see if he is willing to help me out with the box design, too bad you guys don't offer design services!

 

[chrapladm]

I dont have the skills graham does. But I will be getting 2 LG clones soon. I will be ordering one for my L/R and another for my center and subs.

If you DO use a clone make sure you DO use a Hpass.That amp will definitely power all frequencies past your tune. lol

 

[Greg0]

I wouldn't be that modest! I've read quite a few of your posts and I regard your opinion highly.

2 clones? It would be interesting to compare your 3way and LG clones with the real deal!

How much did you pay for the LG's if you Don't mind me asking?

 

[chrapladm]

LG's have not been ordered yet. I was wanting to finish my 3 way build and then order the first clone amp. That will power the mid and bass part of my 3way. The 14K is $726usd +125usd. The 10Q's are 785usd + 125.

Prices are direct from Sanway. I seem to be emailing them constantly about their products. I wont be ordering my clone for another three weeks. So you might have yours before I do.