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[Art Welter]

I'll look into these as a final solution.  I don't mind spending money as long as there's something in return (and I'm making a little bit).  Somebody will know the optimum cabinet size for maximum volume around here, right?

Again, how the heck do I know I'm literally at the breaking point?  SPL or watts measured with a Killawatt?  It's an honest question.
Thanks,
Greg

The clicking noise was an obvious indication you had exceeded the speaker's mechanical limit (Xlim) which is 19.2 mm, about .75" of travel in each direction.
The Xmax (linear excursion) for the Kilomax is 10 mm, so if you were to notice the cone moving more than 7/16" forward, or just over 3/4" peak to peak it would be time to back off a bit. Above Xmax, the speaker will not get much louder, though distortion will increase, making for more apparent "loudness".

The B&C 18SW115 has an Xmax of 14mm, and an Xlim of 30mm.
In addition to much greater excursion, it's Vas is 6.5 cubic feet, compared to the Kilomax at 11.71 cubic feet. Vas is the equivalent volume of air that has the same "springyness" as the driver's suspension, in other words the 18SW115 is twice as stiff, it is nearly impossible to hit Xlim.

If you decide to go the DIY route using a 18SW115, my Keystone sub design would be a good choice, and is about 6 dB louder than the 18SW115 in a ported cabinet.

Art

[Kevin McDonough]

hey

yeah, the Kilomax drivers are a bit of a hype monster, and don't really live up to it. I made the same mistake about 10 years ago as you did.

As someone said, they only way they soind any good is in a huge box around the 600 litre mark, anything else and while they can handle 1000w of heat building up during use, their other parameters let them down badly.

There are several very good drivers from BMS, eighteensound or B&C (among others) that will all do a MUCH better job for your application than the kilomax.

Also, while I realise you already have an amp and box and it seems a shame to waste these, as people have said another route to seriously consider is buying a powered box. Having a driver in a purpose built/matched box, with a matched amplifier which has all of its limiters and EQ etc already set appropriately, can make a massive difference and save a huge amount of hassle.

Often powered subs can be a bit of a disappointment compared to their matching tops (QSC and Yammy's aren't great  ) but the SRX series and models ending XLF, both from from JBL, seem to get excellent results based on peoples experiences.

xx

[g'bye, Dick Rees]

When DIY becomes DI2Y...

[Greg_Bell]

Greg, sorry about your trials here.  Expensive lessons are the most painful, but the best remembered, I guess.

Speaker damage gets easier your amp gets larger. Yes there is an old wives tale about amps that are "too small" being more likely to cause damage, but as you discovered, that's BS.

Early on I owned some Yamaha SW series subs and they were fairly underwhelming. A different set of drivers may help, but there are more factors in speaker design than sticking a big driver in the box you happen to have, and even then, you have to figure out how to tune them and have some kind of limiting mechanism to keep from cooking them again.  Setting limiting correctly so you are getting the right balance of full performance but preventing damage is very hard, and usually requires destructive testing. 

I would suggest you put your money toward a pair of self-powered subs. Spending $1000 on the big drivers mentioned doesn't make sense when you will still only have the low-end Yamaha enclosures.

Take a look at the JBL PRX-718XLF boxes, or search around for opinions on other good self-powered boxes.  They will sound better, play louder, and be MUCH harder to damage. The sale of your XTI plus the $1000 previously earmarked for big drivers should get you fairly close to a pair.

Tom,
In the last 72 hours I concluded I'd need a lab and a degree and a woodworking shop to dive into this and get an optimum result.  I guess the self-powered subs have come a long way since those powered Mackie 18"s that worked for a while...

I had hoped that Audio Architect would help me a great deal (and it is a good program), and I was willing to suspend my doubts about the Yammi enclosure until it shook apart...

Part of me wants to look at this as a challenge to dig into.  As a pilot was overheard to say about a colleague who had a bad outcome in bad weather, "He ran out of experience".  Me too, this time.  Now I'm starting to comprehend how large this subject really is.

[Greg_Bell]

Power handling is NOT an easy subject.

The speakers are tested for spec in one way (free space)-but then used in a completely different way (in a box of some sort-there are many different types that yield different results).

It is done this way because of way the standards are written and the manufacturer has no way of knowing what sort of cabinet it will be used in.

Also your source material is not a constant signal, but very dynamic.  This makes is A LOT harder to figure out what "wattage" is going to the speaker.

Also the fact that the impedance changes with freq, adds a whole new level of complexity to the equation.

Very often HOW IT IS USED, is more important than the actual size of the amp it is used on.

There are no simple answers to this very complicated subject.

It wasn't until I started reading spec sheets way more closely 8-9 years ago that the concept of impedance changing with frequency sunk in.  Whoa!  What voodoo is this?

Subs may be easily as complex as tuning a guitar, and that's no joke!!

There's no such thing as one-size-fits-all.

[Greg_Bell]

The worst part of the yamaha subs is not the driver. Its the box itself. It's weak, flexible, small, and the ports are too small to be used as a real sub. 20 years ago when they were designed we didn't ask our subs to do what we are doing today. You need a whole new sub system if you want modern performance.

Eminence sold a ton of Kilomax drivers because they look so cool. And that heatsink goes a long way towards making them handle a lot of "power". Unfortunately, they don't make a ton of noise with that power.

Kilomax's need a large box with a large port to work right. They can sound good with the proper box, but most people didn't want a refrigerator-sized sub to move around.

I imagine that the kilomax quickly overwhelmed the meager port in the yamaha box and essentially became unloaded which lets the cone flop around until it breaks apart.

For your next adventure I would ask someone here, or Parts Express to help you get some real subwoofage happening. I would start by reconing the original yamaha drivers and selling the 118's to get/build something better.

The good news is that the original Yamaha (Eminence) speakers are undamaged and back in the cabs of of this afternoon.  Please don't answer this question as it's something I should look into until I understand, but I thought the Eminence specs implied that power handling decreased as cabinet size increased?  Again, the noob in me finds this counterintuitive, but the smaller cabs were rated for higher wattages.

I do have to look into "loading/unloading" a speaker.

[Greg_Bell]

By the time you have 'experimented' trying to find a driver which will give you more of what you want to fit the boxes you have - which might never happen - you would be better off looking for a pair of PRX718's  as TJ suggested or KW181's or similar.... Maybe go used. You'll save money in the end what with all the failed experiments ....

I hear ya!  I know what I've got can't be optimized, but one consideration of the path I took was a very modest weight increase from the existing setup.  Some of these powered subs are starting at 81 lbs and heading to 145 lbs.

It's amazing what we do to play C, F and G on any given night...

[Greg_Bell]

^^stay away from the elx118p
I sold both of mine and replaced them with a single Srx828sp, what a difference!!

Sent from my D6708 using Tapatalk

I bet that thing rocks!  At 145 lbs, where are the wheels??

[Brandon Scopel]

On the back.

Sent from my D6708 using Tapatalk

[Greg_Bell]

The clicking noise was an obvious indication you had exceeded the speaker's mechanical limit (Xlim) which is 19.2 mm, about .75" of travel in each direction.
The Xmax (linear excursion) for the Kilomax is 10 mm, so if you were to notice the cone moving more than 7/16" forward, or just over 3/4" peak to peak it would be time to back off a bit. Above Xmax, the speaker will not get much louder, though distortion will increase, making for more apparent "loudness".

The B&C 18SW115 has an Xmax of 14mm, and an Xlim of 30mm.
In addition to much greater excursion, it's Vas is 6.5 cubic feet, compared to the Kilomax at 11.71 cubic feet. Vas is the equivalent volume of air that has the same "springyness" as the driver's suspension, in other words the 18SW115 is twice as stiff, it is nearly impossible to hit Xlim.

If you decide to go the DIY route using a 18SW115, my Keystone sub design would be a good choice, and is about 6 dB louder than the 18SW115 in a ported cabinet.

Art

Art,
I just saw your 81 page post on the DIY site.  I haven't read it all (yet!) BTW, 6dB is a LOT.  It looks like a tall cabinet, and my tops are always on subs.  At 45" tall, I'd worry about anything on top.  With all the small clubs out there, space is at a premium and it's tight for even a humble 3-piece.  We have clubs where one side of the PA is plenty.  But where's there's a will, there's a way.

The Kilos got to the shop today, and I found it dismally comforting that he has reconing kits in stock...  We confirmed that the voice coil did slam into the backplate.  One kilo was completely open and the other right behind it.  You could see the damaged wire.

I'm going to try to make what I have work while I plan an ultimate solution.  Self-powered subs get heavy quickly, and I seem to own the Mike Tyson of power amps, so...  I could find a good cab for the Kilos unless the only alternatives are giants, and I could keep the Yamahas stock and run all four subs off that amp for an outdoor gig.

I think you make an excellent point about measuring the travel.

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