Eminence Kilomax Pro-18A

[carpenter]

I'm new here, but love what I see... You're my kind of people!

Using WinISD, I've been modeling the Kilomax Pro 18A. I like the results and wonder how everyone feels with regards to how it stacks up against the competition. Because I'm my own best customer, I've become an Eminence dealer. Hence, I'd like to use Eminence products if they fit the bill. Point of interest: wholesale price will cost me more than the upcoming driver that ThomasW. has mentioned in other threads. So, it's not like I'm cutting a fat hog...

Best regards,

John Inlow

[ThomasW]

As per the FAQ standard accordion surrounds and low Xmax drivers aren't recommended. (and yes 9 mm is a low Xmax for what we're doing)

Darrel at Hawthorneaudio.com is developing an 18" with a specialized surround and higher Xmax made by Eminence that may fit our needs.

Here's a link to a thread about Darrel's driver
ibsubwoofers.proboards51.com/index.cgi?board=talk&action=display&thread=1144896203

[carpenter]

The FAQ does not offer definite physical measurements. So your "As per the FAQ" statement makes me bristle a bit.

Eminence woofers are amazing. If a rubber or foam surround is necessary, I'll explore further. 9mm Xmax isn't bad if you have enough drivers. It's the QUANTITY of air being moved, I belive I read.

It appears from other member's posts that an Xmax of 12mm is standard. Am I correct?

All other features of the Kilomax appear to be in line with IB requirements, yes?

John Inlow

[Darren]

12mm is still pretty slim in my opinion. I'd want something closer to 18 or 20 myself.

I'd pay particular attention to ThomasW's suggestions and recommendations.

Check out these drivers specs for something to compare to:
www3.sympatico.ca/bonaz/IB-Sub/IBdrv-01.htm

[carpenter]

I'm all for suggestions and recommendations. I don't do well with condescension.

Thanks for the link.

John Inlow

[ThomasW]

This forum was on a different server until last fall when the forum was moved to this new host. Unfortunately the archived version of the old forum was lost during the move.

On the old forum there were several discussions with people buying drivers having accordion surrounds, and having them 'chuff' at higher SPL's. As a result of these issues, FAQ states to avoid accordion surrounds.

Obviously if you want to wallpaper an area with drivers or use 8-18"s like William Cowan's design in Australia, then it doesn't matter what kind of surround the driver has...

We've never recommended a driver with an Xmax as low as 12mm.

The Eminence 18" that Darrel is having made, has more than 14mm of Xmax and is using a special accordion surround that according to Darrel won't chuff. Since they're in the beta test stage I don't have any hands on experience with them...

The FAQ and the suggestions/recommendations are based on quite a few years of experience, (30+yrs building subwoofers) and are designed to guarantee proper performance. Obviously anyone can build whatever they desire...

[carpenter]

Obviously anyone can build whatever they desire...

The intent of my post was to gather opinions and information. Some of this information is difficult to locate directly. Hence, the return posts. I appreciate your information, Thomas. But, it felt like you were scolding me for not reading the FAQ--which, in fact, I have. I may not remember everything I read, but I try. I thought you might want to know how your were percieved.

John Inlow

[carpenter]

A day at the races...

I've been playing around with WinISD. I don't know how much stock everyone places in this software. It certainly offers interesting results.

After being enlightened by ThomasW, I was totally prepared to drop the Kilomax as a contender. Really. I read on and located the "proper" drivers to use. The name, Sound Splinter, cropped up; it is powerful, affordable, beautiful. Coincidently, I noticed that Win ISD has the Sound Splinter RL P15 loaded and ready to run with the merest flick of the mouse. It also has the Kilomax 18... hummm.

I did the following: 8 of each brand were assigned separate, 2000 foot, sealed enclosures; both sets were equalized to optimize the first octave, Q and gain were adjusted in the eq as necessary to roll off with 3db down at 17 cycles. Afterwords, I adjusted the input signal to achieve full Xmax in both sets of drivers.

Some things are easy to predict:

Yes, the Sound Splinter will handle significantly more wattage, but, then again, it has to. It's cone is smaller than the Kilomax 18 and the unit has less initial efficiency. No surprise there. What did surprise me was the performance. It reminded me of drag racing; the brutal big block slugging it out against a stroked small block with muscles! At the finish line, the performance curves were nearly identical, back and forth they ran--a whiskers width apart from 17hz and up! In the outer field, the Sound Splinter pulled away at 10hz by 5db. Very impressive!

In the end the 8 Sound Splinters required 370 watts to reach full Xmax. The 8 Kilomax drivers required 45... Both enclosures delivered 119db with nearly identical performance plots. Also interesting--while on the Xmax chart, I noticed that the Kilomax peaked at 18hz and then quickly rolled off, away from the Xmax boundary, implying that perhaps the lower frequency won't harm the driver. I'm not certain. The Sound Splinter, on the other hand, followed the Xmax limit at 18hz, and to the very bottom end of the graph.

Isn't curiosity a blast? Now I'm really screwed up

John Inlow

[ThomasW]

The recommendations in the FAQ and those recommendations posted by me are designed to do a few things. First and foremost is to guarantee that anyone following them will successfully build a good IB the first go around.

To ensure success for the absolute neophyte, all the recommendations error heavily on the side of a conservative approach to the design. One example of this is the use of multiple drivers with high Xmax.

Those knowledgeable about the reproduction of very low frequencies can and do use their best judgment when it comes to the design and implementation of their IB's.

Re: your examples, fundamentally any approach used to obtain high enough displacement works (most of the time) since primarily it's all about displacement when it comes to reproducing low bass. With IB's the efficiency goes up as the frequencies being reproduced go lower. This situation quickly uses up Xmax. However one must be careful using computer sims as the only guide for designing their IB, because other design factors are also important.

For example....

As function of their design, drivers like the RL-p15, the AE IB15, AV15, and a few others, are very tolerant of being overdriven (virtual, but not quite literal 'bottom-less' design). That type of operational safety is not inherent in many other mfgr's designs.

A further advantage to aluminum cone drivers like the RL-p15 or those drivers with epoxy/Kevlar reinforced cones, is their ability to maintain linear (pistonic) cone operation when being driven hard (something problematic with large standard pulp cone drivers). Linear cone motion is beneficial when the goal is the highest sound quality.

[carpenter]

I'm glad you made reference to the operating margins of the Sound Splinter and similar drivers.

I gives me pause to consider the Kilomax unit...

I discovered that the Xlim of the Kilomax 18 is about 3/4". This gives an inch and a half total--right? Well, anyway, I used this parameter in the plot description I gave, above. Eight of these drivers may Xmax at 45 watts, but their Xlim doesn't occur until driven with more than 650 watts. I didn't realize this. Another thing I didn't realize is that Eminence rates Xmax very conservatively. So now I'm wondering if we're not comparing apples to oranges. Who knows? Their Xmax can be based on 10 percent distortion limits. I didn't know this. I always thought it was related to the amount of voice coil hanging out of the magnetic gap. Of course, both are related, now, aren't they?

I own a pair of Hafler P-7000 amplifiers, more than ample to drive eight woofers. These amps have a tremendous dampening factor. I believe in excess of 600 below 1000hz. Fantastic control over the woofer.

Thanks for sharing your opinions with me, Thomas. I'll keep you posted on my progress with the Kilomax. I do feel adventurous.

John Inlow ;D

[ThomasW]

I was looking at the Kilomax vented application pdf from the Eminence website, and saw Jerry McNutt's name on it. McJerry (his nickname) has been a IB 'cult' member since the beginning of the forum in 2000. You might want to email him and continue this discussion.
www.eminence.com/pdf/cab-kilomaxpro-18a.pdf

[carpenter]

Thanks for the tip, Thomas.

I've been looking at the Dayton 15 inch units from Parts Express; same performance, almost half the price.... hummmm. Any comments on the DAYTON DVC385-88? WinISD gives this baby a big thumbs up; it's capable of 119db @ 100watts input w/8drivers. These guys are selling for $118.00 apiece in lots of 4. Man...

John

[ThomasW]

They're okay, a semi-clone of the original Adire Tempest, (both made by Eminence). Basically a state of the art design in 2000.

The one's I've seen lately don't seem as well made as the older units. That's not a major problem given PE's 5 yr warranty and customer service.

[carpenter]

I don't know you well enough to know what "They're ok" means. State of the art within the last decade sounds positive enough.

BTW, I edited my prior post just as you submitted yours.

See... my head can be turned. Although, I have learned over the years that lower priced products can get you into trouble. This is where your opinion is really useful.

Thanks,

John

[ThomasW]

Okay meaning they're an average speaker in todays world.

Unfortunately there's a dearth of good modest cost speakers at this particular time.

In a few months John J of AE speakers will be offering his AV-15"s again. www.aespeakers.com/ These are similar to the RL-p15" but less money. That's a picture of one on the webpage. The site is down until he has more inventory

One option might be the $210 ea Arsenal 15" preorder from
www.ascendantaudio.com/arsenal15specs.html
At their regular list price they're not as good a deal as the RL-p15". But the preorder pricing is attractive

[carpenter]

...and then again, there's that little gem you've got under wraps...

I'm not going to be ready for another six months. I can afford to wait and see what you've got up your sleeve.

I have to get the final inspection on my addition. The multi-media room happens to be located in the inspection area. I don't want to have to explain to the county why there are big holes in my floor... I laid awake thinking about fire blocking issues and wondering if I'm violating code by only having a membrane as delicate as a speaker cone between my garage and the media room. Something to chew on, isn't it?

Best regards,

John

[cowanaudio]

G'day Carpenter and ThomasW

I'm a bit late but I guess I should chime in because I've walked this road before.

The 8 by 18" sub that is shown on my webpage is a result of the lack of high quality of drivers in Australia at the time (2000). Product made in the USA was way over priced, and the range was poor too. I guess Thomas had similar problems when he designed his first IB. To put it all in perspective, this sub was probably the first manifold IB in Australia, but is still giving excellent service, and has become the last of many subs for the owner.

The 18Sound 18LW1400 drivers I used have a very low distortion motor (two copper faraday rings, very thick top plate and FEA designed gap), and are essentially noise free up to +/-10mm excursion. They can handle +/-25mm before damage. (X-max is +/-9mm)

Eight of these drivers provided the high levels of output required between 10 and 40Hz and were essentially unbreakable, even when driven with a heavily clipping amplifier. My customer (who lives in Melbourne, Australia) is delighted with the ultra clean, low and loud bass that was essentially hidden from the room. The odd oops has caused little more than dirty undies.

Now, would I do it this way again? No. The choice of drivers have improved greatly over the last 6 years. It is possible to obtain this amount of displacement for far fewer $$$. Many of the newer drivers don't offer this level of abuse resistance, though. Also the 18LW1400 drivers require a LOT of eq to flatten the response. A driver with a lower FS and higher QTS would require far less or even no equalization.

So I guess it would be possible to obtain a good result with enough Eminence Kilomax drivers, but now there are cheaper and easier ways. I recently used a pair of the Sound Splinter RL P15 in a vented subwoofer, and have a lot of respect for the driver. If I were doing another high end IB I would most likely use this driver. Care would need to be taken to ensure the driver could not be damaged by over driving it. The pro drivers are much harder to break, or even upset.

Cheers

William Cowan

[ThomasW]

Hi Bill,

Thanks for stopping by....