New HT prototype sub!

**NDMstang65** · **08-04-09, 10:26 AM**

Hey guys!

Finally getting around to where I have some time to get some odds and ends projects done. I remember you all asking for a "Supersub" of sorts, so I'm playing around with the idea. Pictured below is a proto I just finished putting together so I don't have parameters, price points, or anything of that nature. Just wanted to stick a picture up and get your thoughts on it. We're looking at about 3" of excursion low tuned ported box type woofer with this. We can probably do it for IB as well for those who may be interested, but again without having the parameters done off of this one that I just built I can't say 100%. There would be more machining and such involved to get it to be an IB. There is an inductance ring inside of the motor with dual spaced progressive spiders. I'm going to be diligently working on a specific HT line for you guys with an array of neat new products. Coil will more then likely be a single 4ohm and single 8ohm.

Thoughts? Comments? Suggestions? Again, I do not know a price point right now as I just got this together after doing a little modeling, I'll know more in the coming weeks as far as specifics. I wanted to get initial thoughts from any of you guys.

Thanks!!
Nick Morgan
Fi Audio

**Sonnie** · **08-04-09, 12:16 PM**

I think I heard someone say 3 inches of excursion...

**onebadmonte** · **08-04-09, 12:51 PM**

Sexy looking sub. Any possibilities of having a passive radiator to go with that sub? Will this be available in a 22"? Thanks for the pic, sounds like exciting times in the HT world with Fi. Keep it up. =]

**Mike P.** · **08-04-09, 06:43 PM**

Quote:

Sonnie wrote:

I think I heard someone say 3 inches of excursion...

I imagine that would be both ways, peak to peak.

I like it, it looks good. I'll be waiting for the specs are to see how this beast models. Looking forward to it!

Is that the same basket design as the Ascendant Audio SMD?

**Fi Audio** · **08-04-09, 10:10 PM**

Definitely peak to peak. Surround limited on this design.
With Nick in house full time now he is taking care of some of the smaller "fun" projects that I have had on the back burner. I have had the design done for a while, but just havent had time to really get things together. Uses 8 3/8 magnets with a very healthy 1/4" thick inductance ring inside. Trying to keep things to a "supersub on a budget" with this one. It doesnt seem like from early feedback that most people would want a mega inductance ringed 5" p-p monster if it was going to cost what a mega inductance ringed 5" p-p monster would normally cost

Yes, same basket as the SMD. Although a completely different beast. It looks like the HT lines we do for Fi will be the only ones seeing this basket. Outside of that it will be on the AA lineup and one other OEM car company we build for (and slated for 2 other HT companies, but with them it wont be seen). Trying to keep that basket to the AA lineup as much as possible.

Thanks,
Scott

**filtor1** · **08-05-09, 03:32 PM**

Beautiful! I look forward to seeing where this goes. Been aching to do a single 18".

**Ricci** · **08-05-09, 03:50 PM**

Quote:

Fi Audio wrote:

It doesnt seem like from early feedback that most people would want a mega inductance ringed 5" p-p monster if it was going to cost what a mega inductance ringed 5" p-p monster would normally cost

Thanks,
Scott

I would!

Of course with the economy being what it is lately and something like that being low volume/ high manufacturing cost...I can understand. Supersub on a budget is a good goal. I look forward to more info...

**slim2fattycake** · **08-05-09, 11:26 PM**

Quote:

Ricci wrote:

I would!

Of course with the economy being what it is lately and something like that being low volume/ high manufacturing cost...I can understand. Supersub on a budget is a good goal. I look forward to more info...

x2. I'll be definitely tuned in for this.

**looneybomber** · **08-07-09, 08:32 PM**

Isn't that the same (former?) LMS-5400 basket from TC-sounds?

Wasn't Steve Meade from Topeka, KS?

**NDMstang65** · **08-08-09, 11:06 AM**

Yes...that ornamental frame patent on that basket was formerly owned by TC (Thilo) who sold stuff at his bankruptcy auction...we purchased the patent.

Meade is in California..

**looneybomber** · **08-08-09, 12:48 PM**

I do like that basket. Help me out, but does it have a spider landing big enough for you to use a 12" spider? I was thinking the old LMS-5400 used a 12" spider which helped reduce it's 2nd and 4th order harmonics.

What size spider will you guys be using?

Quote:

NDMstang65 wrote:

Meade is in California..

For some reason I was thinking he originated from Topeka, KS?

**NDMstang65** · **08-08-09, 01:03 PM**

No it's a 10" landing...

There is no need for having a spider that large in diameter, but Scott and I come from a very different train of thought...

**looneybomber** · **08-09-09, 09:25 AM**

It depends on the VC size. The smaller the coil, the smaller the spider...within reason of course

So what are your thoughts on 8" vs 10" spiders?

What made you choose progressive over linear spiders?
And you're using the built in 10" landing, or have you added a spacer to reduce the size down to 8"?

What cone material and shape/profile are you using? Dust cap?

And lastly, yet maybe most importantly, is there a price yet?

**NDMstang65** · **08-09-09, 09:58 AM**

Progressives that we use are more linear than a linear spider with respect to a kms curve...

8" spiders work better on a 3" coil, to an extent.

Curvalinear cone body that is the same as we use on all of our 18" subs except the BTL's. Dustcap will probably be paper or a hard abs plastic...

No clue on price, I just stuck it together the other day when I posted the picture.

**ccdoggy** · **08-09-09, 04:40 PM**

Personally I think that looks like a great sub to say the least.

how is the surface area compared to other 18"s. to me it just looks like it might have a little more which would be great. I am a big fan of high excursion big movement subs, if anything they look cool when you get them moving. Lower the tuning the better as i am sure you know we like our subsonics, and so some more drivers based around this concept would be more then welcome. especially when asking for input on the development from the community.

I have a Q 15" in a EBS and it sounds phenomenal compared to everything else i listen to and am anxious to just have more options when i finally get out of college of what i can build.

**weverb** · **08-10-09, 12:48 PM**

How do you think it would compare to your IB318 if you modified it for IB use? I already have two (IB318's) of them and I am thinking of ordering two more.

**Ricci** · **08-10-09, 02:28 PM**

Quote:

NDMstang65 wrote:

Yes...that ornamental frame patent on that basket was formerly owned by TC (Thilo) who sold stuff at his bankruptcy auction...we purchased the patent...

So is the motor on this guy screw on with a locking screw? That'd be cool. I really like that feature, especially when it comes to shipping. Being able to easily remove the heavy motor from the frame and softparts for shipping saves headaches. I don't think my LMS would've made it to me unscathed otherwise. UPS tried though...

Quote:

NDMstang65 wrote:

No it's a 10" landing...

There is no need for having a spider that large in diameter, but Scott and I come from a very different train of thought...

Unless you are using a 4" or larger vc and want a large excursion.

I have a few other questions. There is a lot of coil overhang above the top plate which is a fairly thick top plate too. Is this a standard overhung motor geometry? If so that must be a long vc wind like 3.5" or something (assuming it's a nominal 3" OD and there doesn't seem to be enough top plate for a split coil + too much overhang). Is this the case? Can you give a rough BL rating for the motor?

**Fi Audio** · **08-13-09, 03:07 PM**

Just on with plain ol' screws. The screw on motor or side screws to the basket for the motor removal or recones is covered under other patents that I wasnt interested in when they were up for auction.

With the size of the ring we have in there we could use a little longer than normal coil. The top plate has a bump up into the basket as well (which from the angle is just barely covered by the basket). So the coil you are seeing is really all that is sticking out. I believe its right at 1.000" overhang. FEA shows things to be 33mm of Xmag. Nothing earth shattering, but plenty for 95% of applications out there. Surround limits out at 3.450" and suspension is good for 32mm Xmech and 3.150 p-p.
With the magnet sizing we fit a .35" thick aluminum shorting ring between motor bump and all the way up magnets. If it doesnt linearize inductance as much as I would like, Ill play with a full copper sleeve on the pole as well or a pole cap/ring. But... Im more a fan of linearizing inductance swings than reducing it as much as possible in one direction (like many things I have measured do and I can only imagine its because their measuring systems sum inductance in both directions showing a net inductance loss, albeit at the expense of higher distortion due to the massive shifts in inductance p-p).

Nick misspoke earlier regarding IB applications. Too much motor for anything realistic for IB. While I could detune it to do IB, it would be a massive waste of motor force in doing so. Bang for buck it seems the IB3 and IB2 are the way to go.

10" spiders are a necessity with a 4" coil. On a 3" coil, they work but have some inherent stability issues with all units I have used. I have a solid FEAd design for one that seems to solve most of the problems that I have seen, but I will need to tool new surrounds to match its ability as well. A solid 8X3 spider works well to 3"p-p of excursion. There is a definite ratio of material and geometry with respect to spider diam and VC size that I like to stick with for longevity. Of course this is only in regards to standard spiders and nothing exotic like we have used for industrial applications. All bets are off there.

15" and 18" good enough? Or is there an interest for a 12" as well?

Shipping wise, Im not concerned. They dont weight that much and with them foamed and crated we wont have any shipping issues. We have only had 1 issue with a 70+lb sub in the past 2 years and that was due to a forklift skewering the side of the box and crate... not going to try and protect them from that

Thanks,
Scott

**onebadmonte** · **08-13-09, 03:38 PM**

Thanks for the info. Your insight on how you go about designing these is a great treat. Do you have any recommendations on box size?

**weverb** · **08-13-09, 03:49 PM**

Quote:

Fi Audio wrote:

Nick misspoke earlier regarding IB applications. Too much motor for anything realistic for IB. While I could detune it to do IB, it would be a massive waste of motor force in doing so. Bang for buck it seems the IB3 and IB2 are the way to go.

Ok. I just ordered two more IB318's today any way. I figured they were going to be hard to beat "bang for the buck" wise.

**Ricci** · **08-14-09, 10:33 AM**

Thanks for the answers and technical insight Scott. Sounds purdy good...

**SQCherokee** · **08-15-09, 06:22 PM**

I know this is a home theater specific sub which will make design work abit easier. However, would you say that they compare to the line up of car subs?

More output like the BTL's, yet more sq oriented like the Q's but with abit more output than the Q would be capable of?

**robseyes** · **08-28-09, 01:09 AM**

These sound like they will be awesome! I would love to see a 15 with reasonable inductance (2 or under) that could have enough BL to work in medium to smaller enclosures.

........I know Iknow it's all about tradeoffs.

Any idea when these will be available?

**ccdoggy** · **08-29-09, 12:12 AM**

I would be interested in a 12" version for my computer system. something a bit smaller yet still way overkill which i am known for. any more progression on if this will happen or not? options on it or none?

**Owen Bartley** · **08-31-09, 04:04 PM**

Very cool looking driver, and the design info is really interesting. Speakers always seem like a relatively simple contraption, until someone who knows a lot about them starts to explain things.

So this is targeted toward large, ported enclosures? Any possibility for small sealed?

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