New Mach 5 Audio IXL info - Page 5

It looks OK for a 2.83V sensitivity (2.5W/3.2R), or 88.8dB for 1W.

I am in for 16

Give your video camera a break and start paying attention.

I noticed today on the website the price has been set at $420. I'm tempted to upgrade my twin Atlas 15's.

Do you live at a hydroelectric dam or something?

Actually, efficiency increases 3 dB with every doubling in number of drivers, assuming box volume increases proportionately.

lol I have been takig it easy on the camera and the system for months now, so those few occasions I pick it back up and turn it back up I do get a little tunnel visoin 1Hz for 1minute! jk jk!

I didnt invest any time in the port, in fact I did all my plots without touching port till i decided I should get a vent velocity and changed 4" to 8" and went ...oh ****! Notch filter if there is a bad resonance? Do elbows and bends alter that? Fine! Slot port!

No to the notch filter. The resonance will still be there. Slot port, maybe. I don't really know much about those. This is where PR's shine. No crummy port resonance to deal with, ever.

Oh yeah, huh... it's not the driver creating the port resonance with the driver making it at that frrequency... helmhertz? Got it

PRs have resonance don't they? Or is that just at the tuning?

A passive radiator is pretty much a sub driver without the voicecoil. No power. They do keep a full suspension system (surround and spider) so the PR will have a Fs value. As part of a subwoofer 'system' it will have a definite resonant frequency or Fb just like a vented system.

Thanks for that correction/clarification.

The helmholtz resonance of either ports or PRs is not a problem.

The problem is the quarter wave resonance of ports and transmission lines.

Now with TLs you actually use the first QW resonance to augment the slope in driver response, and stuff the whole line with polyfill adequately to cut higher harmonics until they're down to +/- 1db at which point we can effectively call them inaudible. The tradeoff is a loss in line efficiency but the sloping response tends to work decently enough in rooms. For main speakers that means any line harmonic are NOT audible!

Not many people stuff their ports like that, especially not a for a sub optimized to only operate with a low pass filter at 80hz or 100hz for max output. The port is only there to be a pressure loaded mass of air, and any QW behaviour is just a side effect. In that sense, using a mass of something else that won't have such a side effect does make sense. I'm sure there's other small resonances higher up in frequency (IE 400hz?) but i'm not sure they'll be excited because Passive Radiators barely move so high up in frequency.

Now one might say a 140hz vent QW resonance (of a 48" long tube) is a problem. But an 80hz 4th order low pass is pretty significant imo. Here's an example of a speaker with a 110hz vent resonance:

http://forums.audioholics.com/forums...4&postcount=58

And that guy claims he doesn't hear any vent resonance.

FWIW, I had a pair of MJ-18's (4ohm SVC, rated for 600e RMS) in 3.25cf each off an Earthquake PHD-3 (2kw RMS), great wiring but only the stock 650cca lead acid battery, for over 5 months no problem.

My buddy had a pair of his MJ-18's in 1.8cf each off an Orion 2500d (2500w RMS), even better wiring but same size stock battery, for over a year, and no issues.

I wouldn't worry about putting more than 1200w into the Pi18... but finding that kinda power in car audio @ 4ohms isn't the easiest/cheapest thing to do.

It's a good thing they're not 4ohm DVC... I'd definitely run an ep2500 per coil

I asked about the DVC option and he said it would cost more but I never found out how much more. And being tight on budget I didn't know if I could float the added price. But this is also on the 21". I am sure it can be done to the 18 as well.

I must be slow today, but what is the point of DVC for a home sub?

I'm also still surprised that so few people understand the difference between a power rating, amp power and the actual power applied to a driver under real world signal conditions.

I agree, really don't know why you need a DVC. The new blueprints are going to be a SVC 4 ohm.

I would have used a DVC to aid me in wiring configurations. SO I could use a pair for now and use four later with the LG Fp14000 clone. I was thinking of having dual 8 ohms for mine.

I'd very much prefer dual 4ohm or something like that so I can use these dual-opposed with a 4ohm nominal load. That would be nice.

ya well my deck was set to 22 out of 35 and the gain was like 4/5ths the way up!

When you get them up and running, PM me. I'd love to hear 'em and you're 10 minutes away

No logo, good.

Shorting ring in the motor, good.

No spec even given for inductance, provisionally bad (it's reasonable to assume that when something important isn't provided, it's not provided for a reason).

DS-21 - shorting rings are used in the motor. Wish they listed Le though. Glad I can get them without the logo. Now if I can just get them dual 4ohm or single 8ohm.


In listed features

What about the tall rubber surround? Is that option available?

I believe that was an option for some of those that ordered early and had custom work done. Guess it was an option to get the tall surround. I myself would like to get these with the tall surround. Though having those may change the T/S numbers to something the Mach5 guys didn't want.

You're quite right. Dunno how I missed that. Original post edited.

Um.. what?

What advantage would there be to not using any shorting rings?

Haha. Hey, DS-21. You might need to re-edit the post again. You saying that not having a shorting ring may read that as out of character. You wouldn't ever say that.