2xAutoTuba results from USAC / DB Drag Race

[CafSentryGnome]

so would putting 2 MCM 8s in one AT wired in parallel make it a 4 ohm load or 6 ohm?

[jcmbowman]

6 ohms.

the +4 ohms added for the horn path is added after you calculate the driver load.

[crockettnj]

There is a huge weight, cost, and displacement difference between the 8" mcm and the 10" HLc.

even with two of the little 8's you are still less mass and money than one 10Hlc. considering the 10" Hlc can take a gagillion megawatts, is the Exursion limited output of two mcm's even yet equal to one 10Hlc? If you are considering multiples , as some have for small prosound gigs, can the 8" mcm's hang with the HLc's at a 2:1 comparative ratio?

Also, since they are discontinuing and selling out the big 10" Hl, might one expect that a neo-equivalent version is on the horizon?

[Bill Fitzmaurice]

Also, since they are discontinuing and selling out the big 10" Hl, might one expect that a neo-equivalent version is on the horizon?

Not likely. The HL10c shares its motor and frame with a number of other hi-fi and auto sound drivers, and Eminence is moving out of that market, so the frame and all those drivers that use it are history. A 3010LF may be in the works, but if so it's probably a year and a half away.

[bgavin]

At NAMM, I pointedly asked Jerry McNutt about why no 3010LF, and he told me there is huge pushback against 10" neos.
Evidently some other OEM released a turd in the market place, and it really soured the buying public on 10" neos.
Unwashed remains unwashed, unfortunately.

I'd be all over a 3010LF... the possibilities of it replacing the BP102 are wonderful.

[AntonZ]

At NAMM, I pointedly asked Jerry McNutt about why no 3010LF, and he told me there is huge pushback against 10" neos.
Evidently some other OEM released a turd in the market place, and it really soured the buying public on 10" neos.
Unwashed remains unwashed, unfortunately.

Weird, the DL2-2510 is no slouch and I can imagine it being quite a succesful driver.

I'd be all over a 3010LF... the possibilities of it replacing the BP102 are wonderful.

+1
I see featherweight slim T39s on the horizon. If that day will ever come, that is.

[bgavin]

I used DaveK's 15" wide T39 with BP102 installed last weekend.
Damn near featherweight, even with 1/2" Arauco and BP102. Truly amazing.

He figures 3/8" BB is the same weight as 1/2" Arauco for a T39.
My 3/8" BB weighs 42.1 pounds per cubic foot, measured.
The is the exact thickness * 60 * 60 inches / 1728, measured on the beam balance scale.
I have three sheets of 1/2" Arauco in my trailer, but have not measured them.
Their stated weight is 33.6 pounds per cubic foot.

I'm running out my stock of 1/2" BB with the T48 project, and replacing it with 3/8" BB.
My OT212s, etc, are 3/8" and I'm entirely satisfied with the construction quality.

[dmusgrave]

In the video he said it sounded better with the windows up. That would make sense since the woofers are only 6.5" . If they were 10 or 12's I think they would sound better if the windows were rolled down. Just my thoughts, I dont know the physics of it but I am sure Sydney could tell us or Bill of corse.

Cabin gain. Without it those stupidly high measured SPL levels don't exist, and as soon as you roll the windows down it's gone.
The only thing about that video that should come as a surprise is how little the so-called 'professional' in the passenger seat knows about the physics of sound. True, he's probably working from a script, but what's unfortunate is that the vast majority of auto-sound pros have a knowledge base that only extends to the advertising copy of the products they sell, so the script is founded in reality. But to be fair the same applies to the guys who man the sales floor at G-C and the like, let alone Best Buy.

Actually you usually gain a bit on the TL running "outlaw..." i.e. with the door open or a window down.

[Radian]

+1

The gains are however dependent upon the frequencies played, and most specifically, what type of vehicle (natural frequencies of cabin). Windows can change that tuning to a certain extent.

Example: Honda Accord 4DR with an AT windows Open Vs. Closed

Rear Passenger window down @ 25 Hz = +6 dB (you could feel this difference)

Driver side window down @ 31 Hz = +3 bB

Above 31, very little change with any window(s) up or down.

[Bill Fitzmaurice]

+1

The gains are however dependent upon the frequencies played, and most specifically, what type of vehicle (natural frequencies of cabin). Windows can change that tuning to a certain extent.

Example: Honda Accord 4DR with an AT windows Open Vs. Closed

Rear Passenger window down @ 25 Hz = +6 dB (you could feel this difference)

Driver side window down @ 31 Hz = +3 bB

Above 31, very little change with any window(s) up or down.

How much cabin gain you get depends very much on how tight the car is, and how inflexible the body panels and window frames are. The real screwballs fill the doors and panels with concrete, and replace the windows with steel plate so they can get another 10dB. All very pointless, but to each their own.

[Steve Regier]

Here is what I use to go to war with the natives!

[AntonZ]

Here is what I use to go to war with the natives!

Have some mercy on the natives in your area

[ewetho]

Ahh Steve!! Sheash!

Wait till you have 3 T60 and you can play those out the side door. LOL

[Mikey]

so would putting 2 MCM 8s in one AT wired in parallel make it a 4 ohm load or 6 ohm?

6 ohms ... the +4 ohms added for the horn path is added after you calculate the driver load.

Multiple driver cabs are calculated the same as multiple cabs. The total would be 4 ohms, nominal. However, with the relatively little power needed by ATs, it's pretty much a moot point normally, since damn near any typical car sub amp can deliver more than enough power to them, regardless of whether it's a 6 ohm or 4 ohm load. If you're dealing with teenie amps like the ones previously mentioned in this thread, it's more of an issue, though.