My test: B2 Audio M1s... + CT7k

[TaylorFade]

Last one and I'm wrapping this shit up. This will also be a little bit more of a review than a straight heads up comparison- although... the comparison is inevitable.

Here we have the B2 Audio M1s. I know their model names are pretty confusing, but this is their 6-7k amp. Designed in Denmark and Korean made. We have a little experience with them already since Alan used them to win a championship in trunk a few years ago, but never did a full write up.

If you talk to anyone from B2... they LOVE this amp. It's their "street beast". And they designate it a "street voltage" amplifier. Meaning... it's optimized for 12v systems and daily type impedances.

B2 Audio M1s mkii

Rated - 5,500@1 12v. 7,100@1 14.4v

Price: $1,560 (B2AudioStore.com)

I'm told that this particular amp is an early version of the second generation M1s that was sold in Europe. The newest generation has some tweaks to the power supply and some other top secret shit. So keep in mind that if you bought a new one, it'd be different than this one. And probably stronger.

I completely spaced on the comparison pic and I'd already boxed the CT back up so hopefully this will give you an idea of its size. Next to the AB and then a reminder of the group shot. If it helps, B2 says it's 29" long.

Triple inputs. I know you guys loooove the triples. So, here you go.

Solid metal pots. And frequency adjustable bass boost. If you're going to have bass boost, at least make it adjustable. You'll also notice "slave1" and "slave2". Yes... you can strap (3) amps with B2. Pretty awesome.

Dem guts.

On to the testing...

Bit of a break from the other testing, these will be done on my spiffy new mobile test bench. Which is just a cart with batts, power supply and HU. (3) NSB100's + 100A/13.8v power supply. Tryna be like Stevie, yo.

Unloaded. Yeah... that's a lot of voltage for a 6k.

First loaded test is 2.5 ohms resistive.

That's 3,240w @ 2.5ohms and 12.3v. (rated 3,200 @ 2ohms & 12v)

1 ohm resistive.

5,950w @ 1ohm and 11.5v. (rated 5,500 @ 1ohm & 12v.)

So, it passes "certification" with flying colors. Which very few do since, in my tests, I let the voltage settle out. As you can see in the pics, DC amperage draw was also measured but I hesitate to even give you guys the numbers since some may take them out of context. But since it's right there in the pics anyway, I'll just tell you... 62% efficient @ 2.5ohms and 12.3v and an ugly 51% efficient @ 1ohm and 11.5v. But listen... this is what happens when your voltage gets that low. Efficiency suffers when you ain't got the juice, yo. Couple this efficiency loss with the losses of running low impedances and it could get ugly in a hurry. But anyway, this is more of a "this is what happens at 11v" type thing than a dig on the M1s. Given the rock solid 14v the other amps got and there's no doubt the efficiency would be comparable.

Ok, I know y'all just want to see the clamps so I'll get to it.

We tested the CT7k first to establish a baseline score. The higher impedance test is a "daily" type situation. Meaning... 1 ohm nominal on a daily tuned box. The torture test was a burp box with a single 12". Sorry... no pics of the scores. You'll just have to take my word for it.

CT7k. 1 ohm nominal rising to 3 ohms drop to 13v- 2,450w. 151.3db

B2 M1s. 1 ohm nominal rising to 3.3 ohms drop to 12.6v- 2,600w. 152.2db.

Wha, wha, whaaaa? The B2 was louder? Yes. More on that later.

Next up is the torturous burp situation. The nominal load isn't so bad. It's the reactive that is a monster. This box is .35 nominal but it only rises to .6-.7.

CT7k. .35 nominal rising to .7 drop to 11.5v- 7,500w. 151.0db.

This f'n thing. It just won't quit. You almost can't make it NOT make 7k. Sheesh. 7.5k @ 11.5v. SMH.

B2 M1s. .35 nominal rising to .7 drop to 13.1v.... protect. Protect. Protect. Protect.... you get the idea. Ol' girl did NOT like this reactive load. At all. Best we could manage out of her before protecting was 4,400w and 149.7db.

I can't make any excuses for the B2 here other than it just isn't "made" to run this low. Not that the CT is either though. I spoke with someone important about the results and he was honestly surprised that it even made noise down there. Lol. On a positive note... it's got great protection circuitry.

The power to score ratio from the burp box isn't surprising (to me). 7k did 51, 4.4k did 49.7. I already knew this box topped out at ~ 6k. I've put 10k to it before and only gained a few tenths over 7k so that's why the scores are pretty close even though the power is much different. It happens. Not that +/- 1.3db is all that close in a burp situation, but you get the idea.

Now what is surprising are the "daily" scores. There's no 2 ways around it... the B2 was louder. And by a good bit. Why? Because SPL is retarded. That's why. Both amps were tested the same way. Both at their maximum clean gain and volume settings and coming out of pause full tilt. So why were the scores so different even though power was so close? Headroom. Plain and simple. The clamp results pictured are after everything settles out. A burp score is a burst. The B2 came out of the gate stronger and settled out to match the CT whereas the CT came out strong and stayed there. Caps? Power supply? Both? I can't say for sure, but this would tell me that the B2 has the ass to handle huge dynamic swings and stay clean. You can see it also makes a ton of voltage too so these higher loads are right in its wheelhouse.

Will you "hear" +1db on the street? No. Will you notice more dynamics in a daily setting? Probably. Will you notice +1.3db in the lanes? Without a doubt. These two amps may seem like they have different purposes, but they don't. You give a little to get a little here and there but at the end of the day, they're both beats on the street. They just go about it in different ways.

When I tested the B2 Zero.5 against the RD D5, I called them Bruce Lee and Chuck Norris. Well, these two are like Muhammad Ali and George Foreman. And that analogy is actually more apt than you think because these amps have a bit of a rivalry. The B2 being Ali- it has speed and finesse and will 'rope a' dope' your ass till you find yourself on the canvas. The CT is like Foreman in that if that big sum'bish gets ahold of you, it's all over with. Brute strength. Even if it is clumsy, you still want him on your side if shit hits the fan.

Personally, I wouldn't want to fight either of them... but I'd corner both.

[basshead7890]

Impressive

[Kyblack76]

Nice, i was going to pm you about this test, as me and Kenny (buddy) just slapped 2 of said B2 amps in his car on 2 level 6's.

We ALSO ran into the lowISH impedance protect issue, but, it made gobs of power anyway, at a slightly higher load.

Great write up as always man. Ill be chatting with you soon.

[vetkilr01]

Great write up as always...Love my 7k, my subs however do not.

[leonfowler]

i love it! good shit dude

[Loudman]

Nice testing. And a hell of an amp collection.