Question about Xmax

Clammy · #1 10-20-2011, 03:00 PM

All other specs being more or less equal, what would the result (tone, volume, etc...) of replacing a speaker with 2mm Xmax with a speaker with 5.2mm Xmax in the same cab?

Thanks.

Cheers!

will33 · #2 10-20-2011, 03:04 PM

Much more potential output in the lows before farting out.

That said, you can't change one spec without affecting the others and both drivers would not be suited for the same box.

Alex1984 · #3 10-20-2011, 03:13 PM

Assuming everything else is the same, it just raises the mechanical limit on the speaker, it'll have better "real power" handling capabilities. Of course, that's assuming your voice coils can take the heat. But if the head used isn't a high-powered head, there's probably no real advantage.

Clammy · #4 10-20-2011, 03:18 PM

Quote:

Originally Posted by will33

Much more potential output in the lows before farting out.

That said, you can't change one spec without affecting the others and both drivers would not be suited for the same box.

Thanks. Based on my very limited knowledge of T/S parameters, the cab is too large for the 2mm Xmax speaker, but the right size for the 5.2 mm Xmax speaker I'm considering as replacement. Would it's perceived volume be higher than the 2mm Xmax speaker it's replacing?

Thanks.

BurningSkies · #5 10-20-2011, 03:23 PM

Quote:

Originally Posted by Clammy

Thanks. Based on my very limited knowledge of T/S parameters, the cab is too large for the 2mm Xmax speaker, but the right size for the 5.2 mm Xmax speaker I'm considering as replacement. Would it's perceived volume be higher than the 2mm Xmax speaker it's replacing?

Thanks.

In the lows, yes, but beyond that it's hard to say. Remember a lot of perceived volume comes from the mids and from the overall frequency response curve of the speaker. Often times you get higher xmax at the expense of other features of a speaker.

Clammy · #6 10-20-2011, 03:41 PM

Quote:

Originally Posted by BurningSkies

In the lows, yes, but beyond that it's hard to say. Remember a lot of perceived volume comes from the mids and from the overall frequency response curve of the speaker. Often times you get higher xmax at the expense of other features of a speaker.

The frequency ranges are close (not sure about the actual curves, mind you) with the 2mm being about 1.5 higher at the top (6KHz, vs 4.5KHz for the 5.2 mm).

From what I've read on TB, when a speaker hits it's Xmax, it doesn't get any louder and just distorts more. I'm thinking that due to the cab being too large, and having my amp eq'ed with a lot of bass, that I'm probably doing that with the 2mm speakers (the cab is a 4x12). I do have a lot of grind in my sound by design, but I often think I'm hearing some ugly stuff coming from those 12s. Another thing that seems to happen, is that at the beginning of rehearsal, the sound coming from the cab is great, but after a few songs, it seems to... I don't know ... it's almost as if the volume gets lower, and more distorted. I play with custom fit ear plugs/filters, so I don't blame it on ear fatigue. Would pushing the speakers to their Xmax cause something like that?

The background here is: I bought an empty Marshall 4x12 bass cab years ago, didn't know sh*t about bass speakers (I know a little more than sh*t about them now, heheheh...

), and just bought a quad of Celestion 12" bass speakers and dropped them in. Now that I've learned a bit about speakers/cab designs (from doing a lot of reading on TB), I've determined that the cab is too large for the Celstions, and I want to replace them with Eminence Basslite 12s (S2012), which will be good for the internal volume of this cab.

Thanks.

Cheers!

billfitzmaurice · #7 10-20-2011, 03:42 PM

Quote:

Originally Posted by Clammy

All other specs being more or less equal, what would the result ... of replacing a speaker with 2mm Xmax with a speaker with 5.2mm Xmax in the same cab?

Roughly 7dB more output capability, all else being equal. But all else is seldom equal. You must software model the cab with both drivers and compare the driver manufacturer data sheet SPL charts to know exactly what the results will be.

BurningSkies · #8 10-20-2011, 03:45 PM

If you're using those Marshall heads, I'm guessing the 'mushiness' of your tone after a period of time is all about the amps rather than the speakers. That's definitely a characteristic of hot running tubes that used to drive me nuts.

Clammy · #9 10-20-2011, 03:59 PM

Quote:

Originally Posted by BurningSkies

If you're using those Marshall heads, I'm guessing the 'mushiness' of your tone after a period of time is all about the amps rather than the speakers. That's definitely a characteristic of hot running tubes that used to drive me nuts.

It's not the amps. It only happens when I'm plugged into that cab. If I use my Super Bass heads with any of my guitar 4x12s, that doesn't happen. Also, my VBA 400 is now my main bass amp, and it's barely at 2 on the volume dial (and it's a lot louder than the Super basses on 4 or 5, hehehe...), so those 8 6550s are not being pushed too hard. I don't think it's a tube issue. Also, it's not a "mushiness", it's a noticable drop in volume and a harshness to the overdrive/distortion character, and it's more noticeable with the VBA, which puts out a LOT more bottom end, than with the Super Basses.

Thanks.

Cheers!

will33 · #10 10-20-2011, 04:05 PM

Those heads in your profile also aren't that powerful. 2mm xmax is worthless for bass, you can do better than that but four basslites may be overkill, unless you plan on getting bigger amps one day. Could settle for xmax somewhere in between the 2 and go for more spl although the basslites ain't exactly quiet either. Finding such a thing in ceramic mag. would likely save a bit of $$ too. I assume weight isn't that high on the list when you're using a 412 and a tube amp.

Edit: never mind, didn't see the VBA. Your one cab getting quieter is then likey due to power compression, at least with the 400 watter.

Clammy · #11 10-20-2011, 04:07 PM

Quote:

Originally Posted by will33

Those heads in your profile also aren't that powerful. 2mm xmax is worthless for bass, you can do better than that but four basslites may be overkill, unless you plan on getting bigger amps one day. Could settle for xmax somewhere in between the 2 and go for more spl although the basslites ain't exactly quiet either. Finding such a thing in ceramic mag. would likely save a bit of $$ too. I assume weight isn't that high on the list when you're using a 412 and a tube amp.

Yeah, that's what I gethered (about the 2mm xmax being way too little). I'm guessing that I'm always pushing them to their max limit, and that, along with the cab being to large for them, is what's causing the volume drop/harsh distortion that I start to get after a few songs.

I'm actually using a VBA 400 now. The VBA puts out a lot more bottom end and is, of course, much louder, than the Super Basses.

Cheers!

DukeLeJeune · #12 10-20-2011, 08:04 PM

Quote:

Originally Posted by billfitzmaurice

Roughly 7dB more output capability, all else being equal...

My arithmetic says the same thing.

That's a huge difference. 7 dB is like going from 100 watts to 500 watts.

For anyone interested in the math, excursion-limited SPL goes up by 6 dB for every doubling of x-max (assuming cone area stays the same).