Music Man HD-130 and Ampeg cab review

[Dave W]

Just think - with the right stuffing, you could have had a Sealey Posturepedic Cab!

Or better yet, for those of us of a certain age, a Serta Perfect Sleeper with Joey Heatherton.

[drbassman]

That's how you market mattresses!

[Granny Gremlin]

Not according to speaker "nerds.". Kinda reminds me of poly vs. nitro debates.  Either way, the cab kicks butt now.  My amp just has to work. 

No, he's right, polyester pillow stuffing is almost the same thing as Accoustastuff (Allegedly; I don't use either).

If only one cab is making the noise, maybe it's not the amp that's the issue.  Try playing each speaker solo.  If you only get the static from the EV, it could be a light voicecoil rub - that can sound a bit like static sometimes. 

[drbassman]

I tested the amp with both cabs together and individually and I get the static in all situations.  I suspect that this static was what caused me first to question the speakers when I set the rig up for a trial run at practice.  I thought it was ambient rattling and speaker farting, but now I think it was amp malfunction that is random, not continuous and I couldn't discern the problem in the cafe setting.

I'm calling the amp guy today.

[drbassman]

Got the amp from the shop.  Got the caps replaced, pots cleaned and everything checked out.  The static I was hearing was due to a couple really dirty pots.  Duh, I should have figure that out.  The new Ruby tubes are fine.  It sounds great now through the 2 MM cabs.  The cabs sound better as well with the damping material.  The low end on them is improved, but not as deep to my ears as my other two 15" cabs, the Ampeg and the Mesa. 

I'm beginning to think the modern design and new speakers of the Mesa and Ampeg are simply better than the older style of the shallow box/bottom vent of the MMs.  The MMs are definitely warmer and stronger now that things have been fixed and make me think of the good old days of my bass playing youth in the 1960's.  They do however lack the depth of bass that the newer cabs have.  Other then that, they sound good and can handle a lot of volume now.  I'm taking them to practice and set them next to the Mesa/Ampeg cabs and compare them directly while playing at volume.  We'll see the difference then and confirm whether or not my brain is fooling me.

[dadagoboi]

Exactly why I don't like ported/vented cabinets.  Extended range is completely overrated, I hate the 'modern' bass sound.  Give me a good sealed infinite baffle cabinet any day, way punchier with better transient response than any ported design.  As far as I'm concerned a first generation SVT cabinet or three with a good amp apiece can't be beat live.  And a B-15 in a studio will get you any sound you need from clean to supersaturated tube distortion.  Tweeters and subs need not apply.

[Granny Gremlin]

Sealed (aka acoustic suspension) has, by defenition, poor transient response.... then again, so do bass reflex (not sure off hand which is worse, but I'm with you as regards that 'modern bass sound' in that I'm not a fan of bass reflex cabs in general, though they can be done well - see vintage Tannoy studio monitors).

The best transient response comes from open back (sacrificing bass response unless you  put it in a very large baffle) and transmission lines (which require a box that is even bigger than a sealed, assuming the same drive unit).  This is because the speaker is operating in a box that mimics "free air" (vs the pressurized nature of a sealed or even ported, aka strategically leaky sealed box).  This minimizes the amount of force required to move the cone so it can react faster whereas sealed cabs hold the speaker back due to internal air pressure (the trade off here is that the speaker can handle a bit more power due to this added resistence to movement; it becomes harder to push the cone/voice coil to the extremes of travel).

Also, ported cabs (using the same drive unit) do not have an extended range vs sealed - the opposite is true.  Ported cabs just have a response that is flatter lower, to the point of the port tuning at which  the response falls off a cliff. A sealed cab will start to roll off earlier, but much more gradually providing you with lower bass frequencies, but not as much of them.  This tends to sound more natural to the ear vs a ported which can be boomy or hyped in the lower midrange/upper bass (giving the impression of more low bass, without actually having more).

Further, some designers attempt to make this psychoacoustic trick even more effective (usually with smaller speakers or ones with relatively high resonant frequencies) set the port tuning so as to produce a bump in the response just before the response rolls off.  I find this sort of cabinet most displeasing soundwise, but I dunno if any instrument cabs are made this way or not.

[Rob]

I'm with Carlo Granny.
What the chart misses is the "texture" or feel of the sound.(how's that for a troll)
Now compare Tubas. . .  say fibreglass to brass, to nickel plated same notes different texture and overnotes.

[Granny Gremlin]

That's the thing - I agree with Carlo as well,  it was just the reasons for that preference that I was speaking to.

Anyway, in all that carry on I forgot to mention to Dr B:  make sure you run those RH cabs (at least the bottom one if you stack them) with the port on the floor (vs to the side as I've seen in some of your pics before... or someone's pics on this board anyway).  It effectively extends the horn (think 60's era  hifi corner horn, e.g Klipsch) and therefore increases bass response.

[Dave W]

...

Actually, that diagram is a little unfair (i am biased against ported cabs  ) but I'm too lazy to redraw it and it still demonstrates the basic idea well (if not the relative magnitude of the differences).

It's more than "a little unfair." Obviously you'd rather severely misrepresent the differences than to draw it accurately.

[drbassman]

My ear is the only measure I need!  It's not an oscilloscope, but it sends the data to my brain just the same.

[Rob]

My ear is the only measure I need!  It's not an oscilloscope, but it sends the data to my brain just the same.

[Granny Gremlin]

It's more than "a little unfair." Obviously you'd rather severely misrepresent the differences than to draw it accurately.

I was honest about it.  And you're just insulting.  Do better in half a minute in MS Paint. 

It DOES illustrate the principle (not the magnitude, as stated).  I wasn't trying to convince anyone which is better (because, for the 3rd time, I agreed with Carlo on that preference.  The point in all that was to clarify that ported cabs don't have extended range, though it might sound like it sometimes, and that sealed don't have particularly good transient response).  I think the TR thing is especially useful to know, the other thing is really mostly down to preference.

Would you prefer I remove it? Cause I would if you really think it's "severe" despite any indication of scale and the blatant disclaimer to that effect.  Just thought it would help to visualize what I was saying.

[Dave W]

I would prefer that you do it accurately in the future if you're going to do it at all.

[drbassman]

Wouldn't it be different for every cabinet tested anyway?  I would think there's no one "correct" graph.  Each graph would be different when you're measuring an actual cabinets.  I think I understand that.