sealed cab vs ported

Its tough to say. I think Mesa/Boogie has always ported their bass cabs, and they sound amazing with their tube heads. I use a Mesa Bass 400 and a Powerhouse 4x10 and some other good cabs, but the Powerhouse beats them all out.

 

I think that there are many ported cabs that sound good with tube heads, and most sealed cabs that I've heard sound good with either. However, I think that in general, ported goes better with SS. But I think sealed goes well with either, as long as its a good sealed cab and not some (modern) Ampeg 810.

 

Nope, not just you. Tube amps have very low damping when compared to a s/s head. Sealed cabinets offer more "natural" damping then ported cabs so you get a "tighter" sounding cabinet with sealed.

Damping is the amps ability to control the speaker. The more damping, the better defined the bass.

 

True, from a theoretical standpoint, but extensive testing has shown that very high damping factors don't actually translate into better sounding amps. In theory ported cabs will almost always work better than sealed down to 40Hz or so, but only when properly engineered and constructed. When done right they sound great, when not done right their flaws are much more obvious than with sealed.

 

On my bench, the ported cab is always louder, usually +3dB.

I took some measurements of a driver in a cab that provided SBB4 tuning. Blocking the ports made the same cabinet volume a D2 sealed alignment. If you pay attention to my spread sheet, you will see this occurs more often than not... one could draw a correlation between D2 as the sealed equivalent of SBB4. Both known to offer the tightest bass response.

I plotted a spread sheet of open/blocked ports, and found the open ports to be louder. Just like they are supposed to be. I don't have the equipment to take impulse measurements, so cannot comment on one cabinet having tighter response than the other.

 

I think most of the time the perception of tight response is a midrange issue. A sloppy midrange from insufficent damping inside a ported box will give the impression of flabby bass. Look at the innards of some ultra-high end ported hi-fi boxes and you'll see part of what ten grand will get you is six inches of foam.

 

It's just you, but then it might be just me

I've always prefered the "tone" of ported cabinets. I couldn't care less about formulas and bench tests personally... I use "my ears" to hear what works best for "my tone".

Sealed cabinets sound choked to my ears... specially with an all tube rig. They fight against the dynamics of playing through a high powered tube head.

 

Can you elaborate a little more on what you mean/are hearing? That POV is interesting.

 

Simple, playing through a sealed cabinet at high volumes I can sense/hear the internal pressure resisting the cone... it's not bad, it's actually a good thing if it's part of your tone. I prefer the tones I can get from a driver that has free movement with in it's own physical limitations.

Is this imagined.... maybe, but it's a real observation and conclusion I've come to over the years for myself and my tone. Cabs that I've gave the nod to always have been ported and the ones I've used that gave me that choked feel have always been sealed.

 

Interesting stuff.

OT: Let me know if you're playing anywhere during the summer. I'm taking a trip to NY to see nino and roger and i'd like to stop in your area to hear you play. (and see your sick pair of bennie's )

 

Just wondering, is there somewhere you can get this foam for less than 10 grand?

I think that is not a fair comparison. Different box sizes and drivers are generally used in a sealed box design. Just taking a ported cab and blocking a port tells you nothing about ported vs sealed cabs responses. Any more than taking a sealed box and cutting random sized ports in it would be a fair test of capabilities of ported boxes.

Randy

 

@James Hart,

What sealed cabs have you played? If you ever get the chance, try a Berg NV215. It's amazing with tubes & just as nice with s/s, best sealed I've ever played/own/use. I still love my Bag End 2x10(rear ported) with tube & s/s. For pants flapping lows, it's my PV2x15 & Mesa Diesel 1x18 with Kern/Crown power. My Accugroove 2x10 sounded great with the Crown but not nearly as nice as the Berg or the Bag End with an all tube amp. Ported gives you more lows with the right amp(dampening wise) but sealed is more controlled & as mentioned, less open but never muddies up & stays tight way down low(driver permitting), just not as much pants flapping(escaping pressure etc.). Neither cab is superior, comes down to application & what's in front of it...

~S~

PS: I had a NV610 & would love to try a NV425, don't care for Ampeg 8x10's...

 

That's true, but on the other hand it will tell you how a particular driver in a particular box size reacts to being either sealed or vented. What is pertinent is that most of the drivers used in bass cabs are optimize to work in vented alignments, and those that are capable of giving equivalent performance when either sealed or vented require a far larger cabinet when sealed. Within the normal operating range of woofers for electric bass with f3s between 40 Hz and 90Hz and box sizes of 1 to 4 cu ft per driver I'm not aware of any drivers that operate anywhere near as well in a sealed cab as they do in a vented.

 

That and the whole reason people use ported/vented cabs is that they are inherently more efficient. The back wave instead of opposing cone movement and reducing output gets thrown out front to reinforce the front wave at the low end. I just didn't see what the point of that post was besides stating the obvious... and an unfair comparison at that. As bad as doing the opposite, take a sealed cab, with drivers designed for that app, cab volume appropriate for that application, and cut ports in it to see if its better or worse. Of course it'll be worse, just like covering up the port in a cab designed to be ported. Sort of like an experiment to see if a room is really brighter with the lights on...

Randy

Randy

 

+1 Datz right.

 

I do hear what you are saying, and some of the sealed cabs that I played through sounded that way. But, a vintage SVT rig at full volume is very dynamic - though admittedly, it doesn't sound quite "right" unless you push it really hard.

But, I will add that my NV215 sounds killer (very tight, quick and dynamic, with deep, yet balanced, tone) at quiet and loud volumes, and it just rules with a 400w tube head!

 

I have been playing bass for years as you seem to of also. What is "right". I just sold my 3 month old svt cl because this "right" sound is distortion. Others call it growl. I just ordered the new svt 6 pro...1100 mosfet watts with four preamp tubes and two user voltage controled driver tubes. Not to mention the parametric tone adjustment ability.

My prefered tone is HUGE CLEAN bottom end and nippy highs. No big "smilley face"...just a small one and you need CURRENT for this....especialy pushing 810e cab.

 

Good points. When I say "right", I mean "right for what I expect from a vintage SVT", which is a healthy dose of growl/grind. I love this tone, but I certainly would not want that to be my only tone, and so I've delved into additional tube amps (many of which are, IME/IMHO, much more tonally flexible than the SVT).

For your tone, have you tried Trace Elliot tube amps?

Tom.

 

Tom, in the last 6-8 months, I have bought three major amp purchases...I have one foot out the door, the other on an old 70's nylon guitar strap and the wife pushing me hard!