WITHDRAWN

[Skezza]

I have a very old peavey 2 x 10 bass cab designed to be used with the old 1 x 15 combos

The cab is a sealed enclosure not ported anywhere.

Does this matter what difference will there be as oppose toa ported cab like my 1 x 10 swr

skez

Edited January 9, 2012 by Skezza

[warwickhunt]

A sealed cab will be less efficient but that's about all. It will sound different to a ported 2x10 cab but no different to any two differing bands regardless of porting.

[sixdegrees]

I've always gone with the general rule of ported for SS/Hybrid heads, and sealed cabs for valve heads.

Sorry that doesn't answer the question.

[ShergoldSnickers]

Generally, with a sealed cab the bass starts to roll off earlier, but with a gentler slope, compared with a ported cab. The bass end of a ported cab will tend to give more output to just below it's port resonance frequency, after which the bass output rolls off quickly. Due to the way box sizes, speaker resonant frequencies and speaker efficiencies pan out, a ported design will usually give greater bass output, and with a more extended response. There will be exceptions to this for particular mixes of parameters, but generally it holds. Some will argue that s sealed cab will give more accurate bass, even if the level is down on that a ported cab would provide. The transient response of a ported cab is compromised through having to use the port resonance to get the extra output. Apparently.

[Bill Fitzmaurice]

[quote name='ShergoldSnickers' timestamp='1324744192' post='1477538']
The transient response of a ported cab is compromised through having to use the port resonance to get the extra output. Apparently.
[/quote]That's a common misconception, and isn't true, as transient response is mainly a midrange issue, while porting doesn't affect the mids. Some vented cabs sound good, some don't. The same applies to sealed. One can mess up with either topology.
The main reason to use a sealed cab or vented cab is the drivers contained within. Most drivers today are made with specs that work best with vented cabs. Most drivers from 40 years ago were not. Vented cab technology wasn't well understood prior to about 1970, and it took driver manufacturers about ten years after that to get up to speed.
[quote]I've always gone with the general rule of ported for SS/Hybrid heads, and sealed cabs for valve heads.[/quote]There's truth to that. The impedance characteristics of vented tends to be more friendly to SS output stages, that of sealed more friendly to tube output transformers.

[ShergoldSnickers]

[quote name='Bill Fitzmaurice' timestamp='1324748789' post='1477607']
That's a common misconception, and isn't true, as transient response is mainly a midrange issue, while porting doesn't affect the mids. Some vented cabs sound good, some don't. The same applies to sealed. One can mess up with either topology.
The main reason to use a sealed cab or vented cab is the drivers contained within. Most drivers today are made with specs that work best with vented cabs. Most drivers from 40 years ago were not. Vented cab technology wasn't well understood prior to about 1970, and it took driver manufacturers about ten years after that to get up to speed.
[/quote]
Yes, I found conflicting views on that and was wondering if we were back in that strange parallel world where 'larger drivers sound slow' etc. Fast transient response means a cliff-like rise in amplitude, something that can only be accomplished with a small and light driver - a mid or treble driver. Yes, it makes sense.

[Bill Fitzmaurice]

[quote name='ShergoldSnickers' timestamp='1324750113' post='1477627']
Yes, I found conflicting views on that and was wondering if we were back in that strange parallel world where 'larger drivers sound slow' etc. Fast transient response means a cliff-like rise in amplitude, something that can only be accomplished with a small and light driver - a mid or treble driver. Yes, it makes sense.
[/quote]A number of factors influence transient response. Best results tend to come with low Mms high Qts low Le drivers, which tends to be common with drivers that work best in sealed alignments. Drivers optimized for vented tend to have higher Mms lower Qts and higher Le, so they may not have as good a transient response. But it's the driver that makes the difference, not the box you put it in. And if you want the lowest possible Mms along with the lowest possible Le you get it with a driver that has a smaller cone and smaller voice coil. In other words, a midrange driver.