why no sEALed fEARfuls???

[rpsands]

You're setting up a false dichotomy between "response under 50hz" and "low mid punch" when the real comparison is "Response under 100hz" and "response over 100hz and distortion characteristics in the midrange."

The 3015LF absolutely crushes the 8x10 when you start looking at a tone profile where you have as much volume at 60hz as you have at 200hz (literally, a single 3015LF performs as well as two sealed 8x10s once you scoop all the stuff above 100hz down to flat).

I agree, its' an apples and oranges comparison. You won't find me saying why can't an 8x10 meet my needs - I know why it won't.


* However, when it comes to utility, I would argue that the 3015LF+Mid cabs are far, far more flexible. Getting an 8x10 to sound like a fEarful is infinitely harder than getting a fEarful to sound like an 8x10 (or at last close enough for gubmint work). Dialing in low mid punch is easy, dialing in low end to speakers that simply cannot produce it - not so much.

 

[Sundogue]

I do believe the only thing that matters is being right.

All this talk of sealed or ported, SVT or fEARFul, blah, blah, blah is nothing more than yet another excuse to prove one's point, and the point being how right we are.

Here's a question for y'all...

"Why no ported Ampeg 810 SVT's?"

Duh...

 

[DukeLeJeune]

One thing I've observed is that that tube amps typically interact more with the speakers they are driving than SS amps. This is because tube amps generally have higher output impedance. Ported cab impedance typically varies with frequency quite a bit more than sealed cab impedance. This can produce noticeable unevenness in response that's not detectable with a sealed cab. In a side by side comparison under these circumstances, I think many would consider the sealed cab to be smoother sounding.

Good point. I'd like to elaborate a little bit, at the extreme risk of going off-topic...

I would say that tube amps and solid state amps both interact with speakers, but they do so differently. Most speakers are designed for solid state amps, so it seems like the tube amp is the one that's interacting strangely, but arguably it interacts less with the speaker's impedance curve.

A low output impdance (high-damping-factor) solid state amp approximates a constant-voltage source, one result of which is that it puts out more power as the impedance of the load goes down, and less power as the impedance of the load goes up. Most tube amps have a considerably higher output impedance (lower damping factor) and more closely approximate a constant-power source, putting out about the same power into the load as the impedance swings up and down (within reason).

In the bass region we usually have impedance peaks, one peak with a sealed cab and two with a vented cab. Most cabs are designed to meet their target response with solid state amps, with the expectation that the cab will put out reduced power into those bass impedance peaks. So if such a cab is driven by a constant-power tube amp, the amp is putting out more power into the bass impedance peaks than the cab designer expected, and the result can be a nice warming up of the bass or a not-so-nice bloating of the bass, depending on the specifics.

One possible solution for the ported cab is to lower the tuning frequency, which will shift the region of bass boost due to amplifier output impedance interacting with speaker input impedance down lower in frequency. I use that technique in some of my home audio speakers to get deeper bass when used with a tube amp. The same thing could theoretically be done in a bass cab.

Across the rest of the spectrum, whether the cab is sealed or vented has no effect on the impedance curve, but if we want to minimize the tonal difference between using a solid state amp and using a tube amp, the impedance curve should be kept fairly smooth. Here's why: Assuming we have a cab voiced so that it sounds right on a solid state amp, using a tube amp will result in a frequency response peak wherever we have an impedance peak, and a frequency response dip wherever we have an impedance dip. This could easily lead us to the erronous conclusion that "tube amps suck" when in fact the problem is a speaker/amplifer mismatch. The smoother the impedance curve, the less change in the cab's tonal signature with different amplifier types.

Here is a paper on the subject written by a tube amp designer, who explains the "voltage paradigm" and the "power paradigm" better than I have. The author is the recipient of the largest collection of "Golden Ear" awards from The Absolute Sound magazine of any manufacturer:

Competing paradigms in amplifier and speaker design

 

[R Baer]

I do believe the only thing that matters is being right.

All this talk of sealed or ported, SVT or fEARFul, blah, blah, blah is nothing more than yet another excuse to prove one's point, and the point being how right we are.

Here's a question for y'all...

"Why no ported Ampeg 810 SVT's?"

Duh...

Simply pointing out that some players like the sealed cabs and some don't. Some players like P-Basses and some like Jazz basses. I get that the loyal fEarful crowd loves the design, but players also like their Ampeg, Bergantino, whatever, sealed cabs, because they (believe it, or not) actually prefer the "tone" and response these cabinets provide. There is no "better" when it comes to something as subjective as tone.

 

[JimmyM]

The 3015LF absolutely crushes the 8x10 when you start looking at a tone profile where you have as much volume at 60hz as you have at 200hz (literally, a single 3015LF performs as well as two sealed 8x10s once you scoop all the stuff above 100hz down to flat).

Are we playing bass or trying to make our basses sound like the inside of Flavor Flav's car trunk? If the latter, then your comparison would be germane to the discussion

However, when it comes to utility, I would argue that the 3015LF+Mid cabs are far, far more flexible. Getting an 8x10 to sound like a fEarful is infinitely harder than getting a fEarful to sound like an 8x10 (or at last close enough for gubmint work). Dialing in low mid punch is easy, dialing in low end to speakers that simply cannot produce it - not so much.

That's assuming you'd want it in the first place. I'm not much of a fan of that much low end. What I like about the low end of the 810 is that you don't have to dial out the good lows above 100 that are way more important to me than the lows below 60. My experience with cabs like the fEarful are very limited, yes, but my experience with the 410hlf is pretty extensive, and in order for me to get the EQ the way I want it with the SVT and 410hlf, I have to use the VT, otherwise I end up cutting too much off the lows in the frequency range that I like.

OTOH, I'm certainly not going to rag on the designs that use the LF speakers because they do a hell of a job. Just understand that those of us who doggedly love the 810e despite it being a big giant albatross of a cab have reasons for it, none of which have to do with how pretty it is

 

[rpsands]

Man, the idea that having the same amount of bass as midrange is some kind of extreme tone setting just boggles my mind

 

[R Baer]

Play whatever makes you perform well. Everyone's got opinions on gear, some are educated, some are not and that's perfectly OK too. In the end, you must decide what's right for you.

Which again answer the OP's original question. Why no sealed fEarful designs? Because the fEarful fans are not likely to dig the reduced low end response of a sealed cabinet, while the sealed cab guys are perfectly content with the sound of their cabinets.

 

[JimmyM]

Man, the idea that having the same amount of bass as midrange is some kind of extreme tone setting just boggles my mind

Hey man, we don't all play hip hop

 

[JimmyM]

Which again answer the OP's original question. Why no sealed fEarful designs? Because the fEarful fans are not likely to dig the reduced low end response of a sealed cabinet, while the sealed cab guys are perfectly content with the sound of their cabinets.

That's really about the long and short of it, isn't it?

Everyone should be as open-minded as me...I love the 810e, but I'll darn sure take a fEarful or similar, too. The idea that one should have to pick a side and stick with it is foreign to me.

 

[seamonkey]

Good point. I'd like to elaborate a little bit, at the extreme risk of going off-topic...

I would say that tube amps and solid state amps both interact with speakers, but they do so differently. Most speakers are designed for solid state amps, so it seems like the tube amp is the one that's interacting strangely, but arguably it interacts less with the speaker's impedance curve.
...

A thousand words:

Or just reach for the EQ knobs - that's what they are there for. You'll have an easier job EQ'ing a good full range fEarful type design to this curve.

That's a 1981 Solid-state by the way.

 

[JimmyM]

A thousand words:

It may be devoid of any context whatsoever, but it's a graph so I believe it. Now I understand why nobody uses tube amps anymore, and why nobody who makes solid state stuff tries to imitate tube amps. Thank you, Seamonkey. Once again, you saved us all.

 

[thudfromafar]

I completely understand that some would prefer tube amps just as I prefer SS. But I'm thankful for Duke's post and seamonkey's graph. I remember a period where I experimented a lot with winISD, looking at impedence curves and other things - a year ago, Duke's post would have made zero sense to me. But I actually understood what he was saying now.

 

[JimmyM]

I completely understand that some would prefer tube amps just as I prefer SS. But I'm thankful for Duke's post and seamonkey's graph. I remember a period where I experimented a lot with winISD, looking at impedence curves and other things - a year ago, Duke's post would have made zero sense to me. But I actually understood what he was saying now.

I might have appreciated seamonkey's graph a little more if I didn't know it comes from his weird obsession with stamping out tube amps.

 

[DukeLeJeune]

Seamonkey, if I understand correctly the implications of your graph, the speaker's impedance curve probably looks something like the tube amp's frequency response curve. That would be normal for a raw speaker in free air or in a lightly stuffed sealed box.

I think the graph is incorrect in the very low bass region. The speaker would probably have nearly the same very low bass output on the tube amp as on the solid state amp; certainly not the discrepancy depicted.

If we started out with a speaker whose frequency response was smooth with a tube amp, the response curve with the solid state amp would look like the inverse of the tube amp's curve, assuming the speaker had the same impedance curve (which we can't see, but it's implied by the response curve with the tube amp).

If we had a crossover that smoothed out the rising impedance of the speaker, and put it in a low-tuned vented box, we'd end up with approximately the same frequency response on the tube amp as on the solid state amp north of 100 Hz, and south of 100 Hz, depending on the specifics, we might be able to extend the bass as much as 1/3 octave deeper while doing away with that big response peak at the same time.

 

[staindbass]

A thousand words:

Or just reach for the EQ knobs - that's what they are there for. You'll have an easier job EQ'ing a good full range fEarful type design to this curve.

That's a 1981 Solid-state by the way.

what does this graph illustrate ? damping factor or impedance or frequency response? the tube line looks like a speaker impedance curve.

 

[billfitzmaurice]

I would say that tube amps and solid state amps both interact with speakers, but they do so differently. Most speakers are designed for solid state amps, so it seems like the tube amp is the one that's interacting strangely, but arguably it interacts less with the speaker's impedance curve.

+1. Ampegs recent woes that Jimmy is too aware of probably stem from overlooking this fact.

what does this graph illustrate ? damping factor or impedance or frequency response? the tube line looks like a speaker impedance curve.

Who knows? It's not impedance, impedance is not measured in decibels. What's more pertinent is this sealed (blue) versus ported (red) trace:

Tubes don't like higher impedance loads, so the lower maximum impedance of the sealed cab is more tube friendly. SS prefers higher impedance loads as that reduces current demand, so they're happier with ported. But again the skills of the designer (or lack of same) enter the equation, as you can tweak the impedance to suit specific needs.

 

[john turner]

what does this graph illustrate ?

regardless of the provenence of this particular data, this graph _definitely_ illustrates how graphing a logarithmic quantity on a linear scale can seriously exagerate the quantities being measured and imply to the layman a much greater difference in measurement than is really present.

 

[Sundogue]

Simply pointing out that some players like the sealed cabs and some don't. Some players like P-Basses and some like Jazz basses. I get that the loyal fEarful crowd loves the design, but players also like their Ampeg, Bergantino, whatever, sealed cabs, because they (believe it, or not) actually prefer the "tone" and response these cabinets provide. There is no "better" when it comes to something as subjective as tone.

Exactly. So why would Ampeg want to change an Ampeg SVT 810 into a ported cab, anymore than greenboy making a sealed fEARful?

Pointless. So why the question? Why not ask why Ampeg (or any other maker), why they don't design something other than what they design?

 

[chunkstyle]

Exactly. So why would Ampeg want to change an Ampeg SVT 810 into a ported cab, anymore than greenboy making a sealed fEARful?

Pointless. So why the question? Why not ask why Ampeg (or any other maker), why they don't design something other than what they design?

The OP is merely seeking information and enlightenment. The question asked certainly was not a call to arms.

 

[Sundogue]

The OP is merely seeking information and enlightenment. The question asked certainly was not a call to arms.

I'm not defending fEARfuls. I'm simply (as you put it) enlightening the OP.

Why don't they make Ferrari's full time 4 wheel drive? I like to go muddin' but I like Ferrari's.

And let's face it, this thread not only has become a "sealed vs. ported" thread, it's even started a "tube vs. solid state" debate. To what purpose?

If one likes sealed cabs, look for sealed cabs rather than asking why someone who didn't design a sealed cab, why they didn't design one?