Alternative to Kappalite 3015

[Downunderwonder]

Clear as mud. Damn this language gap. I think you're saying my low mid is your lows, everything one octave out, but warm is what freq to you?

 

[beate_r]

Warmth ... usually not any specific frequency range. Translate it to "musically meaningful distortion, not too strong" in the sense of increased k2 or k4. Or maybe some nicely sounding breakup.

 

[Downunderwonder]

Wow, the other end of the bass range. No wonder we aren't on the same page. Most others too I'll wager.

T/S has nothing to do with that range you know?

 

[Arjank]

The problem is that what some people call breakup is what others call increased harmonic distortion....

I did write about "breakup" in some thread lately, trying to explain a thing or 2.....

 

[beate_r]

T/S has nothing to do with that range you know?

Yes, i do. That's why my thread is named "alternatives to..."

 

[Downunderwonder]

Right, now it makes sense!

 

[beate_r]

Let me come back to this one:

... a non-LF 3015...from large to medium size. In all of them it sounded too mid-heavy to me. ... last cab ...my Ibanez Promethean P3115. Its about 2.0 cu feet. ... ... tuned to 47hz. ... Here it sounds loud,clear and deep. I'm just confused that it sounds the best in the smallest amp/cab I have, but it has really improved the performance of this combo so much that it is a perfect match.

I ran that example through LSPCAD:

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The TSP of the 3015 are surprinsingly close to those of the Beta-12. I would expect the Beta-12 to perform nicely in such a resonator as well. It is good even in 35 l tuned to something around 57 Hz, really punchy. I am currently using it in 55 l / 55 Hz and like it very much. (The 35 l box now runs a Beta-10, just fine for practising at home)

Who might the 3015 perform in a similar setting? Here its simulation in 60l / 55 Hz.

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Nice. The simulation of a single Beta-12 looks pretty similar, just not as loud.

Actually a pair of Beta-12 has almost the sensitivity of one 3015, as a pair it also almost reaches the Vd of the 3015, and the power ratings are also close. To far less than 2/3 of the price of a 3015, and in a total volume comparable to that of my current cab for the 3015.

So - if the 3015 performed well in a (lightweight) cab of only 60 l, in either or both of the settings shown above, that would be a dream of a box.

 

[ThisBass]

Warmth ... usually not any specific frequency range. Translate it to "musically meaningful distortion, not too strong" in the sense of increased k2 or k4. Or maybe some nicely sounding breakup.

Harmonic numbers of k2 or k4 would mean the speaker excursions are not symmetrical.

In general the Harmonic numbers due to symmetrical limitation are k3, k5, k7 ...
Which is independent of soft or hard clip limitation.

Whereas none symmetrical limitation means k2, k3, k4, k5 ....
Which is independent of soft or hard clip limitation as well.

 

[beate_r]

Please keep in mind that harmonic distortion is inherent to any movement of the speaker cone, even the smallest one.

 

[ThisBass]

Please keep in mind that harmonic distortion is inherent to any movement of the speaker cone, even the smallest one.

Which means k2, k3, k4, k5 ...
Preferences of k2 or k4 are not possible.

Whereas preferences of k3 and k5 are indeed possible.

 

[beate_r]

Nothing worth to be debated upon without measurements.

 

[ThisBass]

Nothing worth to be debated upon without measurements.

But this is told by Fourier Analysis as you know?
Symmetrical versus asymmetric tells the figures of k.
There is no need for any measurements unless the speaker is of rubbish.
To tell it in other words it's a kind of math.

 

[5port]

Let me come back to this one:



I ran that example through LSPCAD:

Invalid Link Removed

The TSP of the 3015 are surprinsingly close to those of the Beta-12. I would expect the Beta-12 to perform nicely in such a resonator as well. It is good even in 35 l tuned to something around 57 Hz, really punchy. I am currently using it in 55 l / 55 Hz and like it very much. (The 35 l box now runs a Beta-10, just fine for practising at home)

Who might the 3015 perform in a similar setting? Here its simulation in 60l / 55 Hz.

Invalid Link Removed

Nice. The simulation of a single Beta-12 looks pretty similar, just not as loud.

Actually a pair of Beta-12 has almost the sensitivity of one 3015, as a pair it also almost reaches the Vd of the 3015, and the power ratings are also close. To far less than 2/3 of the price of a 3015, and in a total volume comparable to that of my current cab for the 3015.

So - if the 3015 performed well in a (lightweight) cab of only 60 l, in either or both of the settings shown above, that would be a dream of a box.

Wow thanks for running these numbers. So using an online converter 2.1 cu feet is about 60L. Looks like its a good match which in reality does sound good. I picked 47hz because it was slightly above the Fs freq so I wanted to play it safe. It paid off.

 

[ThisBass]

Wow thanks for running these numbers. So using an online converter 2.1 cu feet is about 60L. Looks like its a good match which in reality does sound good. I picked 47hz because it was slightly above the Fs freq so I wanted to play it safe. It paid off.

That's a very wrong conclusion to build up cab designs.

 

[beate_r]

But this is told by Fourier Analysis as you know?

If You have the equipment to record the pulse response reliably.

Aside from this we should ask to which degree it is meaningful to put such properties in numbers. Take for example, the Beta-12. I own mine for several years now and have run in in several cabinets, also experimental ones. I have at least a qualitative feeling of what comes from the speaker what from the cab (resonances) and to some degree of the interaction of that system with the surrounding. So what do i need measurements for?

At present i think of trying the 3015 in a 60 l cube. I am still a bit unsure of the material, maybe 18 mm massive spruce, not despite but because of its untamable resonances, maybe 18 mm massive beech (mmhm, will become heavy...), maybe again 12 mm plywood, maybe chipboard - 12 mm or 19 mm ...

 

[beate_r]

That's a very wrong conclusion to build up cab designs.

Anyway, the simulations indicate that such a setup would work - although the tuning might be a bit higher, IMHO.
BTW: Extrapolating between the manufacturer's recommendation for medium and small cab will also lead to a tuning frequency in the range i would prefer.

And again: the port-tuning of the 3015 is not what we are discussing here.

That "midrange emphasize" of the chassis must be something different, mostly a property of the speaker, which is more or less emphasized by the properties of the cab

 

[ThisBass]

If You have the equipment to record the pulse response reliably.

Impulse response tells something about the damping of the system. The system includes amplifier and cabinet.

Aside from this we should ask to which degree it is meaningful to put such properties in numbers. Take for example, the Beta-12. I own mine for several years now and have run in in several cabinets, also experimental ones. I have at least a qualitative feeling of what comes from the speaker what from the cab (resonances) and to some degree of the interaction of that system with the surrounding. So what do i need measurements for?

At present i think of trying the 3015 in a 60 l cube. I am still a bit unsure of the material, maybe 18 mm massive spruce, not despite but because of its untamable resonances, maybe 18 mm massive beech (mmhm, will become heavy...), maybe again 12 mm plywood, maybe chipboard - 12 mm or 19 mm ...

Plywood is best because "resonances" are reduced.
Modeling Tools provide an additional parameter named QL.
QL is the quality factor of the cab design.
QL=7 represents a standard cab design with reduced losses.
QL=15 or greater represents lightweight designs with lots of resonances.

your present cab is estimated to come with Vb appro 75..80 Liter? Probably this is rather the total volume.
I can't imagine that such a small cab like yours contains of such a big net volume like 80 Liter.

Therefore may be the port dimensions of the present cab was wrong calculated?

I estimate the net volume Vb of your present cab to appro 60 Liter.
Frequency response looks fine for fb 55..60Hz.
(QL=10 with minimal/typical Fill).

 

[ThisBass]

Anyway, the simulations indicate that such a setup would work - although the tuning might be a bit higher, IMHO.

In general higher tunings give more tone to the 2nd Harmonic of the instrument.
The 2nd Harmonic gives all of the necessary sound "fundamentals".
There is no need to reinforce the 1st Harmonic.


Alternative to the Kappalite:
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[beate_r]

Impulse response tells something about the damping of the system. The system includes amplifier and cabinet.

Its Fourier transform yields the frequency response (in a purely linear approach).

your present cab is estimated to come with Vb appro 75..80 Liter? Probably this is rather the total volume.
I can't imagine that such a small cab like yours contains of such a big net volume like 80 Liter.

The volume comes from its depth. Anyway, as shown in the old photo, VB was about 71 Liter, and the tuning of the port must have been far too low. A while ago i increased the port area to > 300 cm^2 (its visible height from 3 to 8 cm) and thus also Vb (by the additional volume behind the port).

Therefore may be the port dimensions of the present cab was wrong calculated?

It is actually higher than estimated (~56 Hz instead of the intended 51.5 Hz). The models are a bit inaccurate because they do not take into account that this cab is equipped with a shared wall port. That's why the tuning frequency initially was far off.

I estimate the net volume Vb of your present cab to appro 60 Liter.

60 Liter with a square front of 40x40 cm corresponds to a depth of 37 cm + thickness of the sides. Accordingly, increasing the depth to ~47 cm yields 75 Liter. Plus, of course, the volume behind the port.

I do not want to cut the (expensive) plywood into pieces for the next attempt, just build a working prototype from cheap materials.

 

[ThisBass]

Its Fourier transform yields the frequency response (in a purely linear approach).

Ähm, yes and no.

An ideal pulse response shows little ringings of over- and undershooting.

There are no ringings at all If the damping of the system is to high.
That would be the overdamping case.

But there will be very significant ringings if damping is to weak.
The amount of damping depends on the amplifiers ability to work as a controller which is based on its negative feedback loop. And as well on the cabs mechanical system resonance.

If an amplifier would not be equipped with a feedback loop would mean very significant ringing at pulse response.

To get as close to the ideal damping (aperiodic boundary case) as possible is the reason for why the choice of speaker cables are very often bigger in diameter then it is necessary for the current.


Drawing a frequency response from pulse response (periodically Dirac pulse).
I have no idea if this technique of frequency response measurement will be practical for loudspeakers.
Probably a conventional approach with sine sweep is easier to handle.

Whereas the Dirac pulse response is imaginable in the field of quality check where taking as little time as possible is a factor of production costs