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Question about Bass Cab Speaker Pairing / Dimension / math etc.

#43
Ok, I ran a few numbers...
Will it work? Yeah.
Will it be great? no, not really.
Will it be "acceptable"? depends on the expectations, but IMO it's pretty poor.
(pardon the use of imperial units, that's how my software template is set up)

Sealed cabinet (6CF):
F3=96Hz
F6=67Hz
F10=50Hz
Sensitivity=~100dB/1W/1M
Power Handling <50Hz=400W

Ported cabinet (6CF, 2 x 5" diameter ports 4" deep):
F3=65Hz
F6=53Hz
F10=41Hz
Sensitivity=~101dB/1W/1M
Power Handling <50Hz=600W

White curve is ported, red curve is sealed, the area between the curves is the difference in performance (a lot):
1757613984322.png


So you have your answer, and should be able to (easily) see that using those drivers into the existing box as is cripples the performance significantly, since the drivers are optimized for ported enclosures.
 
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#44
agedhorse said:
Ok, I ran a few numbers...
Will it work? Yeah.
Will it be great? no, not really.
Will it be "acceptable"? depends on the expectations, but IMO it's pretty poor.
(pardon the use of imperial units, that's how my software template is set up)

Sealed cabinet (6CF):
F3=96Hz
F6=67Hz
F10=50Hz
Sensitivity=~100dB/1W/1M
Power Handling <50Hz=400W

Ported cabinet (6CF, 2 x 5" diameter ports 4" deep):
F3=65Hz
F6=53Hz
F10=41Hz
Sensitivity=~101dB/1W/1M
Power Handling <50Hz=600W

White curve is ported, red curve is sealed, the area between the curves is the difference in performance (a lot):
View attachment 7319465

So you have your answer, and should be able to (easily) see that using those drivers into the existing box as is cripples the performance significantly, since the drivers are optimized for ported enclosures.
Click to expand...
Perfect! This is an answer I will rely on! Thank you so much for running that through your system.

Any change another easily available 12 inch bass speaker could work better?

Amso I would be curious how the graphs on Lemmys or Steve Harris cab would look like. Probably also poor…
 
#45
raketenmann said:
Any change another easily available 12 inch bass speaker could work better?
Click to expand...
Yes of course!

I am by no means an expert. In regards to sealed VS ported compatibility, online sources suggest considering EBP and Qts. If I am reading the guidance correctly, EBP and Qts values for the Eminence Legend BP122 suggest it is better suited for sealed than the Pulse 12.

The BP122 Cab Design Doc includes, large, medium and small sealed cabs: https://www.parts-express.com/pedocs/specs/290-4810--eminence-legend-bp122-cabinet-design.pdf

I believe the large and small designs are a bit bigger and a bit smaller than the cab you are dealing with. Of course it would be best to model the BP122 in your actual cab.

Perhaps there is a better choice.
 
#49
Wasnex said:
? The spec sheets say the BP-122 has slightly higher sensitivity than the Pulse 12. 94.1dB vs 94dB.
Click to expand...
Except that there a lot to be gained (including sensitivity-wise) by using the Pulse in a ported cabinet.

The BP-122 will perform better (IIRC) than the pulse in a sealed cabinet, but still not as good as the Pulse in a ported cabinet.

There are better (higher sensitivity) options than the Pulse of course, but generally at a higher cost in the EU.
 
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#51
When you put together a DIY system, it always sounds better than the numbers indicate. Keep doing your homework and try to avoid second guessing your decisions.

The Celestion Pulse is used in the Orange410. Maybe you'll like the 12's.
 
#53
agedhorse said:
Ok, I ran a few numbers...
Will it work? Yeah.
Will it be great? no, not really.
Will it be "acceptable"? depends on the expectations, but IMO it's pretty poor.
(pardon the use of imperial units, that's how my software template is set up)

Sealed cabinet (6CF):
F3=96Hz
F6=67Hz
F10=50Hz
Sensitivity=~100dB/1W/1M
Power Handling <50Hz=400W

Ported cabinet (6CF, 2 x 5" diameter ports 4" deep):
F3=65Hz
F6=53Hz
F10=41Hz
Sensitivity=~101dB/1W/1M
Power Handling <50Hz=600W

White curve is ported, red curve is sealed, the area between the curves is the difference in performance (a lot):
View attachment 7319465

So you have your answer, and should be able to (easily) see that using those drivers into the existing box as is cripples the performance significantly, since the drivers are optimized for ported enclosures.
Click to expand...
Dear @agedhorse

Can you simehow predict how a speaker behaves that has no thiele smalls parameters available? For example, I am thinking of installing Celestion Neo Copperbacks. They have a solid 250W power handling and would probably survive some bass playing. It would then still be a guitar cab, but for occasionally bass playing probably useable. Also, that speaker has a very solid lowend extension….

Thx for your help again!
 
#54
raketenmann said:
Dear @agedhorse

Can you simehow predict how a speaker behaves that has no thiele smalls parameters available? For example, I am thinking of installing Celestion Neo Copperbacks. They have a solid 250W power handling and would probably survive some bass playing. It would then still be a guitar cab, but for occasionally bass playing probably useable. Also, that speaker has a very solid lowend extension….

Thx for your help again!
Click to expand...
Sadly no. The TS parameters are how you predict how a speaker behaves. Actually, they're a set of statistics about the speakers, but whatever.

Don't let the naysayers put you off. You seem to have realistic (low) expectations of what you're planning so just have fun. If you have the inclination you would almost certainly benefit from some bracing and some insulation.
 
#55
raketenmann said:
Dear @agedhorse

Can you simehow predict how a speaker behaves that has no thiele smalls parameters available? For example, I am thinking of installing Celestion Neo Copperbacks. They have a solid 250W power handling and would probably survive some bass playing. It would then still be a guitar cab, but for occasionally bass playing probably useable. Also, that speaker has a very solid lowend extension….

Thx for your help again!
Click to expand...
Not really, without doing some lab work to extract the parameters.

The low frequency rolloff of the Copperbacks isn't really suitable for bass, and there's going to be little Vc overhang which will limit the mechanical power handling to about 100 watts below about 200 Hz.

Yes it will work, maybe ok at low-ish volume, but that's a lot of cabinet for the volume limitations imo,m.
 
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#56
The OP wants a cool looking cabinet and likes an old school tone so I would imagine that the 4 pulse drivers in a ported cabinet would meet his requirements.

New drivers in old cabs can sound fine
Since you know the volume and can model a whole range of drivers.
You can also modify the front baffle to give even more options
 
#57
Drredplate said:
The OP wants a cool looking cabinet and likes an old school tone so I would imagine that the 4 pulse drivers in a ported cabinet would meet his requirements.

New drivers in old cabs can sound fine
Since you know the volume and can model a whole range of drivers.
You can also modify the front baffle to give even more options
Click to expand...
Maybe, maybe not... but since I did the math in post 43, we know the answer rather than needing to guess.
 
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#59
Drredplate said:
Yes I read your post and fair play for doing the maths for him.
On the basis that he's setting the bar fairly low my interpretation of you data was that it would do what he wanted.
Click to expand...
If mediocre is acceptable, then it will be "just fine"...
 
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