Most important speaker spec?

[amos]

Other than actually testing out a speaker cabinet, and disregarding companies lying about specs, what is the specification that will give the best information towards real-world application?
Sensitivity? And I was also wondering what the difference between sensitivity and efficiency is? I'm thinking efficiency is speaker-releated, sensitivity is overall cabinet-related, is that right?

 

[Nick Kay]

Efficiency is power out divided by power in, or acoustic energy over electrical energy. In speakers, this is typically around 5%, meaning over 90% of your amp's big ol' power section gets wasted off as heat or something else that's completely useless to us.

Sensitivity, on the other hand, is a rating of how much sound pressure the speaker produces under x amount of power. The standard rating is at 1w or 2.83V in an anechoic environment.

 

[meev992]

Besides efficiency, I would probably put ohms, somewhere on the list of most important speaker specs.

 

[GreyBeard]

I always look at sensativity, gives me an idea of how much power it needs.

 

[T-Bird]

Hi, amos.

I'd say a thumbs up from TB community would give a good indication .

Just my 0.02€
Sam

 

[billfitzmaurice]

what is the specification that will give the best information towards real-world application?

Displacement limited power across the frequency bandwidth. If the average player knew how little power his cab was actually capable of taking at 80 Hz he'd cringe.

 

[greenboy]

To break down further what Bill is saying, xmax - useful excursion - of the woofer interacts with a given box internal volume and tuning, and limits how much output is actually available at lower frequencies, and how easy it is to fart and even "hit the backplate"... And with the drivers being used in bass cabs, the wattage the cab can take at those lower frequencies, even briefly sustained, is often only 1/4 to 1/3 the speaker's "RMS"/thermal rating. And I've seen worse cases yet..

 

[greenboy]

The Thiele-Small paramater, Sd, by the way, is the xmax times the speaker cone area (Vd). The 15" Em Kappalite 3015LF has a Vd of 846 compared to the 10" Em DeltaliteII 2510's 147.

Big diff!

 

[Bryan316]

YOUR EARS


A test drive, so you can actually hear it, is far more important than any numbers or charts. Cuz if the cab has monstrous wattage handling and efficiency, but sounds like a wet cat smacked with a 2x4, then you ain't gonna be happy no matter what.

 

[greenboy]

...Which inevitably takes us to the next rung: bass cab manufactuers are notorious for specsmanship. Their numbers have so little to do with actual audio performance as to be discounted entirely. Only a few companies on a few products actually provide qualified specs that actually relate to real world performance. But unfortunately since nobody else is playing an honest game, the specs cannot be used to make accurate comparisions that have any bearing.

If you get the T-S parameters of the drivers used in your cabs that will actually allow you to get a more accurate idea of what is going on than anything the cab manufactuers use in their marketing. So continue to use the ears, please ; }

 

[scotch]

YOUR EARS


A test drive, so you can actually hear it, is far more important than any numbers or charts. Cuz if the cab has monstrous wattage handling and efficiency, but sounds like a wet cat smacked with a 2x4, then you ain't gonna be happy no matter what.

But,... but,... isn't tone an inverse coefficient of the potential xmax divided by the Vb in relation to the cosine of peak power handling minus the specific gravity of the cabinets' cover material? (I think I forget to carry the three)

Sorry, I do love the speaker cabinet/driver threads!

 

[generation land]

I asked this question the other day with no answer. It sounds like this group can help, what do you think?
--------------------------------------------------------------------------------

Here are the specs for a freebe speaker I have, can you sugest some cab specs. I have a friend that is handy with wood that is willing to help me. I will be paring this with a SWR Goliath 4x10 cab.
Thanks for any help.
John

SPECIFICATIONS

Nominal Basket Diameter
15" / 380mm

Impedance
8 ohms

AES Continuous Pink Noise Power 600 Watts
Frequency Response
30Hz - 2.5kHz

Sensitivity (1W/1m)
97dB

Voice Coil Diameter
4" / 100mm

Max. Crossover Frequency
1.2kHz

Voice Coil Material Edgewound Aluminum Ribbon
Voice Coil Winding Depth 19.05mm
Magnet Weight 6.8 kg / 15lbs.
Recommended Enclosure Volume 85-285 Liters / 3-10(ft3)
MOUNTING INFORMATION

Overall Diameter 15.27" / 388mm
Bolt Circle Diameter 14.5625" / 370mm
Baffle Cutout Diameter 14.0" / 355mm
Overall Depth 5.5" / 137mm
Net Weight 8.7 kg. / 19.125 lbs.

THIELE-SMALL PARAMETERS

Resonant Frequency (fs) 40 Hz
Impedance (Re) 5.0 ohms
Coil Inductance (Le) 1.75mH
Mechanical Q (Qms) 5.0
Electrical Q (Qes) .33
Total Q (Qts) .31
Compliance Equivalent Vol. (Vas) 175 Liters/6.2cu. ft.
Voice Coil Overhang (Xmax) 7.6mm
Reference Efficiency 3.3%
Effective Surface Area (Sd) .088 m2

 

[billfitzmaurice]

I asked this question the other day with no answer. It sounds like this group can help, what do you think?

My fee for designing a cabinet is $2,000.
Download WinISD (linearteam.org) and you can come up with your own for free.

 

[greenboy]

Failing the patience to read any books about speaker design, I'd say at least wade through the HELP files for WinISD Pro and model some drivers in the program and look at the various graphs. Mull over the stuff you don't understand, and post about THAT, and even make sure there aren't things you think you understand but really don't ; }

Then you have the beginnings of an understanding and can actually make some intelligent design decisions.

If that doesn't sound too appealing, just buy pre-made cabs ; }

 

[Crockettnj]

My fee for designing a cabinet is $2,000.
Download WinISD (linearteam.org) and you can come up with your own for free.

OT, Bill

Have you ever designed a reflex cab for a bass cab co? (if yes, I'm not asking which one)

 

[Crockettnj]

Displacement limited power across the frequency bandwidth. If the average player knew how little power his cab was actually capable of taking at 80 Hz he'd cringe.

This really gets me thinking.

If the majority of a bass cabs power requirements to achieve the typical sound of a bass guitar lies in the lower freqs, say maybe below 250hz, then isnt the displacement limited power really an indicator of "how much amp" you need?

I am assuming that it would be a lower freq that limits your power. i am also assuming that higher freqs have far lower power demands.

in other words, of what use is the extra power beyond the disp limited power...

This, coupled with the listed thermal specs for the speaker, seem to REALLY REALLY skew the amp purchaser towards excess.

If a typical 1x10 DlII2510 cab is limited to say 65 watts at 80 hz, then of what use is a 150 watt amp, let alone a 250 watt one?

 

[chaosMK]

I care about voicing (if it can push low mids well... around 150-200hz) and weight.

I wouldnt stress about the specs in real world application, just ask the experts/nerds/enthousiasts here on TB. We know everything.

 

[MrLenny]

My Acme B2 2x10 has a SPL of 93
My Eden 2x10 XST has a SPL of 104.
To get rock n' Roll levels I have to drive the Acme @ full gain,
my eden I drive @ half gain.

 

[billfitzmaurice]

OT, Bill

Have you ever designed a reflex cab for a bass cab co? (if yes, I'm not asking which one)

Yes. I can't say for which (more than one), cab companies generally don't want it known that most of them do not have engineers on staff and that they source their designs. Also note that despite my recommendations, to lower production costs every cab design I've done has not been built to spec. The main alterations were reduced bracing and internal damping material.

if a typical 1x10 DlII2510 cab is limited to say 65 watts at 80 hz, then of what use is a 150 watt amp, let alone a 250 watt one?

To drive more cabs, or for plenty of clean headroom. Both are valid reasons. But if you do have a 250w amp and you can't get enough volume chances are it's not from not having enough power, it's probably from not having enough speakers to handle what you've got.

 

[bgavin]

My Acme B2 2x10 has a SPL of 93
My Eden 2x10 XST has a SPL of 104.
To get rock n' Roll levels I have to drive the Acme @ full gain,
my eden I drive @ half gain.

Measure it at 40 Hz, and let's see who wins, and who loses.

Cabs with 104 SPL sensitivity do not have a big bottom end. They can't. You can have any two from Low, Loud, Small in one box. Pick two. The XST is Small and Loud. Low is out.

The Acme is Small and Low, and Loud is out.