Speaker cabinet sensitivity : relevant?

[SilkyStrings]

'So if you have 2 102db JBL 15s in a cab for 105db at 1w/1m, and a 96db 4x10, you can get the same volume out of 100w that you could with 400 from the 4x10.'

Is this the reason why bass amps have been getting more powerful? i.e. to power smaller and less efficient bass cabinets. I remember my Dad playing through a 100watt head into a 2x15 cabinet back in the 70's and he always said if he stood in front of it his bell bottoms were flappin'!

[Downunderwonder]

Closer to 1000W for the 4x10 to try to match that JBL 2x15 with 100W, yes sensitivity is important.

[staccatogrowl]

Originally Posted by agedhorse

Good grief, I haven't lost my mind?

No, but I am still pondering "sensitivities" of alcohol influence in relation to the number of blonds in the room. Is there an online calculator for that as well?

[Arjank]

Originally Posted by SilkyStrings

Is this the reason why bass amps have been getting more powerful? i.e. to power smaller and less efficient bass cabinets. I remember my Dad playing through a 100watt head into a 2x15 cabinet back in the 70's and he always said if he stood in front of it his bell bottoms were flappin'!

Yes

Nowadays there are lot's of cabinets that sport drivers with extended xmax, lower Fs and small Vas. This not only includes longer voicecoils but also changes the design for the magnet structure, the spider and suspension. And, most of the time the cone is (a lot)heavier. All in all it takes more power to drive these kind of drivers at the same spl level as the older types.
If you only have a 100watt amp and need to fill the stage you got to have efficient loudspeakers like these ol' 15" JBL's or Altec's. Or you have to build some of these horns or bassbins.

[KJung]

Originally Posted by SilkyStrings

'So if you have 2 102db JBL 15s in a cab for 105db at 1w/1m, and a 96db 4x10, you can get the same volume out of 100w that you could with 400 from the 4x10.'

Is this the reason why bass amps have been getting more powerful? i.e. to power smaller and less efficient bass cabinets. I remember my Dad playing through a 100watt head into a 2x15 cabinet back in the 70's and he always said if he stood in front of it his bell bottoms were flappin'!

+1 That is why it is such a wonderful world to be a bass player today. You can get true low end and impressive volume out of a cabinet a fraction the size of those old 215 boat anchors. You pay for that by needing more power, which these days is very cheap.

[CL400Peavey]

Originally Posted by agedhorse

Something else to note is that while the raw sensitivity number may be important, it's also important to know how this number is derived. Things like measured bandwidth, boundery conditions and at what power level the number is normalized to all factor into the real world sensitivity.

+1

Sensitivity is important, but published sensitivity specs are not to be trusted. There is a lot of grey area on how these measurements are derived. When you see specs for a 410 that surpass any combination of 10" speakers you be begin to wonder. For me the biggest tell is what frequency the sensitivity measurement is taken at. A driver that has a 102 db sensitivity at 2kHz but is down 15-20 db at 100 hz isnt much use for me. Its not really practical for most to support and maintain four 215's loaded with old JBL's just so they can gig their low powered head. Its not about money so much as logistics.

Originally Posted by KJung

+1 That is why it is such a wonderful world to be a bass player today. You can get true low end and impressive volume out of a cabinet a fraction the size of those old 215 boat anchors. You pay for that by needing more power, which these days is very cheap.

+1

Power is cheap, and light, and easy to come by. I understand chasing a tone in your head, but practicality of implementation is important too.

[MrLenny1]

My 2 cents.
My Acme II 2x10 had an SPL of 93.
My Eden XST 2x10 has a SPL of 104.
Liked the Acme but it did not cut thru the mix very well.
The Eden certainly does.

[Arjank]

Originally Posted by MrLenny1

My 2 cents.
My Acme II 2x10 had an SPL of 93.
My Eden XST 2x10 has a SPL of 104.
Liked the Acme but it did not cut thru the mix very well.
The Eden certainly does.

Thats not because of the Eden having better efficieny (in the mids/high) then the Acme but because the response of the Eden starts to roll off from the lowmids compared to the Acme(or if you look at it the other way around, the Eden having more mids and highs then the Acme). With the Acme you probably had to dial in some mids to let it cut through.

My 210 with coaxial mid driver has an efficiency of 97dB. Though it does sound louder and cuts better then an Eden 210 XST because the off-axis response is much better. (yes, I did compare them side by side) see post #165 in this thread Building a superior 2x10 cab

[Mr. Foxen]

Originally Posted by Arjank

Thats not because of the Eden having better efficieny (in the mids/high) then the Acme but because the response of the Eden starts to roll off from the lowmids compared to the Acme(or if you look at it the other way around, the Eden having more mids and highs then the Acme). With the Acme you probably had to dial in some mids to let it cut through.

My 210 with coaxial mid driver has an efficiency of 97dB. Though it does sound louder and cuts better then an Eden 210 XST because the off-axis response is much better. (yes, I did compare them side by side) see post #165 in this thread Building a superior 2x10 cab

Its mostly down to Eden's sensitivity specs being the most dubious I've encountered.

[CL400Peavey]

Originally Posted by Mr. Foxen

Its mostly down to Eden's ... specs being the most dubious I've encountered.

Fixed that for ya.

[bgavin]

Here is a Link to D410XLT Chart.

This was taken 2007.11.01, outdoors.
It is 2.83v into 8 ohms, or 1W/1M, ground plane.
The RTA SPL was calibrated by DVM at 2.83v at 100 Hz.

[CL400Peavey]

Originally Posted by bgavin

Here is a Link to D410XLT Chart.

This was taken 2007.11.01, outdoors.
It is 2.83v into 8 ohms, or 1W/1M, ground plane.
The RTA SPL was calibrated by DVM at 2.83v at 100 Hz.

Since im on a phone and I cant read much of that, what kind of average are we looking at?

[bgavin]

94 dB at 40 Hz
114 dB at 450 Hz.
94 dB at 6 KHz
85 dB at 10 KHz

+/- 10dB "usable range" is 40~6000 Hz.
The mid point of this range is 104 SPL.

[Arjank]

Originally Posted by CL400Peavey

Since im on a phone and I cant read much of that, what kind of average are we looking at?

On average between 100hz and 1.5khz it's 107dB
Between 40hz - 6hz it would indeed be around 104 -103dB.

[Bassmec]

Originally Posted by Arjank

On average between 100hz and 1.5khz it's 107dB
Between 40hz - 6hz it would indeed be around 104 -103dB.

I think that's quite respectable really for a 4 x 10 that's why I chose the Eden 8 x 10 LXT for the clean side of my clean dirty tube amp rig.
Lots of clean apparent volume for not that much in watts, My most efficient speakers are still my Altec 418 series II option drivers in old metal badge Ampeg SVT 115's they are real loud per watt and have slightly more bass end than the also very loud JBL D130 that sounds great clean or filthy too.

[will33]

It looks to me how an Eden sounds...like a giant frowny face.

Very strong output from the highbass/lowmids through the middle mids with much less than that below about 100hz to above 1-1.5khz or so.

If you view RTA's of the World Tour amps, they are pretty smooth/flat with lots of EQ capabilities. The "voice" comes from plugging into their cabs.

[BogeyBass]

I think I remember having this argument before about Edens specs.

Not many but there is a few 10's that hit around 98dB

so a 410 could be around 104dB

So when Eden said 106dB it just seemed impossible....but
if you average from 125 to 4K it is pretty darn close to 106dB....No?

But then of course a 10" that can actually hit 98dB usually does not have much lowend and it would have large peaks in the midrange that anybody could fudge some pretty high numbers.
How amazing it actually sounds for bass is questionable. But hey it looks really pretty on paper. And it sure looks good at 106dB on your website.

Some JBL 15's can have 105dB peaks, but have a more realistic average of 102dB. Same thing amazing midrange peaks but very little lowend.

But say in a PA using a crossover for a very narrow band
A 15" being used for its actual purpose as a midbass would be smoking loud.

[will33]

All these abstract sensitivity specs you see in ads are one reason why a 1/2 space measurement is, or should be, the standard. The proverbial "playing in an open field". It keeps all the different speakers being measured on a level playing field. Though many of us maybe don't play in true 1/2 space very often, though I do a outdoor courtyard type gig once a month that's pretty close....open air festival gigs may also be pretty close aside from speaker stacks sitting around, etc....once you go smaller than 1/2 space...say to "better simulate the environment the player is in", you get to where no two rooms are absolutely identical in every way...various boundries come into play...and the comparisons are no longer valid as company A's measurements are no longer identical to company B's, etc.

[Mr. Foxen]

All a bit meaningless without the same info for a different cab. Just working on sensitivity figures for comparison, that is louder than two SVT8x10s with same power.

[will33]

Originally Posted by BogeyBass

I think I remember having this argument before about Edens specs.

Not many but there is a few 10's that hit around 98dB

so a 410 could be around 104dB

So when Eden said 106dB it just seemed impossible....but
if you average from 125 to 4K it is pretty darn close to 106dB....No?

But then of course a 10" that can actually hit 98dB usually does not have much lowend and it would have large peaks in the midrange that anybody could fudge some pretty high numbers.
How amazing it actually sounds for bass is questionable. But hey it looks really pretty on paper. And it sure looks good at 106dB on your website.

Some JBL 15's can have 105dB peaks, but have a more realistic average of 102dB. Same thing amazing midrange peaks but very little lowend.

But say in a PA using a crossover for a very narrow band
A 15" being used for its actual purpose as a midbass would be smoking loud.

Yep. It's pretty crazy how loud one can get with how little when you take the pressure of making LF off of them.


Example: Look at the datasheet for a 12" Deltalite II. Due to the rising midrange and upper peak, the average is 99.9 across the usable bandwidth for one driver. I use 2 of those in my rig. Doing it that way, I coukd tell people it's 103db and easily rivals an 810 at 1/3 the size and weight. Truth is it's not and it doesn't. It's more like 99-100 for the pair where it counts...that being maybe 60hz up through the middle range.