Speaker Specs- What's going on? A little quiz for you...

[VictoriaGuy]

Most of the time, I'm looking at amp specs, so I've gotten accustomed to the -3dB 'standard' which seems to be used when specifying frequency response.
I'm shopping for new speaker drivers these days.

Quiz:
One of the following speakers has a freq range advertised as (40Hz to...) and the other is advertised as (51 Hz to.....)
Can you guess which from the freq response curves?

I think I need some education here - please help!

[chrisb]

Originally Posted by VictoriaGuy

Most of the time, I'm looking at amp specs, so I've gotten accustomed to the -3dB 'standard' which seems to be used when specifying frequency response.
I'm shopping for new speaker drivers these days.

Quiz:
One of the following speakers has a freq range advertised as (40Hz to...) and the other is advertised as (51 Hz to.....)
Can you guess which from the freq response curves?

I think I need some education here - please help!

Well, for one thing, Mark's published specs are much more "conservative" than Fostex's from the past (AFAIK, the published specs for the 168Ez haven't been revised)

There's approx 10dB difference in the sensitivity between these two, as well as almost half an octave in the "published" Fs 21Hz for the Fostex and 36 for the Alpair 10.

Further, while this particular model of Fostex will perform very well indeed, it does want to see a larger enclosure of the BLH or Voigt pipe family, while the Alpairs work very well in much smaller ported enclosures, MLTL / Scott Lindgren's Pensils, or the "Fonken" style tuning.

Secondly, Mark intentionally designs a fair degree of compensation into his drivers FR. Have you actually heard any of them? It's only a 15min drive away.

Thirdly, I won't say published FR specs are meaningless, but you already own the most accurate and calibrated set of test gear you really need, and they're entirely portable.

[VictoriaGuy]

Hi, Chris-
Thanks for the quick reply.

Originally Posted by chrisb

Well, for one thing, Mark's published specs are much more accurate than Fostex's from the past (AFAIK, the published specs for the 168Ez haven't been revised)

I didn't say I 'believed' either of the curves, but the Alpair is something like 30dB down at 40 Hz...
IF the Alpair curve is accurate and IF one were to use the -3dB convention, then the freq response should be 100Hz to..., no? And the Fostex driver should be about the same......

Originally Posted by chrisb

Secondly, Mark intentionally designs a fair degree of compensation into his drivers FR - have you actually heard any of them? It's only a 15min drive away.

I'm not criticising Mark's speakers- it's the general issue of published specs and how they are interpreted that I'm interested in. This comes up from time to time online- last time I was watching it was the AudioNirvana specs that were in question. At least Mark is apparently publishing accurate curves, which is a start.
I really don't like to waste your time and Dave's any more than I have to; you've been quite generous in the past for little profit from me.

Originally Posted by chrisb

Thirdly, I won't say published FR specs are meaningless, but you already own the most accurate and calibrated set of test gear you really need, and they're entirely portable.

Calibrated and accurate?? My ears?? LOL...
Yeah, I know... that's why I have a pair of woofers under my 'Full Range' speakers in the Fonkens. So the bass specs of FR speakers are a definite interest......

;-)

John

[Scottmoose]

Trying to compare the two graphs is of dubious value. They've been measured differently, with different equipment, are of different resolutions, with different levels of smoothing applied, the drivers are of different sizes, different efficiencies, and with completely different design priorities.

I think you may have a fundamental misunderstanding of how a driver works. If you wish to confirm the Fs of a driver, you are better off checking the impedance graph to confirm the peak is at the stated figure (in both cases it is).

[chrisb]

Originally Posted by VictoriaGuy

Hi, Chris-
Thanks for the quick reply.

I didn't say I 'believed' either of the curves, but the Alpair is something like 30dB down at 40 Hz...
IF the Alpair curve is accurate and IF one were to use the -3dB convention, then the freq response should be 100Hz to..., no? And the Fostex driver should be about the same......

I'm not criticising Mark's speakers- it's the general issue of published specs and how they are interpreted that I'm interested in. This comes up from time to time online- last time I was watching it was the AudioNirvana specs that were in question. At least Mark is apparently publishing accurate curves, which is a start.
I really don't like to waste your time and Dave's any more than I have to; you've been quite generous in the past for little profit from me.


Calibrated and accurate?? My ears?? LOL...
Yeah, I know... that's why I have a pair of woofers under my 'Full Range' speakers in the Fonkens. So the bass specs of FR speakers are a definite interest......

;-)

John

John:

accurate enough for your brain, which is wherein the calibration and signal processing occurs

if it wasn't obvious before, I frankly don't get too stressed about driver specs or math (that's for the geeks, who are in abundance here, and always eager to "educate" us ) - it's certainly been my experience that one can hear what they see - my easy solution is to avoid understanding of the technical aspects and simply let the degree of my emotional reaction decide the matter - to each his own

the offer still stands to listen to any of several pairs of the Alpairs that are compact enough to travel ( I think you might like the 12s)

[VictoriaGuy]

Originally Posted by Scottmoose

Trying to compare the two graphs is of dubious value. They've been measured differently, with different equipment, are of different resolutions, with different levels of smoothing applied, the drivers are of different sizes, different efficiencies, and with completely different design priorities.

Yes, that's true...I was comparing the graphs to the manufacturer's interpretation of their own graph, not really to each other. Do we have a 'new standard' for frequency response in the speaker world, with -30dB defining the range?

Originally Posted by Scottmoose

I think you may have a fundamental misunderstanding of how a driver works.

You are definitely correct in that! For instance, 'Full Range' to me means what my somewhat worn ears can hear at a musical performance.

John

[VictoriaGuy]

Originally Posted by chrisb

the offer still stands to listen to any of several pairs of the Alpairs that are compact enough to travel ( I think you might like the 12s)

Off-topic...
Thanks, Chris. Very kind.
I'll probably take you up on the offer, as soon as I get a couple of things cleared away here.
Are the Alpair 12s on offer 'stock' or 'eNabled' ?

I'm interested in hearing how they do - the competition here is modest - Fonkens with FE167+woofers (biamped) and AudioNirvana10s, in a pretty small room.
John

[chrisb]

BTW - to be clear (I'm not sure if there's an emoticon for the occasion), my use of the term "geek" in prior post (could have said "boffin" - but how many would get that?) is respectfully exactly the opposite of derogatory

[chrisb]

Originally Posted by VictoriaGuy

Off-topic...
Thanks, Chris. Very kind.
I'll probably take you up on the offer, as soon as I get a couple of things cleared away here.
Are the Alpair 12s on offer 'stock' or 'eNabled' ?

I'm interested in hearing how they do - the competition here is modest - Fonkens with FE167+woofers (biamped) and AudioNirvana10s, in a pretty small room.
John

This pair is EnABLed, in a rough (ie unfinished) prototype box. Small room would be perfect. Send me a PM to confirm convenient time.

[VictoriaGuy]

PM sent. Thanks!