Loudspeaker Datasheets - Why are they so Bad?

[opc]

Hi Guys,

I've spent the last few days looking through datasheets for a high output 10" midrange, and I've noticed a few things in my search:

1. Some manufacturers have incredibly pathetic datasheets for their drivers
2. Some (very few) manufacturers have extremely good datasheets for their drivers
3. Most manufacturers have mediocre datasheets for their drivers.

This got me to thinking about why we, as consumers, accept and purchase a product based on so little information? Why don't we insist that driver manufacturers run a FULL suite of standard measurements on ALL of their products? I feel the following should be the mandatory minimum:

1. Frequency Response - On Axis, 15 degrees, 30 degrees, 45 degrees, 60 degrees (IB, 1m, 2.83V, anechoic)
2. Distortion vs. frequency - 1W and 10% rated power 2nd-5th harmonic
3. TS parameters (all of them)
4. Impedance vs. Freq
5. Full mechanical drawing with all dimensions
6. Volume occupied by driver
7. Reference to all test conditions

Nice to have:

1. Klippel measuements: Le(x), Bl(x) etc...
2. Power compression
3. Suggested (and tested) alignments

I know the above is a little vague, but it at least covers the basics. For an example of a truly superb datasheet, check out what Selenium does:

http://www.jblselenium.com.br/site/a..._pdfManual.pdf

I struggle to find anything missing from the selenium datasheet other than the Klippel stuff.

In contrast, check out what PHL, Volt and AEspeakers offer:

http://www.phlaudio.com/datasheets/25_pdf/3860.pdf

Volt Loudspeakers - About Us

AE Speakers Online Store

I struggle to find anything of value in these datasheets. They've put more effort into taking pictures of the driver than actually providing useful information (in the case of Volt, they didn't even bother to take pictures). If they can't take the time to post a proper frequency response, then how on earth did they design a proper driver? If they don't have the facilities to measure their products correctly, then should they really be selling transducers to the world at large? In my mind, only one of the following two things can be true:

1. They have proper measurements but have chosen not to provide them because they aren't very good.

2. They don't have proper measurements, and therefore should not be designing drivers.

Does anyone have any suggestions about what could be done to improve the situation? Anything I've missed above that should be included?

If you know of other manufacturers with shameful datasheets, post them here so we can persuade them to change!

I'm all ears.

Cheers,
Owen

[Ron E]

Originally Posted by opc

If you know of other manufacturers with shameful datasheets, post them here so we can persuade them to change!

You are not their market - hobbyists probably account for <1% of sales what you and I think doesn't really matter.

BTW, SB Acoustics has excellent datasheets.

[Helmuth]

When they spec very precise then it can lead to claims of costumers when there are tolerances.

Also it will be easy to compare products and costumers choose the best looking spec.

You shout look in the professional corner. They spec also Thd like Beyma does. Although it depends on how you use it.

[opc]

You are not their market - hobbyists probably account for <1% of sales what you and I think doesn't really matter.

I would disagree with this, especially for the manufacturers listed. I doubt PHL or AEspeakers sell a whole lot of thier products to OEMs. Individual consumers probably make up a respectable percentage of thier portfolio either directly or indirectly through resellers like E-speakers. Manufacturers like JBL and Selenium, however, certainly can't be bothered with DIY enthusiast, but interestingly they have the best datasheets.

That is all beside the point, however, as they still need to sell the drivers to somebody, and whoever that somebody is, they will eventually need that data! It doesn't matter if you're an OEM or a guy building a box in his garage, the owness should always be on the driver manufacturer to provide proper documentation.

Regards,
Owen

[Inductor]

Yes, no data will eventually lead to a rotten egg and bad marketing.
Frd/zma's for all new drivers starting today.

[qusp]

agreed, they really are in general pretty crap, i'm at the moment searching around for a reasonably high end mid-woofer narrowed down to the ubiquitous Scanspeak 18W 8531 G00 and the AudioTechnology C-Quenze 18 H 52 17 06 SD KAP

now the C-Quenze has got one of the more useless datasheets i've seen consisting of the below and a simple FR graph without even an impedance vs frequency plot. you can customise the C-Quenze as far as magnet size, former type, sandwich cone and a midrange surround if you wish, OEMs can change a few more for a minimum order i presume. these are great drivers and the extras dont come cheap, but they hardly tell you how the standard form performs, let alone give you enough information to choose the extras. for example they make a big deal about the carbon/paper sandwich cone, but there is no data on a unit that has it vs not. hell, there isnt even any data on one that has it.

Granted they may provide all this info on request if you know the right questions to ask, but as far as the datasheet its really bad. even the physical dimensions page, for which they have a dedicated page, has very limited info.

God help anyone wanting to specify a Flex unit, however the flex units i can understand a bit, due to there being so many variables and a certain level of knowledge is assumed when buying a driver of this level. given their reputation and mainly OEM market perhaps its mostly by request. but when asked to spend nearly 1000 each on a 6.5" mid-woofer i expect some better info on the front page

the SS is somewhat better, but still not what you expect from a brand that is so widely used and by DIY as well.



C-Quenze 18 H 52 17 06 SD

Resonance frequency - fs: 40 Hz

Equivalent volume - Vas: 28,5 liter

Qms 1,8

Qes 0,39

Qts 0,32

Nominal impedance - Zn 8 Ohm

DC resistance - re: 5,6 Ohm

Effective cone area - Sd: 137 cm2

Compliance – Cms: 1,09 mm/N

Mechanical resistance – Rms: 2,04 kg/s

Moving mass – mms: 14,6 g

Inductance 1 KHz – Le: 0,13mH

Force factor – Bl: 7,3 N/A

Winding height – Hc: 17 mm

Air gap height – Hg: 6 mm

Nominal power – Pn: 150 W

Acceleration factor: 499

Efficiency – SPL: 89 dB

so that plus a FR graph is it!! WTF?

[sakis]

i can give you a direction if you like to listen ...

check the past ...go 30-40 years ago do you expect company like JBL to have 40 years ago the computing power you have in your house as we speak ? Absolutely NOT ...Expect that some of best speakers in the world manufactured with some... experience some calculation ... a lot of tests based on listening ... and generally a study based in actual principals like the above .

Can tell if hose speakers was the best in the world but be sure that the approach was the basis for today's speakers ....

Now days you have powerful software tools to tell you what to do and you need to feed them with data...so out of the blue the data needs keep increasing every day

.....Like in solid state they have powerful tools to design and simulate amplifiers ...Tools are so powerful that they may tell you how the speaker will behave if your floor is made of tiles or you may notice the changes on the software tool when you replace the tiles with carpet....

in the year 1970 was a young kid asking my father who was actually a blacksmith ( bit more advanced in the metal rectify business ) after seen the SPACE 1999 serial :

((Dad ? what is a "computer" that we see on the serial ?))
the blacksmith said :

(( don't know my son i presume though that is a machine that if you feed it crap you will get crappy results ))

Very prophet-able i think for the year 1970....

Happy regards
Sakis

[Helmuth]

If you know of other manufacturers with shameful datasheets, post them here so we can persuade them to change!

I'm all ears.

Cheers,
Owen

Did you see the data from Suprafox? The 215-2000 cost 1200 euro here is the data.
215-2000 SUPRAVOX
They even do not have a nice photo on the site. The distributers support better pictures.


May be it is just poor marketing, or a marketing choice so you can't compare till you bought one and measure it your self.

As DIY community we can measure them our self and post the driver data in a suitable topic. Here are many people with all kind of drivers at home. Would make a nice data base.

[qusp]

to be honest sakis, i'm not quite sure what direction that was intended to take me. the data i posted above is basic for even before computer modelling, not even having a frequency vs impedance plot does not give you the basic data to use as a STARTING point to see whether it will work with your amplifier or favoured crossover type, let alone modelling what effect changing the floor will have.

the physical dimensions tell you that there is 6 holes for bolting it to the baffle, but since it only shows a profile and no point of origin, it does not give you any idea where they are. its crap by any standard, but now taking into account that they themselves will have used sophisticated modelling tools to create this very high end driver and yet give us this and it becomes kinda rude in a way, given the money they want for it, rather than simply inadequate

[sakis]

Originally Posted by qusp

to be honest sakis, i'm not quite sure what direction that was intended to take me. the data i posted above is basic for even before computer modelling, not even having a frequency vs impedance plot does not give you the basic data to use as a STARTING point to see whether it will work with your amplifier or favoured crossover type, let alone modelling what effect changing the floor will have.

the physical dimensions tell you that there is 6 holes for bolting it to the baffle, but since it only shows a profile and no point of origin, it does not give you any idea where they are. its crap by any standard, but now taking into account that they themselves will have used sophisticated modelling tools to create this very high end driver and yet give us this and it becomes kinda rude in a way, given the money they want for it, rather than simply inadequate

mostly is supposed to be a joke ... point is that 2% mistake in one parameter or lie or even a printing error will make the speaker misbehave ...

to my point of view you need to listen more and compute less

simulation may be a basis for a design but the actual design cannot be only based to it

Kind regards
sakis