Has anyone measured Ole Wolff speakers?

[HeadphoneManiac]

Ole Wolff's speakers have extensive documentation that looks convincing, but I haven't found any independent measurements.
Their measurements were also made on an IEC318 coupler that doesn't measure honestly under 100 hz according to ISO, so I doubt that the actual frequency response is this flat for all their models.
The roll-off on the last one is an artifact of measurement at a 10mm distance against the coupler.

 

[solderdude]

The final result in a head-/ear-phone will always be the result of porting, acoustic resistors, seal, pads etc.

Headphone brands using OW drivers (and laptop speakers) most likely will not advertise they do so.

 

[HeadphoneManiac]

The final result in a head-/ear-phone will always be the result of porting, acoustic resistors, seal, pads etc.

Let's suppose that the driver rests on the ear, protected with only a foam earpad, kind of Porta Pro-like.

Headphone brands using OW drivers (and laptop speakers) most likely will not advertise they do so.

Is it because of the competitive advantage?

 

[solderdude]

Let's suppose that the driver rests on the ear, protected with only a foam earpad, kind of Porta Pro-like.

The foam is very open and has a lot of leakage. On- and over-ears with pleather pads usually have less low frequency leakage but are very seal dependent.

Is it because of the competitive advantage?

Or they want to appear as they are not using drivers from other manufacturers.

 

[HeadphoneManiac]

The foam is very open and has a lot of leakage

But is also very transparent and doesn't affect the timbre in any way. My Porta Pro sound exactly the same with and without default foam pads on, though a bit more or less loud.

Or they want to appear as they are not using drivers from other manufacturers.

Fair point.

 

[solderdude]

But is also very transparent and doesn't affect the timbre in any way. My Porta Pro sound exactly the same with and without default foam pads on, though a bit more or less loud.

It is anything but transparent for frequencies below 3kHz and tonality differs with different thickness and pad age.
See my measurements for KSC 75

KSC75

back to Koss back to measurements home published: Jul-17-2013, updated: Apr-15-2022 NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons…

diyaudioheaven.wordpress.com

Below you can see how much the pads 'leak' below 3kHz. The bassy trace is with sealing pleather on-ear pads.

Now you can relate to the OW measurements. To tune those you have to use 'leaky' pads.

 

[HeadphoneManiac]

It is anything but transparent for frequencies below 3kHz and tonality differs with different thickness and pad age.
See my measurements for KSC 75

KSC75

back to Koss back to measurements home published: Jul-17-2013, updated: Apr-15-2022 NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons…

diyaudioheaven.wordpress.com

Below you can see how much the pads 'leak' below 3kHz. The bassy trace is with sealing pleather on-ear pads.
View attachment 414370
Now you can relate to the OW measurements. To tune those you have to use 'leaky' pads.

I didn't notice any difference in timbre between my Porta Pro with and without foam pads on, that's why I called the foam transparent.
Even thick foam pads make a difference because they increase the driver-to-ear distance, in my experience.

 

[solderdude]

The low clamping force (temple pads determining the driver distance and kind of 'hang the driver in front of the ear') and the shape of the ear will already guarantee a lot of 'leakage'.
Just put on those pleather pads and you'll hear what that leakage does for the sound

 

[isostasy]

@HeadphoneManiac I think I bought most if not all those Ole Wolff drivers in the past.

I was using the chassis which is used in all Sennheiser HD580/6xx series headphones as a base (happens to be from a HD535 in my case but they are all the same). I thought this would be a good base for DIY but this turned out not quite to be the case: it's harder to experiment with pads due to proprietary fitting and the particular diameter of the opening where the original drivers clip in makes it hard to experiment with other diameter drivers (particularly larger).

Nevertheless, I took free field measurements as I thought having some idea of the response before I put it in an earcup would give me some indicators of the kind of damping needed. Maybe erroneous but it seemed a good starting point:

This was a while ago, I didn't take notes when fitting them to the earcup and taking measurements and never got to the stage of listening. So don't want to mislead you by saying more. I did end up selling them all and just kept a pair of Peerless 50mm drivers to experiment with as it was a headache messing around with so many different drivers.

Bear in mind they all come with rear vents closed with some kind of microporous tape, some with a middle vent (like the HD6xx driver), so opening up those and playing around with damping changes the response.

n.b. some of the manufacturer datasheets on the listings here have some more measurements than what you've posted above which might help your decision.