HI Olivier –
I can’t make-out the scale numbers on your graphs, Can you link to bigger graphs? I’m unclear. Are you saying there’s a resonance at 150Hz that is being created by the Rycote support and/or accessories? Seems like you need another reference or “control” for your test like putting the mics in another suspension or changing the elastic-material in the Rycote suspension or even supporting the tails of the mics in foam (leaving the front of the mics open.) Your three tests have the stock Rycote suspension in common. Make sure all rigs are placed in the exact same spot. How close are the mics from the speakers?

Do you think you should include the audio in the report? If something is changing something it might be confirming for us to hear the difference as well. Also, there’s a good chance you can hear the change in frequency content when you slip the Rycote windsreen material between your ear and the speaker.

Hi Rod,

Thanks for checking and commenting. The mic rig is about 2 meters from the speakers. The 150 Hz resonance I was talking about is at the moment (to my opinion) not visible in the graphics. This freq. is derived from eq’ing and listening to my recordings so far.
You’re right about not including the suspension in the test. All the test were done in exactly the same spot with axact the same distance from the speakers.
So far what I can see in the graphic is not so much resonance but more likely a dampening effect. Especially the Mk8 is affected by this dampening.
I made a preset to correct the effect of the Rycote more or less. But when you look to the higher freq.range you can see it’s not so smooth anymore.

I’m preparing more tests with a Behringer ECM8000 test mic besides the Schoeps setup.

Hi Oliver–
I follow you about the resonance at 150 Hz being audible but not visible in your plots. If the mic suspension is responsible for the low frequency resonance, then taking the mics out of the suspension and exposing them to the same stimulus should show this. I’ve damped suspension resonance by changing the elastic material and also by lightly inserting a foam wedge between the mic and the basket. Its doubtful that the windscreen enclosure could create 150 Hz resonance because the sound waves are so long. Thick windscreen material can definitely cause loss of high frequency brightness, but the loss could be more severe. Contact me via my website if you want to share the samples with a recordist who has used a mk4/mk8 rig extensively. A comparison with an ECM8000 will require pretty loud test sound levels to avoid the influence of the 8000′s high self-noise and the suspension resonance might only show up when very high gain is used under very low sound levels. We can’t tell the effects of the suspension until we hear a comparison with the mics supported and not supported by it.

Do you use the full cover all the time (that hairy cover) – if so take it of when it’s not windy.
No 150 Hz resonace is shown in the graph.
There is a big bump of like 8 dB at about 220-300 Hz tho
– the reason for that may have been that the pink noise from the speakers had it’s strongest part in the bass (maybe below 100 Hz) and as you appearently are using directional microphones they don’t pick up the lowest part of that noise very well at a distance from the speakers due to the proximity effect – so the response shown in the graph will rise up to about 220-300 Hz, then the microphone it self act as a high pass filter.

The 150 Hz resonance is most likely cused by vibrations of some kind gets to the microphone, it may be the wind that causes vibrations. Just put the microphones on a table, then tap with your fingers on the top that table and record – that will show if the microphone picks up the vibrations.
You can probably just use high pass filter or an EQ to filter out that “resonance” anyway, since those directional microphones will probably not pick up much bass anyway, if you’re recording distant sources.

Omnidirectional microphones is much better to use for recordings like this (they are less sensitive to vibrations and pick upp the bass much better), if you’re not close to the sound source (<1 m/3 ft in free field) or only want to pick up high frequency sounds like bird song, crickets, water etc.

Btw.
I also do a lot of sound recording and I would never buy Rycote products.
I was about to do it once – then I saw the rediculous prices. When seing these graphs I'm really glad that I didn't bought any Rycote wind screens

It's easy to build own wind screens with a cage (that the micophone is inside) covered with fabric that give similar wind protection for like 1/200 of the price. The ones I use has a high frequency loss less than 1 dB up to 10 kHz, about 1,5 dB at 20 kHz and 2 dB at 35 kHz.
It's all about choose the right fabric for the cover.