Ultrasone PRO900 - Page 6

Unfortunately, ultrapaul has shown to be slightly less than complete or accurate in his statements. They are little more than corporate marketing copy. I would not rely soley on his posted content for any real "meat" (again, unfortunately).

We already have contradictory info from an (allegedly) different leg of Ultrasone that the Pro900's use the same existing driver as in the Pro750 & E9.

Well, the impedance is different between Pro750/900 and E9, so are they really the same driver in the first place? Everybody seems to say so, but specs are different (apart from both being 40mm titanium coated).

The PROLines has a network inside for protection purposes, and that increase the impedance a little bit...But they use exactly the same driver as the Edition, I owned both, opened both, and have seen both drivers in front of me side by side...measured them and they are the same, about the 900, if the freq responce is difference (higher in this case) I'm assuming it is not the same driver, as you can not increase the freq response with a network...

If they measured it after they put the drivers in the casings, then it would.

See, you are assuming that they measured the frequency response after the fact that they already put diode boards on the drivers. If you apply the same logic to the casing and assume that they were measured after they put the drivers in the new casing then it makes perfect sense that they could have different response even from the same drivers because different casings have vast influence to the range of response as well as characteristics of it.

The specs posted for the headphones usually are the specs of the headphones as a whole product, measured with a dummy head, for the freq response, and with the lead on the cable supplied as stock, why do you think the curves are different?

The casing may modify the shape of the curve, but they can not increase the extension of the freq response, in the best case, decrease it....
It will be really unlikely to measure the drivers outside the casings, to post specs for heapdhones, as this will false the readings, freq response specially the bass and the curves will change in open air, and inside the casings.

BTW as I stated, that personally I have measured both, without diodes, and they measured identical...Also Evan the former engineer from Ultrasone told me the same, no need to doubt neither...they are the same drivers...if you want to keep on arguing, that is up ot you, for me there is absolutely no doubt at all...

The PROLines have a network that increases impedance by 10 Ohms?!!! If you add impedance in series with the headphones, you're effectively increasing the output impedance of your amplifier by that amount, meaning that even if your amp has an output impedance of almost 0 Ohms, with the ultrasones it will be like an amp with an output impedance of ~10 Ohms, and since the impedance of the drivers is ~30 ohms, you will have a damping factor of about 3. This can also affect frequency response if the impedance of either the network or the driver varies with frequency, which could negatively affect sound quality (though, this wouldn't change the absolute range of the headphones' frequency response, so it couldn't be responsible for the PRO 900's wider response spec). If I bought a PROLine, I'd probably have to open it up and remove that protection network if it really is responsible for an additional 10 Ohms of impedance.

umm guys, back to point at gawkin at the new headphone.

Ultrasone's 'radiation reducing' Pro 900 headphones | musicradar.com

priced at $600, but i don't know if ultrasone generally sell for cheaper than their RRP. i hope not, otherwise i will dearly be tempted. they do look like they are supposed to bridge the gap between the current line and ed9.

edit: also, the article says "new pro series". so perhaps others to be expected in this new series.

That could be a posibility in the case fo the PROlines, but the Edition 9 has absolutelly nothing attached, and is rated 8Hz-35KHz as well, so if the new 900 is 6Hz-42KHz, to me they are not the same drivers, unless measured differently, or under completelly different conditions....

The network is IIRC a couple of diodes only, nothing else, to limit the current and avoid to blow the drivers by any abuse/misuse, in the studio, the main purpose and use of them...

Guys I'm not the designer, and I'm not sure what the effect on the total impedance is, and what exactly they were looking for, and what kind are exactly those diodes (or maybe they are other component, but they looked like diodes to me) but all I can say is that while I measured the drivers with nothing attached, they measured identical, around 30 ohms....here is a picture of the inside of a PROLine and of the Edition 9...If you look closely also the ports on the back of the driver are tuned differently as you can see, they cover different holes...etc...

Sovkiller, analogbox wasn't saying that the presence of casing could increase the frequency response of the drivers. He was saying that if the freqency responses of both the PRO900 and the Edition 9 were measured with the drivers installed in the headphones, the differences in casing could be responsible for the difference in frequency response between the Edition 9 and the PRO 900, i.e. the Edition 9's housing decreases frequency response more than the PRO 900's does.

Ultrasone's press release clearly states that the PRO 900 uses a NEW driver, but Ultrasone has also said to several of us that the PRO 900 uses the same driver as the Edition 9 and the others, so we have a contradiction. To get the final word from Ultrasone on this, we would need them to explain why we got two contradictory stories and which of them is correct. But you say you've measured both drivers, and confirmed that they are the same? Did you take the drivers out of the casing to measure them? Because that would be the only way to determine whether or not they are the same. If you've done that, I'm guessing you've also listened to them? Any impressions?

Edit: I see from your above post (which you posted while I was typing this one) that you were just saying that the current PROLines have the same driver as the Edition 9, not that the PRO 900 did. That was where the mixup was. I believe analogbox was talking about the PRO 900, not the PROLines.

Thanks for the pics.

Sovkiller, it looks like those diodes are in parallel with the drivers on the PROLines? Now I'm confused. If they're in parallel, they could only subtract impedance, not add it (if it does anything at all, and it's unlikely that it does much). So what's responsible for the additional impedance in the PROLine? Have you by chance measured the impedance of the PROLine with the diodes in place and confirmed that it is different from the Edition 9's, and not just listed by the manufacturer as being different? I just don't know what would add impedance. And yeah, thanks for the pics. Interesting stuff.

That could be possible, and maybe I misunderstood his post, sorry, but think about that, what could be the use in limiting the freq response in a top of the line headphone?... ...The Edition 7 that was their more expensive creation and it has the same internals as the 9...

I have not heard the new 900 yet, but I have heard the PROLines and the Editions, and indeed both sound completelly different, it is like they are two completelly different sounding heapdhones, but they way both are mounted in the cups are completelly different as well, along with cup shape, padding etc...

I would like to hear the new 900, but honestly, I doubt that they will be more resolving than the Edition 9, in that regard I have not heard any dynamic hepadhones that does yet. The way the drivers were mounted in the Edition was pretty open to me, they are almost completelly exposed, and as per their same claims due ot the S-logic technology, they will not mount any driver completelly exposed, and IMO going any further than the exposure in the Editions will be practically to completelly expose them, so no S-Logic then?

IMO they could be the same drivers but the posted specs for some reason are wrong, for either one...a typo, a mistake who knows??? Or they are indeed different drivers, one of the two options...But IMO they can not be the same drivers with that so different specs...

Sorry but I never measured them with the diodes on, but IIRC, according to Evan those were the responsible for the difference in impedance, I just measured them clean....But maybe the wire is soldered in a floating tab, and from there to the coil tab, and they are in series, not sure???

But thinking twice you are right, if they are on top, does anybody had any PROLine on hand that could measure them??? That will expose if they were indeed 40 ohms....

It does not make sense to me to have diodes in series. Diodes have a threshold voltage before they pass any current through (about 0.7V for silicon). In parallel they could act to shortcut the amp if the voltage to prevent the driver blowing.

However, given there are two I don't really understand the configuration. If the two diodes are in series, that would double the threshold voltage but act only one way.

(My electronics experience is way back, I might be talking complete bollocks too.)

They are soldered in opposite direction, that is for sure....