The Citroen Hydropneumatic Suspension - of Headphones. The $299 N90Q

[Cahudson42]

If you are one who thinks the Citroen Hydropneumatic Suspension was an elegant, system solution to the suspension problem - and are looking for your next Headphone - the N90Q 'is it' . Take a look.

But, say your opinion is: 'Those crazy French! Complicate things to no end! All you need is four coil springs and $12 shock absorbers' - might as well stop reading

A one off, likely never to be seen again, the N90Q is a genuine attempt at a complete self-contained system solution to headphone listening. Combining dynamic transducers, DAC, Class AB amp, and DSP, it provides ANC, Equalization, Crossfeed/Soundstage adjustment, and individual pinnae compensation. All for $299:
https://www.harmanaudio.com/akg/N90+Q.html

Learn more:

and more:
https://www.stereophile.com/content/akg-n90q-noise-canceling-auto-calibrating-over-ear-headphones

Problems? Yes. Durability? Don't know. Obsolete? It's 2015... But for $299? If you are a 'headphone nut' - really, take a look. At the very least you will have a great transportable system, that you can benchmark other headphone systems against.

And if you are a 'speakers only' - type, but do wonder occasionally what a decent Headphone system can sound like, here is an inexpensive way to find out.

I use mine with a USB OTG cable to a $30 LG Rebel TracFone WiFi 'DAP' running Amazon Music. That's it. All you need. $329 total. In shirt pocket.

For a unique and very enjoyable portable Headphone system.

 

[chi2]

Cool comparison and a great find. Thanks! Tried to order it to a shipito address. Either that or my Revolut credit card made them cancel my order after a few minutes .

 

[bobbooo]

If you are one who thinks the Citroen Hydropneumatic Suspension was an elegant, system solution to the suspension problem - and are looking for your next Headphone - the N90Q 'is it' . Take a look.

But, say your opinion is: 'Those crazy French! Complicate things to no end! All you need is four coil springs and $12 shock absorbers' - might as well stop reading

A one off, likely never to be seen again, the N90Q is a genuine attempt at a complete self-contained system solution to headphone listening. Combining dynamic transducers, DAC, Class AB amp, and DSP, it provides ANC, Equalization, Crossfeed/Soundstage adjustment, and individual pinnae compensation. All for $299:
https://www.harmanaudio.com/akg/N90+Q.html

Learn more:

and more:
https://www.stereophile.com/content/akg-n90q-noise-canceling-auto-calibrating-over-ear-headphones

Problems? Yes. Durability? Don't know. Obsolete? It's 2015... But for $299? If you are a 'headphone nut' - really, take a look. At the very least you will have a great transportable system, that you can benchmark other headphone systems against.

And if you are a 'speakers only' - type, but do wonder occasionally what a decent Headphone system can sound like, here is an inexpensive way to find out.

I use mine with a USB OTG cable to a $30 LG Rebel TracFone WiFi 'DAP' running Amazon Music. That's it. All you need. $329 total. In shirt pocket.

For a unique and very enjoyable portable Headphone system.

Have you tried them (via USB) using an app that bypasses the Android audio mixer (and its resampling) e.g. Neutron Player or UAPP? Because I've been having problems getting this to work with my N90Q.

 

[jhaider]

AKG’s newer efforts such as N700NC M2 are very good too. Honestly astounding at recent pricing. And they can be worn in public...

 

[Cahudson42]

Have you tried them (via USB) using an app that bypasses the Android audio mixer (and its resampling) e.g. Neutron Player or UAPP?

Sorry, I have not. I always use HD Amazon Music, and am happy with 16/44.1

Have you compared to connecting via 3.5mm? Yes, it's an extra ADC, but just maybe you might like it? And be more 'connection problem free'..

 

[symphara]

That suspension was horribly unreliable, I had a friend with one of those fancy Citroens and there was no end to his car troubles.

The headphones are interesting though.

 

[Cahudson42]

That suspension was horribly unreliable,

Yep. Often first of anything. Anyone else remember the 7mb hydraulic actuated IBM 2311 drive? And the leak cleanups?

 

[bobbooo]

AKG’s newer efforts such as N700NC M2 are very good too. Honestly astounding at recent pricing. And they can be worn in public...

Apparently the N700NC's noise cancellation isn't as good, plus it doesn't have the N90Q's 'Stage Control' spatial DSP modes that simulate 2.1 stereo speakers or 5.1 surround sound, which can actually sound quite impressive and realistic (the former more than the latter for me), depending on the source recording.

 

[Cahudson42]

spatial DSP modes that simulate 2.1 stereo speakers or 5.1 surround sound ..

Yep. Except for Chesky binaural recordings, I often use the Stereo 'studio' mode..

 

[bobbooo]

Sorry, I have not. I always use HD Amazon Music, and am happy with 16/44.1

Have you compared to connecting via 3.5mm? Yes, it's an extra ADC, but just maybe you might like it? And be more 'connection problem free'..

Well it's an extra DAC (phone) and ADC (headphone). It's hard to do a direct back and forth comparison because the USB connection only works very occasionally after multiple unplugging and replugging, but USB does seem to sound a bit clearer (that could be placebo of course). Looks like others have been having similar/related issues with their Pixel phones and USB DACs (my N90Q is often reported as 'null' when plugged in just like on that page). I'm using a Samsung though, so it seems like the problem is with the Android kernel itself. It's just a shame I can't use these excellent headphones reliably to their full potential due to Google's incompetence when it comes to audio...

 

[Cahudson42]

I'm using a Samsung though, so it seems like the problem is with the Android kernel itself.

Might be more trouble than it's worth, but have you researched what you might be able to do with a Rooted phone?

I'm thinking of your getting an inexpensive Android phone - like my $30 LG Rebel TracFone. Android 8. Really quite nice for $30...and little lost if you Brick it..:

Looks like my Rebel with it's nice replaceable battery has been superceded by the Journey - still at $30. No replaceable battery...but Android 9

https://www.amazon.com/dp/B07Y5T9X4P/

 

[bobbooo]

Might be more trouble than it's worth, but have you researched what you might be able to do with a Rooted phone?

I'm thinking of your getting an inexpensive Android phone - like my $30 LG Rebel TracFone. Android 8. Really quite nice for $30...and little lost if you Brick it..:

Looks like my Rebel with it's nice replaceable battery has been superceded by the Journey - still at $30. No replaceable battery...but Android 9

https://www.amazon.com/dp/B07Y5T9X4P/

Just tried an old phone (Samsung Galaxy S7) running Android 8 and the N90Q works perfectly over USB every time, so looks like Google introduced a bug into Android somewhere between version 9 and 11, which could rule out the LG Journey, and my S7's display is completely smashed and so unusable. I'm not a fan of having multiple devices on the go anyway, prefer to keep things streamlined with one device for everything. I'll just have to wait for Google to release a firmware fix and use the unplugging/replugging technique (it usually works eventually...) in the meantime, or just use the analogue connection if I can't be bothered with that.

 

[Cahudson42]

Narrowing down a problem is always good news! Android 8 is what comes with the LG Rebel 4. You can still find them on Amazon, but the ones I saw were all 3rd party and perhaps $50..

BTW, I've gotten use to two devices and now sort of like a dedicated phone DAP. True, the Rebel only works on WiFi, but there is always the primary phone hotspot if needed.. Good Luck!

These change by the minute, but Amazon is showing new LG Rebel 4 for $30. You have to go to 'all buying options' and when you do, one choice is $30.09 sold direct by Amazon..
https://www.amazon.com/dp/B07GBRB3SC/

 

[Ufasas]

AKG’s newer efforts such as N700NC M2 are very good too. Honestly astounding at recent pricing. And they can be worn in public...

i bought them for 89.99, -80.00 less, new, and what i can say, in all ways better than my y50bt, i will never buy another brand again for Bluetooth cans, only AKG! 4 of 4 akg cans, and never failed me

 

[Frank Dernie]

That suspension was horribly unreliable, I had a friend with one of those fancy Citroens and there was no end to his car troubles.

The headphones are interesting though.

I had a Citroen with this suspension for many years without any reliability problems.
Both Lotus and Williams used Citroen hydraulic parts in their prototype active suspension systems in the 1980s.
When Moog were complaining that Lotus' specification of the servovalve for road car production of their active suspension (which was never put in production) was impractical Peter Wright, the Chief Engineer of Lotus Engineering at the time took Moog's chief to a scrap yard near Norwich, removed one of the spool valves from an old Citroen that had been scrapped and showed him that it matched the specification he wanted.

I also have AKG N90Q but bought when they were a production item and even the discounted price was >£1000

 

[Raindog123]

I am mot very familiar with Citroen‘s suspension, but is not It similar to the one of Range Rover?

 

[Marc v E]

That suspension was horribly unreliable, I had a friend with one of those fancy Citroens and there was no end to his car troubles.

The headphones are interesting though.

My parents had quite a few citroëns. The car was like a French salad. Crispy, fresh, tasty and easy to deteriorate.

 

[Jim Matthews]

I am mot very familiar with Citroen‘s suspension, but is not It similar to the one of Range Rover?

The current Range Rover suspension uses air as a "spring" and can be tuned to allow variable rebound rates to feel sportier or softer on various road surfaces. It uses a fairly complicated feedback mechanism to control air pressure at a distribution block. It's inflated by a glorified bicycle tire pump.

The weakness of the system is the air bladders at the top of each strut. Rubber tough enough to hold pressure can be stiff and will develop fine fractures with age - leading to failures.

My own (dearly departed) A8L had a similar system and the VW parts bin controller was temperamental, prone to locking up at full height and unserviceable by local repair shops due to its model year and computing requirements.

The Citroën Hydropneumatic suspension was 50 years ahead of its time, using mineral oil as the incompressible fluid. Early versions suffered corrosion failure when standard brake fluid was substituted.

This system required the disruptive spherical reservoirs that held Nitrogen in half the chamber separated by a membrane from the mineral oil.
This dampened the system on uneven pavement.

Mercedes Benz used a similar design in their Self levelling system.

Later Citroen versions called "Hydractive" employed more complex computer controls but the earlier versions were mechanical wonders.

It was robust, supple and flexible. It was purely mechanical, with no electronic monitoring or control valves.

Poor dealer service support doomed the brand in North America, often due

 

[Loathecliff]

That suspension was horribly unreliable, I had a friend with one of those fancy Citroens and there was no end to his car troubles.

The headphones are interesting though.

Oh No It Wasn't.
I retailed Citroens for some years, DS, GS, & CX, and the suspension was probably the best engineered part of the cars.
It was a thoroughly proven system. Changing the spheres every five years was all that was required.
Though we never took potential customers over humpbacked bridges

 

[Raindog123]

I think the new[er] Citroens (or any PSA cars) are fine. I myself had a Peugeot 405 back in Europe and it was as reliable as the next car… However I do have that vivid memory - of each older Citroen DS parked on a street ’facing upward’ due to failed suspension.