Sennheiser PXC-450 - Should I buy a headphone amp?

[ollyspalding76]

I recently purchased the Sennheiser PXC-450 to replace a pair of Sennheiser HD 25. Clearly they are a very different proposition and whilst the former pair delivered a robust sound, I never found the fit comfortable for longer periods of listening.

The PXC-450s were the closest match to my usage - travel, commuting, home and office listening. Of the noise-cancelling 'phones they seemed the best all-round choice. However, being closed-back I am finding the bass a little inconsistent, sometimes it seems quite tight and lacks depth.

Is it worth investing some money into a budget headphone amplifier (I'm thinking the Project Head Box 2 as I don't really want to spend a fortune). Will it make a noticeable difference, particularly to bass response?

I listen to a lot of electronic music, so my personal preference is more bass-heavy than most, but at the same time I don't want to annoy fellow travellers with an open-back set of cans.

As an aside, is it possible that more expensive phones tend to reveal more flaws in the source recording? I listen to a fair amount of downloaded music and I can much more clearly detect the harshness in a 192kbps song versus 320Kbps with these phones versus the HD 25's. Is there any truth in high-end phones being less forgiving?

Thanks for your help!

[extremelydodgy]

You didn't mention what you were using it out of. The effective, at-ear output of the PXC's might be less than the HD25's - so some degree of amplification, or buying your portables outside of the European 100db directive (i.e. ebay/etc a US-sourced player) might help.


The HD25 is quite sibilant and the problem might have been that when you're hearing rough-edged artifacts in the sound before it might have been masked by the phone's own sibilance. Having said that, it is possible to tell the difference between 192K and 320K on even an HD25 - so perhaps the tonality of the PXC is agreeing with you better.


The HD25 is also a reasonably impactful phone in terms of bass, while online reviews (I'm not big on noise cancellers so haven't owned as many of them as I have other types) seem to indicate that the PXC's can be bass light. The lack of bass may just be how they are supposed to be.

[chrisgeary]

The PXC450s are indeed bass-light when the noise cancelling circuitry is on. Turn it off, though, and you will be in a world of bass and indeed sub-bass nirvana. In fact, its a little too much.

Do you wear glasses? The 450s don't seal well around my spectacle arms but this break is enough to tame the slight over exuberant bass response.

Tight they most definitely are. Lacking depth, yes only when using the noise cancelling. They easily reach to 18hz (measured by graphing the input source on a PC) so depth is not an issue without noise cancelling enabled.

You should find them very smooth in the treble compared to the HD25s. I posted a detailed review of them against the Bose QC2s here

Whilst they would probably benefit from a headphone amp, I've never felt the need. They mostly benefit from turning the bass down on the source when not using NC!

[ollyspalding76]

Thanks for the advice!

I'm sure I didn't imagine it - having experimented with noise-cancelling in normal and bypass mode when I first received the 450s and heard limited difference - but with the noise-cancelling off after a couple of days of use they really seem to have come to life.

It would seem that the more expensive the headphone the longer it takes to bed in? It wasn't the case for the HD25s.

In normal mode the bass is full and rich (and can be toned down when it overpowers, which is not often for my tastes!) and the treble is far smoother and more comfortable for long listening than the HDs.

I'm still weighing up whether a headphone amp is worth the investment or whether different hardware upgrades are in order. Most often I connect my headphones to my PC via the Logitech Z-2300 headphone jack. In this respect I wonder if upgrading my soundcard would be more prudent (e.g. an M-Audio unit with RCA connections).

I also have a Denon compact hi-fi, which is where I was considering on adding the headphone amp. Being new to 'headfi' I'm still quite unclear as to the level of improvement and how much to spend for an appreciable difference. I read through the advice on forums here and it seems to divide opinion unless you're spending serious cash.

As an aside, I purchased a FiiO E5 for my iPod Nano and have found it to be £20 thoroughly well spent. Essentially a mini amp (the more expensive options are just too big) it seems to do a really good job of boosting the sound, bass performance, without upsetting signal clarity. I thoroughly recommend it for anyone wishing to extract that bit more from their MP3 player without getting too immersed in the audiophile debate.