New headphones for £150, advice needed.

I had the K550 for a couple of months and I didn't get on with them. I found them too lacking in bass, although that was also down to the fit not having enough clamping force and not making a good seal with the pads on your head, like an in-ear which doesn't fit properly the bass got utterly lost and it destroyed the sound for me. In the highs I found them a bit too sibilant at higher volumes - too bright. The SoundMAGIC on the other hand is one of my all time favourites! It doesn't have crazy bass but it's very deep and amazingly smooth! Frequency response wise the HP100 is one of the most flat I've seen, it's a much better contender for 'Reference' than the K550 IMO and well worth however much more it costs!

Sennheiser 558 - very comfortable, smooth and spacious sound.  Would fit your description well and sound great on my iphone 4 as well.  Well within your budget too.

I'm not sure if the OP is considering open back, I only assume that he didn't want it because the two that he was most interested in were both closed. No that I'm against Sennheiser's in any way, I'm going crazy with a couple of them right now and I have fond memories of my old 565's.

I bought the 565 after I had the 580 and the Grado 325. I dumped the 580 because the 565 gave me better presence, somewhat like the Grado but smoother. I hear a lot about the 558 and 598, so I wonder if those are more neutral like a 600, or more bassy like the main trend is today. I'd second what Edd says about the HP100, and add the HP200 as a possible alternative if open back is considered.

Don't mind open back or whatever really.

I wonder why What Hi Fi only give the soundMagic 4 out of 5 stars? That was the only thing putting me off v the AKG really, that and the fact that on Amazon there were a couple of negative reviews on the build quality. I will research the Sennheisers then also

The reviews look very good for the Sennheisers. One minus is the sound leakage which puts them out of the running unfortunately as i tend to listen most while the wife and kids are watching TV!

The soundMagics are looking favourite at the moment

I thought the HP100 was good - OK sound, but the HP200 I really love - better than any full-size Sennheiser I've owned.

 

It seems like you don't realise that open back means bad sound leaking 99% of the time, from that regard it looks like the HP100 is your better bet. Dale is right that the HP200 is a better headphone, but it's also more expensive. For the money I think the SoundMAGIC HP100 is a fantastic headphone with a very clean sound, a sparkly high end which doesn't get annoying and a bass presentation that extremely well balanced, very smooth and has some real kick too (that's really pretty rare).

I'm really baffled by WHF's scores for headphones, after giving the VModa M-80 and SoundMAGIC HP100 only 4 stars I wonder if their listening sessions are as long as thier reviews and if their reviews like headphones much at all. The HP100 is easily my favourite closed headphone for under £200, not everyone has to agree with me of course, but almost every other person who has picked up the HP100 has loved them. Admitedly it's still a very unknown headphone and manufacturer, but the owners on Head-fi are starting to grow:

http://www.head-fi.org/t/616201/soundmagic-hp100-review

Oh and as for the two negative Amazon reviews for the HP100, these werre both physical faults, not sound related ones. The fact that the HP100 has been out of stock everywhere for months is a good sign that things are being done about that. Hopefully it will be back on sale very soon. I should point out that the HP100 does come with a good 2 year warranty, just buy through an official reseller like Amazon or hifi headphones and you'll be safe anyway, but I wouldn't let any of that put you off.