http://gogiftsindia.wordpress.com/2012/04/10/5-reasons-to-buy-the-retro-handset/

I currently own a Sennheiser HD448, Superlux HD661, and a Superlux HD330. I beg to differ about the soundstage you mentioned in the review. Among the three headphones I own, the Sennheiser HD448 has the most accurate and widest soundstage. I am not saying this because I am a Sennheiser fan or anything. I applaud both brands.

The Superlux HD661 is not very musical in my opinion. It leans heavily on treble and detail thus the analytical sound signature. Among the three headphones mentioned above, the Superlux HD661 has the most detailed presentation but the narrowest soundstage. However, I do agree about the aggressiveness of the HD661 and that it gets fatiguing during long listening sessions.

The Sennheiser HD448 lacks bass extension and impact. I can always feel the lack of rumble with this headphone every time I listen to bass heavy tracks in lossless audio format. The treble is also not that sparkly either. The HD448 focuses on the mids, although it is not that detailed compared to the HD661.

For me, the most musical headphone is the Superlux HD330. It has a semi-open type design with 40mm dynamic drivers rated at 150Ohms. The sound signature is warm with excellent bass extension and detail, and an average pace when it comes to lower frequencies. The mids are slightly recessed, this is expected due to the “V” shaped frequency response graph. However, the mids are reasonably detailed and full. Treble is also excellent and crisp. I’d say it has a very detailed treble despite the slightly emphasized bass region. Soundstage for this can is in between the HD661 and HD448. It is not as wide and accurate as the HD448 but certainly has better sound imaging compared to the HD661.