I recently purchased the HD 300 Pros. Please allow me to share my thoughts on the sound quality. FYI, nowadays, I like to use just my Apple devices with the Apple lightning to 3.5mm headphone jack adapter. This is an excellent performing device with slightly better than CD quality resolution, as long as the impedance of the phones is not more than 100ohms.
Initially, when I started playing music via the phones, my initial thoughts were in agreement with others on this thread - wow, oh my goodness, the mid- and lower bass were severely over-presented in the sound spectrum. It appeared to be time-smeared which, in my opinion, increases the perception of bloat and volume. The mids and especially the highs, however, were quite pleasant and more neutral, which are big ticks for me. I personally dislike shrill sounding headphones – unlistenable after a couple of songs!
But what about the bloated bass? It sounded like the bass of large three-way floorstanding speakers in a small room – the bass was overloading and over-pressurising the room! And in this instance, the acoustics of the cup. It also doesn’t help with the use of leatherette pads as they tend to increase bass response!
Well, the good thing was that I started searching the internet for the opinion of others. I came across a very helpful review below:
https://www.reddit.com/r/headphones/comments/bd7ffr/sennheiser_hd300_pro_mini_review_and_comparison/
The author recommends a good burn-in of the phones. So I did, playing heavy rock, for 72 hours before I started serious listening again. By that time, the bass had settled significantly and the time-smearing dissipated. And the overall sound was much more relaxed. There was still more low bass than my ‘classically’ linear sounding ER4SRs and my trusty Beyer DT250 cans.
I agree with the above author that the HD 300 Pros voicing was probably based on the Harman headphone target response. The mids and highs were quite neutral, akin to the ER4SR and DT250, but it was the bass and especially the lower bass that deferred.
The run-in bass response of the HD300 Pro, and the overall sound signature, resembled more my Beyer Aventhos, which I believe are also voiced towards the Harman response.
Do note that the mids and highs of both the ‘classic’ headphone target response and the Harman response are more similar than different. Even in this current thread, jon parker noted that the mids and highs of the HD 300 Pro had some similarities to the revered classically linear sounding HD 250, which I have not had the privilege of listening to yet.
My conclusion of the matter then is that the HD 300 Pros were intentionally voiced to resemble the Harman response which is modelled after good and linear sounding speakers in a room where there is a natural rise in the bass response due to acoustic loading.
My understanding is that the ‘classic’ target response is modelled after a good sounding speaker in an anechoic chamber setting – in essence, no bass reinforcement.
I suspect that the frustration faced by some members in this thread is really in the way Sennheiser marketed the HD 300 Pros. They claim that the HD 300 Pros were voiced very closely to match the HD 250. Well, in my opinion, this is both a yes and a no! Yes, because, as alluded to earlier, the mids and highs are more similar than different. But no, because what the Harman target response defines as linear bass is different to the classic definition.
In simple terms, the HD 300 Pros is definitely linear sounding based on the Harman target response. But they have too much bass if one uses the classic target response which presumably the HD 250 was designed with.
Furthermore, if there was ever a case for the need of burn-in, then the HD 300 Pros is a most resounding yes! This is quite unfortunate because many might be turned-off from the phones before they have had a chance to be broken-in. It’s really the instance of ‘throwing the baby out of the bath water’!
So, how is the quality of bass of the HD 300 Pros? In my opinion, really quite splendid! It doesn’t bleed into the mid-range. It’s extremely fast and tight. No time-smear and integrates very well with the rest of the frequencies. Furthermore, the Harman voicing allows the cans to be used at a lower and safer sound level as you can still hear the ‘kick’ of the bass notes.
It is quite delightful to hear the quality of a present day ‘state-of-the-art’ Sennheiser headphone driver/capsule! The HD 300 Pros sound very transparent and delicate. Even at low levels, detail still comes through. I do hope though, that with continued use, the overall sound will relax even more. It’s definitely not unpleasant. But I do enjoy the alluring relaxed sound of the Beyer DT250 which is over 20 years old in design but still fantastic!!
Finally, I am very glad that Sennheiser designed the HD 300 Pros to be used for broadcast rather than just studio mastering work. This is similar to the DT250s. For studio mastering and mixing, in my understanding, you often need a headphone that has accentuated treble and bass to help the engineer pick up errors in the recording. Our human ears are most sensitive to mid-range frequencies so they don’t need accentuating. But it helps if the lows and highs are.
But if the u-shaped response is repeated in broadcast headphones, especially if the bass bleeds into the mids, and the upper-mids and highs are strident, you can be sure that it will be most uncomfortable and unpleasant for the location technician!! So, I am happy to say that the highs are quite well-tamed in the HD 300 Pros even though I still prefer the highs on the DT250s.
Thanks for reading – hope you enjoyed it. As always, my views on the HD 300 Pro are personal and subjective. They are not meant to invalidate other differing opinions. Cheers!
