I have owned both and currently have the Dynaudios, Very different sounds, though both are probably what most people, including me, would call "musical."
The Harbeths are more unfussy about associated components (they are not what I call "transparent to the source"). They have what I would describe as a "woody cello" sound. Vocals are particularly wonderful on Harbeths, having a palpable, organic quality that is hard to beat. Harbeths sound =beautiful=. Part of not being transparent to the source is less detail and resolution than many modern speakers that audiophiles favor and, as a result, Harbeths do not communicate as much about the recording venue and ambience as many other speakers. The SHL5 also has a small frequency response dip in the midrange, which helps keep them non-fatiguing across a wide range of music and gives them some added depth. The SHL5 is capable of decent bass, but in my room they always seemed a little thick and the bass lacked tunefulness. In the overall context of this speaker, its dynamics (micro and macro) are fine, but by absolute standards they are unremarkable.
The Dynaudio C1 is further along the detail, resolution and neutrality spectrum compared to the Harbeths. I've had them for more than two years and can't really identify a tonal character in this speaker; to me it sounds correctly neutral. Unfortunately, this means that it's possible for the speaker to sound too thin if the system and room take it that way. But I don't want to overstate that because I don't think it's a big problem. Bass on the C1 is not only surprising for the size of the speaker, it is outright wonderful. In my experience, it goes deeper, has more impact and is more tuneful than the Harbeths. The speaker is ported, but its bass is very much like a sealed box design, which I love. The Dynaudios play louder and have more and better dynamics than the Harbeths. The Esotar2 tweeter is exceptional, and you will hear extension and treble dynamics you won't from most other speakers.
In my room, I'd like a little more lower midrange from the Dynaudios. They are not intrinsically beautiful sounding in the way the Harbeths are, but I believe they are more accurate and multi-purpose, if that matters to you. I like both and while I no longer have the those Harbeths, I do have a pair of JM Reynaud Duets, which I sometimes swap in to spell the Dynaudios. The Duets have some of that Harbeth sound but with a different twist and make for a nice change of pace.
Neither speaker is a world-beater at low volume, but neither sucks at low volume either. The Dynaudios definitely want more power. I have recently been driving them with an Ayre integrated at 60wpc, and it works, but more would be better. Harbeths are easier. This might be useful: The Nuforce Ref 9v2 SE sounded wonderful with Harbeth and not good at all with the Dynaudios. Can't tell you why.
I hope this is helpful.
The Harbeths are more unfussy about associated components (they are not what I call "transparent to the source"). They have what I would describe as a "woody cello" sound. Vocals are particularly wonderful on Harbeths, having a palpable, organic quality that is hard to beat. Harbeths sound =beautiful=. Part of not being transparent to the source is less detail and resolution than many modern speakers that audiophiles favor and, as a result, Harbeths do not communicate as much about the recording venue and ambience as many other speakers. The SHL5 also has a small frequency response dip in the midrange, which helps keep them non-fatiguing across a wide range of music and gives them some added depth. The SHL5 is capable of decent bass, but in my room they always seemed a little thick and the bass lacked tunefulness. In the overall context of this speaker, its dynamics (micro and macro) are fine, but by absolute standards they are unremarkable.
The Dynaudio C1 is further along the detail, resolution and neutrality spectrum compared to the Harbeths. I've had them for more than two years and can't really identify a tonal character in this speaker; to me it sounds correctly neutral. Unfortunately, this means that it's possible for the speaker to sound too thin if the system and room take it that way. But I don't want to overstate that because I don't think it's a big problem. Bass on the C1 is not only surprising for the size of the speaker, it is outright wonderful. In my experience, it goes deeper, has more impact and is more tuneful than the Harbeths. The speaker is ported, but its bass is very much like a sealed box design, which I love. The Dynaudios play louder and have more and better dynamics than the Harbeths. The Esotar2 tweeter is exceptional, and you will hear extension and treble dynamics you won't from most other speakers.
In my room, I'd like a little more lower midrange from the Dynaudios. They are not intrinsically beautiful sounding in the way the Harbeths are, but I believe they are more accurate and multi-purpose, if that matters to you. I like both and while I no longer have the those Harbeths, I do have a pair of JM Reynaud Duets, which I sometimes swap in to spell the Dynaudios. The Duets have some of that Harbeth sound but with a different twist and make for a nice change of pace.
Neither speaker is a world-beater at low volume, but neither sucks at low volume either. The Dynaudios definitely want more power. I have recently been driving them with an Ayre integrated at 60wpc, and it works, but more would be better. Harbeths are easier. This might be useful: The Nuforce Ref 9v2 SE sounded wonderful with Harbeth and not good at all with the Dynaudios. Can't tell you why.
I hope this is helpful.