RH-300

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published: Apr-8-2017, updated Mar-22-2020

NO SMOOTHING is applied to the shown plots. Most measurement sites have some smoothing applied which ‘irons flat’ sharp peaks and ‘wiggles’. I do not use smoothing because some info about sound quality is lost when plots are smoothed.

Aside from a small correction of the microphone itself also some correction in the lowest frequencies is applied to the plots to compensate for the perceived loss of bass when using headphones. This is described HERE in more detail.
A ‘horizontal‘ frequency response curve on the shown frequency response plots on this website thus indicates a perceived ‘flat’ tonal signature.

ALL measurements are made with a good SEAL on a flatbed measurement rig.
The shape of your head, bone structure, pad size, pad ‘softness,  (compliance), hair or no hair and or wearing glasses may (drastically) change the frequency response of some headphones, so… your personal experience may differ substantially from these plots.

Frequency response (tonal balance) is the most sound-determining aspect of headphones. A horizontal line shows audible neutral response in the plots on this website. Deviations in different severities at different frequency bands have an effect on the sound character.
The bigger the deviation the stronger the effect.
Below an aid to help determining the sound character of headphones with relation to the frequency response.

Roland RH-300

The Roland RH-300 is not a well known headphone in the Hi-Fi scene. It is targeted at home recording and musicians.
The headphone is quite sturdy and looks nice. The headband is soft and padded. The pads are pleather and reasonably soft and compliant.
The clamping force is excellent, not too tight, not too loose so a good seal is possible.
The cups can be rotated over almost 360 degrees. Swivel is small, about 10 degrees but sufficient. Height can be adjusted over 35mm so will fit larger heads as well.

Comfort is quite high but the ears do get warm after some time and the pads somewhat sticky.
Isolation is good. Not stellar but somewhat better than most other sealed headphone.
The cable is quite long (3.5 meters) and has a 6.3mm TRS jack. The 6.3mm part can be screwed off and then a 3.5mm TRS jack appears. Plug looks nice. The cable is supple, feels nice and sturdy and is not microphonic !

There is a 45mm driver with an impedance around 32Ω. It has a quite high efficiency (101dB @ 1mW) so plays quite loud from portable gear. The driver can handle a staggering 1.6W so will be hard to destroy with most amps.

specifications:

Type: On-ear, closed
Usage: Home, Studio
Isolation: decent (closed headphone)
Driver type: dynamic
Pads: replaceable, pleather
Collapsible: no
Headphone connector:  fixed
Cable entry: left sided.
Cable: 3.5m terminated in 6.3mm TRS + 3.5mm adapter
Driver size: ø 45mm
Nom. power rating: 1.6W
Max. voltage: 7.2V
Max. current: 225mA
Max. S.P.L.: 131dB
Impedance: 32Ω
Efficiency: 101dB @ 1mW
Sensitivity: 116dB @ 1V
Weight: 285 g. (incl. cord)
Colour: black with grey accents
Clamping force: medium/low
Accessories: 6.3mm adapter, pouch

Sound description:

This headphone can be used quite well for Hi-Fi listening but isn’t totally neutral.
The character is warm with a deep and not exaggerated bass.
Bass quality and mids is quite good. The area where it lacks is ‘clarity/presence’.
When listening to this headphone exclusively for a longer period this isn’t really evident and sounds reasonably ‘neutral’ with nice bass, mids and sparkling but not exaggerated treble.
When coming from better headphones that do not lack presence the headphone sounds a bit dull and muffled but the brain easily adjusts (a bit like the NightHawk in that aspect, but the NH is way more ‘extreme’. The treble sounds a bit subdued. It doesn’t sound rolled-off but also isn’t very bright nor super detailed.
The only areas where this headphone thus is lacking is clarity/presence and treble quality. The treble tonality is a bit off and not refined yet smooth and soft.
Because of this tonal character it can be listened to at higher SPL and for longer periods.

Below the frequency response of the Roland RH-300 (Right, Left)

The bass extension and linearity is excellent from <10Hz to 1kHz with a slight emphasis on the lows. Above 1kHz it doesn’t look as nice anymore. The 3.5kHz ‘dip’ is responsible for the lack of presence/clarity. This dip is wider and deeper than with most other headphones I measured. The treble from 9kHz to 18kHz is not elevated and of the right level. The fact that above 4kHz the treble has lots of peaks and dips usually is an indicator of diminished resolution in the treble. The frequency response shown above has a high correlation to how it sounds.

The headphone is specified from 10Hz to 25kHz (probably -20dB) but it looks more like <10Hz to 18kHz with a sizeable ‘dip’ around 3.5kHz.

Below the distortion plot of the left channel.

This is quite good. The distortion between 300Hz and 6kHz is about -55dB (around 0.18%). Even the distortion in the lows is quite good. The driver appears to be well damped. No high distortion peaks in the treble.

Below the CSD of the RH-300 (Right and Left channel superimposed)

The CSD does not show any resonances that may be problematic. The dip around 3.5kHz is quite obvious. Around 4kHz there is a short lived resonance so it looks like the driver may have some break-up problems.

The spectrum plot below (left channel) also shows a well damped driver. Perhaps around 1.5kHz some small lingering.

Below the impulse response of the left driver.

It shows the leading edge is a lot smaller (-10dB) compared to the rest. Bass extension is excellent, almost exemplary.

Lets have closer look at the driver itself.

When the pads are removed the driver appears to be angled at around 10 degrees. Because of this there is slightly more room for the Pinnae as the baffle is recessed there. The pad itself is only 16mm thick so the extra 6mm at the rear at the head is certainly welcome.
The height of the hole in the pad is 55mm, the width 35mm. The holes in the baffle don’t seem to be doing much. Most likely because the pads seal them.
Below the effect of sealing all front ports, sealing only bottom front ports and sealing the rear ports (behind the yoke) versus stock. As the headphone has been reseated small differences may well come from a slightly different placement on the test rig. Sealing the rear ports lowered the amount of bass slightly.

The rear of the driver is quite interesting.
There is a small chamber around the driver which has foam inside. A small hole is there to let the wiring out/in.
It would appear that the designers didn’t just mount a driver inside and called it a day.
It may well explain the well (and not overly) damped behavior.

On the left the driver becomes visible when the cover is lifted. The driver itself also has proper damping applied. The damping paper in one of the holes also has a hole in it so here too it seems the driver is carefully tuned for proper bass reproduction.

The biggest issue this otherwise decent headphone has is the lack of clarity and treble quality.

Some experiments with various pads that fit this headphone have been made. One of the noteworthy and easily obtainable pads that have a positive influence on the sound and measurements turned out to be the Brainwavz Hybrid HM5 pads.
Other Brainwavz pads as well as many others I tried did change the tonal balance but not for the better. ONLY the Hybrid HM5 pads gave an improvement.
It does come at a small cost in efficiency though. The efficiency is lowered by a good 7dB when these pads are applied which is quite audible and requires a few extra steps of the volume control.

Below the difference in output level is quite obvious. The exact same signal level is applied (to get around 90dB SPL at 1kHz with the original pads).
Original pads, Brainwavz Hybrid HM5 pads.

The level difference is obvious but the benefits these pads provide are also plain to see.
Between 20Hz and 1kHz the response is excellent. The 3kHz dip is still present but instead of being 20dB with the original pads the dip is 5dB less deep and less wide. Also the treble area between 4kHz and 18kHz is much more linear and of proper level.
The slight peak around 15kHz is not objectionable but is easily lowered by applying on 1ply of a sheet of 3-ply toilet paper in front of the driver.

Below the difference in tonal balance becomes more obvious when the level differences at 1kHz are removed. The HM5 pads have a much better frequency response than the original pads.

Below the frequency response of the RH-300 fitted with Hybrid HM5 pads and one ply of toilet paper between the pads and the driver. (Left, Right)

The ‘clarity/presence’ dip around 3kHz is much smaller in depth and width. The treble quality also has significantly improved. Less peaks and dips and quite linear between 4kHz and 18kHz.

The impedance of this headphone doesn’t vary much. I don’t post impedance plots as the audible effect impedance has depends on the output resistance of the amplifier.
Instead I show the effect a 120 Ohm output impedance has on the tonal balance.
I haven’t seen any ‘damping-factor’ effects. Below the effect on the tonal balance when matched for output level with a 0.2Ω and 120Ω output resistance.

No audible changes in tonal balance nor in ‘speed’ or ‘damping’ in the bass. Of course there is a considerable drop in loudness (-10.5dB) when connected to a 120Ω amplifier which is likely to change parameters like amplifier distortion and amplifier noise levels as well as the effects of halving the loudness.

Then there is the effect seal has on the tonal balance. For this headphone the effect of a slightly broken seal (glasses) is already profound. Even more when the seal is broken with a 6.3mm TRS plug versus a perfect seal. To find out if the bass response is good simply press earcups a bit more onto your head. When bass levels change the seal is partly broken when little change is heard the seal is good.

Below the distortion plot of the modified RH-300 (Left channel)

Distortion in the bass is a bit higher but not reaching problematic levels and remains below 1% which is very good. Between 300Hz and 10kHz the distortion remains below 0.15% which is excellent.

Below the CSD of the modified RH-300

This is quite decent and does not show any problematic behavior.

Below the spectrum plot.

No problematic things here either. Some improvements over stock pads.

Below the impulse response plot of the RH-300 fitted with HM5 pads.

The ‘attack’ is much improved (5dB higher in initial amplitude). Bass response is still great.

The square-wave response and impulse response plots also show some considerable changes.

Below the 40Hz, 440Hz and 100us impulse plots. On the left with stock pads on the right with the HM5 hybrid pads.

The 40Hz response of the stock pads is in one word excellent. With HM5 pads it still is good but slightly less in bass linearity.
The 440Hz square-wave response of the stock pads show the lack of clarity by the rising and falling edges to not be ‘sharp’ but being closer to a sine-wave. The HM5 pads response is much closer to that of the applied signal.
The 100μs impulse response of the original shows the poor high frequency response.
The red line should reach the same level as the green stimulus, instead the membrane barely moves and the following resonance is even slightly higher in amplitude.
This shows the below par treble response of this headphone most clearly.
With HM5 pads the impulse response is almost reaching the desired level. The ‘double pulse’ is most likely part of the evidence that despite the pads giving a more than substantial improvement in treble quality and clarity/presence the treble still lacks somewhat when compared to the better headphones.

All in all the improvement in overall sound quality with the Brainwavz HM5 hybrid pads is well worth the extra investment.
On top of the sound improving noticeably the comfort is also MUCH improved. The pads are softer, allow for more room for the ears and aren’t nearly as ‘warm’ to the ears.
The sound is much more realistic and while still slightly lacking in clarity/presence it isn’t nearly as obvious. Bass and mids are still of the same high quality. The treble also has improved substantially but is still somewhat behind compared to the better Hi-Fi headphones.
With the Brainwavz pads this headphone is highly recommended for those loving a full sound with deep bass, slightly laid back sound and present with a good and present treble.

Positives:

• build quality
• comfort (especially with Brainwavz pads)
• cable low in microphonics and not heavy nor flimsy yet supple.
• Deep but not accentuated bass of high quality
• high efficiency (can be easily driven by phones etc.)
• 6.3 + 3.5mm TRS jack
• Tonal balance (with Brainwavz pads) although still slightly lacking in clarity.

Less positive:

• cable length (3.5meter)
• lacks clarity/presence (much improved with Brainwavz pads)
• treble/detailing is somewhat less (improves with Brainwavz pads)
• Slightly boring design and sound
• sticky/warm pads (less so with brainwavz pads)

I can recommend this headphone for Hi-Fi listening when the Brainwavz pads are fitted. The sound is balanced and ‘polite’ just slightly lacking presence/clarity.

Without those pads the headphone can still be enjoyable to those who like full bass (too little for bass heads) and a warm sound with soft treble.

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