C.Crane Senta-Forty headphone review

May 28, 2009
I found a pair of headphones now serving double-duty as BOTH a hi-fidelity and SWL application.

So I tried the C.Crane Senta-Forty headphones. Rather than merely repeat other reviews, I'll provide a little different info.

Yes, fit and finish are great for this price range. No, they are not Sony MDR's. But close, yet different. Superbly lightweight, flexible on-ear, and comfortable. Like wearing a pair of potato-chips. And, like my RadioSport communications phones, the cord is removable, which means that if you stand on the cord at a table and rise up, you may not be tearing your ears off. Great. Lay-Flat design appreciated. Cloth covered cord is a nice touch. At only 4 feet long, it won't tangle on the desk, but many might want the extension accessory for the lay back on the couch and drift away type of operation.

It's way beyond the typical consumer level quality at this price range, although once you hear them, you'll probably want to treat them with a little respect, rather than bang them around or toss them into the bottom of a fly-away case. Don't do that. Comes with a nice flexible case.

I got them primarily for my CCrane Pocket and 2E desktop radios, and I wasn't disappointed. Later, I tried them on an Alinco R8T, and also my Kenwood TS-590S.

Frequency response is a tasteful set of band groupings which you can see on the box. Although not labeled, I clearly see bass/vocal, presence, definition, and sparkle band groupings. Tastefully applied.

Long term - while the low-end shows a -6dB rolloff, with many formats over-emphasizing the bass, or a station's own EQ / compander thumping away on the low end, I would have preferred a -12db rolloff personally. Of course my local classical station, and fm talk has it's EQ together, and the phones sound great to me. A slight reduction of bass on the 2E radio solves any over-eq'd bass very quickly.

The wooden enclosures help provide a non-resonant transparency that I enjoy. (If you don't believe me, see the review of the Target SSB receiver where I build a top enclosure out of cardboard on purpose!)

COMM SPEAKER? You gotta' be kidding - but no.

On a lark I tried the Senta-Forty's both on my Alinco and Kenwood TS-590S. Even though the phones are 32 ohm impedance, for some reason the drivers seem to agree with the receivers audio amps fine enough not to sit in the hissy non-linear region at the crack of opening the pot up. Surprising.

Normally when I introduce a pair of higher impedance phones to the Kenwood, the quick fix to kill the hiss is to use an inline attenuator just a little to dampen the mismatched impedance, AND the usual over-sensitivity of the headphone transducers.

The Senta-Forty's were basically plug an play.

I truly expected the full frequency response of the Senta's to be totally unusable with the receivers, even on AM, but I was surprised. Note that the Kenwood has it's own RX-equalizer settings, (which I left at flat or default), and the Alinco has none.

Yes, there is a *slight* amount of unnecessary high-end response, but all it took was a slight adjustment of the Kenwood's filtering, or a tiny tweak of the IF Shift on the Alinco to tame it real quick.

I'm still getting used to the "sound" of usable hi-fi headphones on the Alinco and Kenwood, which is normally a no-go from anybody's standpoint.

Rather than just make up stuff, I like the sound of AM/SSB/CW, although it is different from the decades of comm phones I'm used to (Kenwood HS-5's, etc), but weird stuff like noise is not so harsh. Hi-Fi noise? Now you know I'm making this up right - NO. Rolling across my utility line buzzsaws on various frequencies didn't make my ears bleed.

In the end what all my hot-air means is that the Senta-Forty's frequency response and drivers seem to be useful (with some small tweaks to bass/treble depending on content) so that there is no long-term listener fatigue, and surprisingly good on the Kenwood and Alinco, which I didn't expect.

Field-day, yeah probably not. But for in-house usage without a noisy household going nuts all around you - by all means.

Reviews of headphones are like reviews of shoes - no one size fits all. For me, these fit both physically and *sonically* well for my SWL / Broadcast / Amateur operations.
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May 28, 2009
Noise reduction analysis -

While unfair to do musical headphone listening comparisons to shortwave listening, I think the reason that noise on HF seems to be a bit more tolerable has to not only to do with the frequency response, but also the transient response, reducing the "in your face" details.

That's not really necessary for broadcast / swl'ing, but may have a distinction musically.

For example, the Outlaw's "Green Grass and High Tides" is two totally different songs depending on whether you are using the Senta-Forty's, or using a pair of good buds. Classical isn't the only thing I listen to. Yeah, I hear the jokes now. :)

With the Senta-Forty's, there may be a lack of immediate transient response when listening, that places you in the audience, or away from the source somewhat. But now it's easy to miss *musical* details.

With the buds, I've got a really tight bass-line, and the transient immediacy takes me from the audience onto the stage. My ears seem to be about a foot away from the guitar frets. Every attack, sustain, decay, vibrato etc is heard distinctly. It can force a grown man to break out into air-guitar.

That sounds great, but for long-term listening on shortwave, that might be too much transient response, and I was surprised how my local buzzsaw qrm didn't make me yelp when I rolled the vfo across it with the Senta's. The buds on shortwave didn't last 5 minutes before putting them back on the pocket radio.

We'll see if I can live with that long term. It's just weird getting used to it on HF.
Sep 8, 2006
Stockholm, Sweden
Good to know is also that all speakers, headphones and earbuds have different sensitivity expressed in dB. Earbuds that have a rating higher than 100dB are usually too sensitive and you'll hear a background hiss even when the volume are fully turned down on a scanner or communication receiver. An inline volume control on the cable are then usefull to reduce the level until no hiss are heard. If you choose headphones or earbuds that have 97dB or lower sensitivity you in most cases don't need the extra inline volume control.

For HiFi you cannot use that inline volume control as it will introduce a high impedance between amplifier output and the headphone/earbud. The amplifier will then not have full control of the signal as the varying impedance of the headphones/earbuds will give different signal level together with the fixed impedance of the inline volume control and it will resonate and ring without the extreamly low impedance of the amplifier to dampening the unwanted phenomenon.

The outher ear, that are different between persons, are coloring the sound as it collects the sound waves and directs it in to the ear canal. Using earbuds change all that and that's why no one use them for HiFi listening and are just for uncritical and undisturbed listening at the bus or subway or when working in the garden. Never use earbuds in traffic, walking or cycling, as you then are isolated from the world and do not hear or notice other pedestrians or cyclist coming up from behind. Never look down at your phone more than a second or two while surrounded by pedestrians, cyclist or vehicles.

May 28, 2009
Ubbe - that's great info. You'll find this comparison interesting however:

Yaesu YH-77STA comm headphones vs C.Crane Senta-Forty shootout:

Yaesu sensitivity: 103 db/mw
C.Crane sensitivity: 110db / mw

Both are rated at 35Z impedance

Kenwood 590S looks for 8 ohm impedance for headphone, so there is a natural mismatch along with sensitivity issues

Yaesu phones on Kenwood requires a slight touch on external volume control to kill the hiss.

C.Crane Senta's on Kenwood - no hiss. Just plug it in.

Both of the phones have frequency response usually larger than what's desired for SSB. But this is interesting:

With the Yaesu phones, I always use a lowpass and highpass filter, ie about 300 to 3K to make ssb listenable.

With the Senta's, the whole response seems to have much more fidelity in the vocal range, and the low end rumble of band noise is really not objectionable. At the high end above 3K, yeah I'll *sometimes* do a low pass rolloff above about 1.5k, but depending on the background it doesn't always seem as necessary.

I think there may be something going on with the Senta's that go beyond just the transducers. Maybe some additional sound-shaping circuitry going on inside. I'm half tempted to cut one open. :)

It didn't take long for me when doing the A/B comparison between the Yaesu 77's and the Senta-Forty's -- The C.Crane phones win hands down. It's not even a guessing game - just *blam* and you know it.
May 28, 2009
C.Crane Senta's on Kenwood - no hiss. Just plug it in.
Update - I had to dig really deep on the Senta's, but unless you go looking for it, one wouldn't notice. But yes, there is a *tiny* amount of hiss on the Kenwood 590s.

So I used an external little "volbox" cranked in just a tad.

Ubbe - great info about the 97db sensitivity tipping point. Even though for most, the hiss is inaudible on the Senta's when attached to the Kenwood, I started looking for what you were describing further up the volume chain and found what you described there a little bit too. I put the volbox attenuator inline.

From what I understand, the recent "SG" model of the Kenwood is supposed to be a bit more tolerant of impedance mismatches too, but as you've pointed out, over-sensitivity can be a problem too.

Also thanks about the tip about hi-fi being a slightly different application than your usual shortwave receiver audio amp hiss. Ie, if an inline volume control is needed for hi-fi gear, then audio characteristics may suffer. I guess in that case one needs to look into mid-high impedance phones, DAC amps and so forth. Heh, different forum for that!

Ubbe - again great info, thanks for the tips.
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