Review: SPL Phonitor

[Dreadhead]

Also posted on H-F:

Review of the SPL Phonitor

Introduction:
Last year I started to read about this new amplifier from SPL with its exotic crossfeed and I had to hear it. SPL America generously agreed to send me a Phonitor sample for review on Head-Fi and in short I am extremely impressed with the amplifier.

On top of that the Phonitor has an amazing fully adjustable crossfeed circuitry that does an amazingly effective job at recreating a speaker setup. That’s the real purpose this amplifier: to replace speakers in the monitoring environment for professional mastering and recording engineers and my understanding is that it has been a hit among that crowd and I understand why!

Amplifier Features:
1 pair of XLR inputs
1 pair of Loop outputs
Single ¼” Headphone Jack
120 V Peak to Peak Output Voltage Swing (HUGE)
Fully adjustable crossfeed
Other monitoring features (see manual on the SPL Website)

Headphones Used: Sennheiser HD650, Denon AH-D5000, Sony MDR-SA5000

Similar Products Used: Headamp GS-X, Balanced Beta22

Sources: Bel Canto DAC3

Music:
O Brother Where Are Thou? Soundtrack, Various
In Rainbows, Radiohead
In Between Dreams, Jack Johnson
A Rush of Blood to The Head, Coldplay
Kid A, Radiohead

Fit an Finish:
The Phonitor is a utilitarian looking amplifier but SPL knows how to make utilitarian look and feel luxurious because everything about this amp is solid and professional. It’s an object made to be used and used well.

Listening Impressions:
This is a very detailed and accurate amp with a wonderful soundstage and draws out the details in any music and source you attach to it. This is how amplifiers should be in my book. Wire with gain!

Comparison with the GS-X:
Without the crossfeed I am unable to really find a good reason to pick between the Phonitor and my GS-X driving my headphones single ended (balanced drive appears to give the GS-X a slight edge). The sounds are very similar thought I would say the SPL is possibly (I am really not sure) a little less crisp up high than the GS-X but that’s about it. In the end it took many many trips back and forth and I’d be very very happy with either amp (well I already own one of them)

Crossfeed (Speaker Simulation) Functionality:
The idea behind the Phonitor is to have the professional engineer sit in their mastering/monitoring studio and tune the crossfeed until the sound field matches that of their room. I did this with my speaker setup and the results after much tweaking are downright impressive. It’s like listening to speaker but still with all the detail and crispness that headphones give you. You have to try it!

Measurements Etc.:
I’ve done two different sets of measurements on the SPL Phonitor. The first set were done using the RightMark Audio Analyzer (RMAA) and my M-audio Transit USB to get measured response at the output. The other test measured the actual response of the headphones using my calibrated Behringer ECM8000 measurement microphone, headphone coupler, Room EQ Wizard Software (REW), and Edirol FA-66 audio interface. In both cases the source was my Bel Canto DAC3 and were done with no crossfeed on the Phonitor.

RMAA Results:
Frequency response (multi-tone): +0.08, -0.14 dB (20 Hz - 20 kHz)
Noise Floor: -87.8 dBA
Dynamic Range: 87.7 dBA
THD: 0.0013%
IMD + Noise: 0.0084
Stereo Crosstalk: -77.7dB

In general these results except for the crosstalk which is nearly 20dB higher than my GS-X. The rest are within the same sort of range exhibited by the GS-X though generally a little larger. The crosstalk is less of a concern with this amp because most users will use it with the crossfeed on and the crosstalk will be much higher then : ).

REW Results:
This led me to wonder what the results would be with actual headphone response and here I compared the Phonitor with the GS-X after careful volume matching. Much to my surprise the measured response of the headphones (HD650 and D5000) with two amps was identical. This was suprising because the heaphone out of the Phonitor is supposed to be 9 ohms which should lead to a bass bump with the HD650s but I could not observe one at all in my REW measurements. I have attached a plot of the HD650 spectrum with two curves though you will see only one (I assure you that there are 2).


Summary:
Great amplifier and great crossfeed! Highly recommended.

I am sorely tempted to buy one of these amplifiers but I already have a headphone amp and have many others on the way so that will have to wait. I am talking to the product designers at SPL and hoping that they release just the crossfeed portion of their technology in a separate package that I can integrate into my system. I will miss this amp when I ship it out on Saturday.

[jinp6301]

So is this like the Smyth thing that they had at canjam last year but for a 2.0 setup and thats used without mics?

[Dreadhead]

So is this like the Smyth thing that they had at canjam last year but for a 2.0 setup and thats used without mics?

No the Smyth box uses measured IRFS to model the effect of crossfeed the Phonitor uses your ears and a series of adjustments to tune your experience. You can for example increase the speaker angle the crossfeed amount etc. More interactive and tunable.

[jinp6301]

Ahh, I see. Thanks for the clarification. Looks real interesting. I hope more of these come out into the wild

[agile_one]

Nice review, Chris. I was looking forward to your impressions, because I am predispoded to like SPL gear. I have the SPL Volume2 balanced volume control, and it is a fantastic piece. Basically a single source balanced preamp. What is the msrp of the Phonitor?

[Dreadhead]

Nice review, Chris. I was looking forward to your impressions, because I am predispoded to like SPL gear. I have the SPL Volume2 balanced volume control, and it is a fantastic piece. Basically a single source balanced preamp. What is the msrp of the Phonitor?

The MSRP is $2149 but the street price is significantly lower than that. You will need to talk to an SPL dealer to get the street price since I don't know it.

[Dusty Chalk]

I'm surprised you didn't mention the trouble it has driving low impedance cans. Aren't the Sony's low impedance? It made the L3000 sound broken.

[Dreadhead]

I'm surprised you didn't mention the trouble it has driving low impedance cans. Aren't the Sony's low impedance? It made the L3000 sound broken.

Dusty I'm really not sure what happened with that and I was going to mention it but then I tried it with the d5000s (32 ohm) and the SA5K at around 70 ohms and I didn't get the same effect. I'm not sure what it was. Maybe those two have flatter impedance curves but I did the RAW measurements on the D5000s and the two amps came out identical much like the HD650s.

That's why I left it out since it's a mystery to me. I don't know.....

[Dusty Chalk]

Agreed. The way I phrased the generality is unfounded.

[grawk]

Not understanding it isn't a reason to leave it out. The L3000s sounded really bad out of the phonitor, and much better out of the GSX singled ended when fed by the same source.

[Dreadhead]

Not understanding it isn't a reason to leave it out. The L3000s sounded really bad out of the phonitor, and much better out of the GSX singled ended when fed by the same source.

Yeah that was my impression but I believe it was only mine. Did someone else try the L3000 between the two? If you two corroborate then I'll at least fix my review over at HF to include that. I had come around to thinking that I was just getting used to the cans since it was the first time I'd put them on. I honestly wasn't at all sure if it had just been a "meet" artifact.

As usual Grawk is keeping me on the straight and narrow

[Dreadhead]

Agreed. The way I phrased the generality is unfounded.

Dusty, did you try them out of the Phonitor? If you match my recollection that would help me be sure I wasn't just being insane.


What I should have done is switched back to the phonitor after the GS-X and seen what happened

[Grahame]

The MSRP is $2149 but the street price is significantly lower than that. You will need to talk to an SPL dealer to get the street price since I don't know it.

Google found $1849.00 from here
Sound Performance Lab (SPL)*-*SPL Phonitor - Pro Audio Sales - AudioLot - 888-224-3343

[grawk]

$1934 on ebay too

[Dusty Chalk]

Dusty, did you try them out of the Phonitor? If you match my recollection that would help me be sure I wasn't just being insane.


What I should have done is switched back to the phonitor after the GS-X and seen what happened

The short answer is no, but "no bass" does not describe the L3000's, that was good enough for me at the time. Colin?

Do you still have it? I'm pretty sure your two weeks are up, but if not and if you want, I could bring them by again, Friday evening or something briefly. (Alexandria is pretty convenient to me from work.)

As well as any other phones that we could test any theories with. The MDR-F1 has a pretty "testing" impedance.

Anyway, I'm going to assume not, but if so, speak up quickly, I'll make sure I have them with me tomorrow.

[cetoole]

I only listened to the L3k SE out of Dan's (former) M³, since the Phonitor was hooked to Chris's computer for the source. I certainly wouldnt say they were shy on the bass in any respect. I didnt actually try the phonitor for anything.

[Dreadhead]

The short answer is no, but "no bass" does not describe the L3000's, that was good enough for me at the time. Colin?

Do you still have it? I'm pretty sure your two weeks are up, but if not and if you want, I could bring them by again, Friday evening or something briefly. (Alexandria is pretty convenient to me from work.)

As well as any other phones that we could test any theories with. The MDR-F1 has a pretty "testing" impedance.

Anyway, I'm going to assume not, but if so, speak up quickly, I'll make sure I have them with me tomorrow.

Dusty, I was running late but I did ship it out today. My two weeks were up 2 days ago. Massive fires at work. My initial impression was not a lack of bass it was that the baritone was obscured but I think that was my head getting used to the headphones not anything else. I have done fairly extensive A/B with the 32 ohm D5000 and I could find nothing so my guess is that it was my own brain. The scientist in me fell down on that one, I should have gone back but I was enjoying the chatting and I got distracted.

To be clear I thought the L3k had great bass out of both of the amps. I just thought it wasn't as controlled out of the Phonitor but I believe now that this was my mistake for not rechecking and it was just a mis-impression. That's why I originally did not include it. I'm not big on "inklings" etc.

[Smeggy]

Nice, and I hope you get some success with a standalone crossfeed box. That would be outstanding. I like the effect of crossfeed in general but I've yet to hear one that wasn't highly detrimental to the overall sonics.

[Dreadhead]

**** update *****
One of the people from SPL contacted me and pointed out that my Dyanmic range number made little sense and I realized he was right. The dynamic range as measured from RMAA is going to come out about the noise floor because of how the test is set up and that does not necssarily represent the real dynamic range. SPL claims a dynamic range of 129 dBA and noise floor of -97dBu using their Audio Precision analyzer (drool)

[Voltron]

Nice job on the review, Chris. I forgot how much I dislike doing them when I did the TTVJ FET-A review the other night.

Anyway, as I mentioned on HF, I think a Phonitor / DA11 comparison might be very interesting. If I am understanding, then they do some similar things, but in very different ways. I have no idea if anybody attending CanJam has a Phonitor, but maybe you could capitalize on your contact with SPL and request that a unit be made available for CanJam. It could be shipped to JP or somebody involved in running the thing, or you could just get another unit in May and bring it with you!

Cheers.