Ortofon 2M Black - frequency response charts

I couldn't agree more. To be fair, some people want a flat line because they're doing needledrops for the archive and hope to record for posterity exactly what's on the vinyl. But for day to day playback and sheer enjoyment of the music, I would strongly recommend just finding a cartridge with a sound that hits your own personal sweet spot - after all, your speakers aren't going to give you a flat line and neither are your room acoustics so you might as well just find something that works!

And it's true, excessive loading can have very weird and unpleasant effects on the overall sound. I can vouch for that even from my limited experience so far.

 

As you probably guessed, the answer is that the software adjusts for it. The charts would look a bit weird otherwise. I routinely do a sine sweep test as well as a pink noise test to confirm the results.

Thanks very much for posting your charts - the more, the better. I haven't had time to study them yet but will try tomorrow.

KT88, are those Dynavector charts your own or do they come from the manufacturer? I'm very suspicious of manufacturers' charts - no matter what the cartridge, they always seem to show a flat response.

 

That's true as far as taste goes, in that there is no wrong choice, as you are the one who is listening to your own system. The entire chain as well as the room does effect the sound, so the point at which we should be hearing a good tonal balance and good resolution should be the actual system sound as heard from the loudspeakers at the primary listening position(s). That said, I find that having an accurate "source first" signal design for a system makes it much easier to correct imbalances further down the chain without losing too much resolution. In short, a neutral sounding cartridge with a flat response is an excellent starting point. It is easy to warm or cool things later with amps and loudspeakers which will invariably need some matching to find the best fit.
-Bill

 

There's also the notion that some of us want to get the best we can out of our equipment. Part of this hobby is the quest to attain that and the euphoria if getting better sound when it happens.

 

They are from the manufacturer. You'll have to take-up your objections with Bruel and Kjaer as far as the response of their equipment. The mfr test based upon the standard loading they recommend on these excellent, lab grade devices to confirm performance meets design spec. It's standard mfg QC and the results do show very good performance. I personally have much less faith in charts from the often shareware PC software and questionable test set-up of the novices.
-Bill

 

Hahaha! I agree, you're right to be suspicious of charts from the "the often shareware PC software and questionable test set-up of the novices." It's just that cartridge manufacturers clearly have a strong interest in supplying charts that flatter their products whereas bungling amateurs are at least disinterested. And of course, we have no idea what lab tests Bruel and Kjaer employed, or to what extent those tests replicated real-world conditions. In the days when hi-fi magazines did cartridge tests, I believe their tests produced results that were commonly very different from those advertised by the manufacturer.

But I know nothing about that Dynavector cartridge. If someone wants to send me one, I'll be happy to test it!

Just for the record, although I'm very much an amateur, the Dr Feickert Adjust + Pro software I'm using (complete with Adjust + Pro test record) isn't shareware - it's very expensive and it's a complete package developed especially for bungling amateurs in order to minimise the potential for errors. The tests I've done are checked and double-checked - I do pink noise and sine sweep tests and check one against the other, and I've also calibrated the setup very carefully using the calibration equipment and tests described at the end of the AT150MLX frequency response thread. I'm wide open to comments on my setup, which I've described in detail in this thread and two others.

Having said all that I've just realised that I have made an error - I underestimated the capacitance of my interconnects. Up till now I've been putting the figure at very roughly 100pF but I discovered late yesterday that the capacitance of the supplied interconnect for the SME V is 140pF plus another 15pF for the arm wiring, making a total of 155pF. So all my figures for capacitance understate the true figure by 55pF. I did find that the 2M Black wasn't very sensitive to changes in capacitance so I don't think this makes much difference but it needs to be said.

 

Well, first of all thank you very much indeed for going to the trouble of posting these charts. I'm always interested in hearing what you've got to say about such things. I've got to confess, though, that I don't understand a lot of your post and it leaves me with a lot of questions. I'll just try to stick to a few:

1. So what's your total loading in these tests? You say 300pF in the plugs but how much in the cables and arm wiring? And what impedence are you using - the standard 47K? I'm trying to work out what chart of mine we should be comparing your charts with, if any.

2. I'm not at all comfortable with the idea of using the pink noise tracks on the Ultimate Analogue Test LP for frequency response testing. There's no normal pink noise track. They have a pink noise "lateral" track and a pink noise "vertical" track and state that these are intended to be used for "cartridge demagnetising" or to "loosen up" a new cartridge's suspension. There's no suggestion that these tracks are suitable for use in frequency response testing or for any other tests. Even if they were sufficiently accurate, I'm not sure that splitting a pink noise signal between a lateral-only track and a vertical-only track will produce the same resonances at the same frequencies as a normal, full-range pink noise track. I wish you could do your tests on a normal pink noise track - do you not have one somewhere?

3. You rightly point out that pink noise has a 3dB/octave drop but in your first chart, the pink line is dead straight to 1000Hz, then starts to droop but at nothing like 3dB/octave. I don't understand.

4. The second and third charts - sorry but you completely lost me! I hardly understand a word of any of this. But I'm glad you posted it because it will be greatly to the benefit of people more knowledgeable than me.

So the 2M Black is your cartridge of choice at the moment? I'm glad to hear you have it singing. It's a very fine cartridge (with looks to match) and I like it a lot more this time around than when I first tried it. The only tiny reservation I have about it is that I'm not quite as confident in its tracking as I am with, say, the AT150MLX, but I'm sure if properly set up there would be very few tracks indeed that would defeat it.

 

Very interesting thread. I'm running a 2M Black in a SME M2-10 on a Garrard 301 and with the help of Rob above have already got the overall capacitance in range (about 250pf), which made a huge difference. It looks like there is a real benefit to swapping the 47k load for 33k, so I'll do that too.

 

I have nothing to measure my turntable and interconnect capacitance but based on where the resonance peak has shown up over the years I've been experimenting with loading and capacitance, I estimate it to be around 100-120pF. So with the additional 300pF from my capacitance plugs, I've got a total of about 400-420pF. As for impedence, my phono stage is 47k, but I've added loading plugs that bring the impedence load my cartridge "sees" as about 26k.

I have three test LPs with pink noise and they're all the same. I'm quite glad the AP test LP has lateral and vertical tracks as it gives one the chance to test those aspects of playback. As I explained above, it allowed me to find a roll off in my vertical response that I was able to reduce by adjusting my alignment and VTA.

That's because I used the EQ from izoTope's Ozone mastering plugin suite for that particular set of graphics. The pink noise line there is not intended for measuring pink noise per se but to serve as a guideline for EQing highs. Ozone also provide a 6dB/octave slope guideline. I could have chosen another program such as Adobe Audition, in which I've done comparisons with generated pink noise.

If you go back and read what I wrote, it's fairly clear. But you need to understand how Mid/Side audio corresponds to lateral and vertical signals from phono playback.

 

Ah, good - that explains why you're not seeing the hump at 10kHz. I would have been a bit puzzled otherwise.

Yes I do - but I don't! I will have to do more homework.

 

I tried switching from 47K to 33K on Donald Fagen's Sunken Condos and it did seem to take the edge off it - though whether for the better or worse is probably down to personal taste. The thing to do I suppose would be to get a CD and LP with the same mastering of the same album and do a side-by-side on each setting.

 

Actually I did a bit more testing last night. I hadn't thought of trying the 26k loading with only my interconnect/tt capacitance since changing to a 2M cartridge. I did so and checked the same pink noise graphs. I observed a 3dB "valley" around 10k. When I put the 300pF capacitance plugs back in place and retested, my response was flat again. So in my case, the 10k hump is helping flatten my response.

 

I think there's some consistency there - without the capacitance plugs, your settings would be in the same ballpark as my post #6 which does show a significant drop at 10k. I think putting the 300pF plugs back in would probably push that dip off the chart to the right, leaving the audible range nice and flat. I'll try testing a high capacitance setting before taking this cartridge off again, to see what happens.

 

No, actually it pushes the peak back down to 10k. With only the capacitance of my interconnects/tt, and the 2M Black inductance at 630mH, according to both the Hagerman loading page and the calculator at vinylengine.com, the resonance peak is around 18-20k (assuming my interconnects/tt are between 100-120pF). The loading is pushing the resonance peak at 18-20k down to a level equal to the midrange, but there's a dip between them and the high peak. I noticed this before when I put a couple of potentiometers in a plastic box with leads and used them as variable loading for experimenting. If I went too high on the loading it sucked out the mids. However, putting the 300pf on top of the 100-120pF brings my resonance peak down to 9.8-10k where is counteracts the dip and results in a flat response. The only thing I find weird is that the two loading sites give a calculated optimum loading for 630mH and 400pF at around 38kHz. However, I have loading plugs that give that resulting loading and while they help, I was still getting a rise in the treble.

 

Well, again, I'm struggling a bit to follow everything you're saying but I did promise some more charts and here they are - nice, simple charts drawn from real world conditions!

First, just as a reference, here’s the chart that opened the thread. This is with the “standard” setting on the phono stage – 220pF and 47Kohms. (But please note, there’s a further 155pF of capacitance in my interconnects and arm wiring.)







So, we've got a little hump at 10K, nothing to panic about, but quite a steep fall-off afterwards, which is perhaps a bit more worrying.







Now, I’m raising the capacitance to 330pf (plus 155pF). Impedence is unchanged at 47K:



The hump moves to the left and the fall-off becomes even worse.

And now, with capacitance at the maximum setting on my phono stage, 470pF (plus 155pF). Same impedence:




Hump is even bigger and fall-off verges on the catastrophic.

 

Now, here’s the 330pF setting (plus 155pF) with 33K of impedence:



Well, that’s got rid of the hump but that worrying drop-off is till there.

And finally, here’s 330pF (plus 155pF) with 22K:



It’s nice and flat through much of the range but that fall-off in the upper frequencies looks pretty bad.

 

My conclusions from all of this are:

1. On a standard setting of 220pF (plus wiring) and 47K Ohms, the Ortofon 2M Black has a slight hump at 10K followed by a notable fall-off in frequency response at the top end. All the cartridges I’ve tested so far have had a bit of a hump at or above the 10K mark so that’s not a criticism of the 2M, but I'd be a bit concerned about the upper-end fall-off.

2. If desired, the hump can be eliminated by reducing the impedence to 33K.

3. The fall-off at the top end gets worse as you increase capacitance and gets smaller as you reduce capacitance.


Therefore, if you were searching for a flat response, you would ideally have the impedence at 33K and have the capacitance on your phono stage as low as possible, bearing in mind that there’s always going to be well over 100pF of capacitance in your arm wiring and interconnects anyway. See the charts in post #5.

That’s just my take based on these charts. Stefan, I don't know how far that fits with your calculations - not very well, I suspect! Never mind, people's experiences will vary and it's all down to personal preference in the end.

 

Actually that looks about right for pink noise, which we've already agreed is supposed to fall at 3db/octave. So it may look pretty bad if you're expecting a straight line from left to right, but that's an incorrect representation of pink noise.

 

Unfortunately, as I said in post #27 above, the software adjusts for the 3dB/octave fall so we ARE expecting a straight line from left to right and that chart IS as bad as it looks!

Although we may not agree on capacitance, at least we seem to be agreed on impedence - you say you're on 26k which I don't have a setting for but I found 33k worked well and that's in the same ball park. Either would get rid of the hump.

 

My guesstimate was around 150, based on the treble peaks shown in the (linear) charts.

For the Black, that only puts the 20 and 100 pF settings on the EAR in the recommended range, 220 pF and more (with the early roll-off) would be out of spec. I don't believe Ortofon would care to guess on the user's tonearm and interconnect capacitance when stating their numbers (just like Audio Technica).

Thanks again for the tests.

 

back2vinyl, good practical work.
Your real world testing accords well with the theory, as do your assumptions and conclusions.

I think fixed phono stages generally have too much capacitance. Many carts perform better with just the capacitance of the arm wiring loom.
I'd like to see all decent stages offer at least a high/low position - say 50/200pf since loading is so critical to the sound of MM cartridges.
More expensive stages should offer a decent range of both capacitance and impedance settings.

 

Now you mention it, that's absolutely true IF the figure given by the manufacturers is for total capacitance, including wiring. I'm still mystified by that.

I wish now I'd done a test for 20pF with standard impedence of 47k. But I've still got the cartridge on the arm so I'll do that experiment in the next day or two.[/quote]

 

OK, I did the final, final test on the Ortofon 2M Black and here's the result. The impedence is the standard 47K but capacitance is set as low as it will go on my phono stage, which is 20pF. In addition there's 155pF in my arm wiring/interconnects so the cartridge is actually seeing a total of 175pF. That's within the range of 150pF to 300pF that Ortofon recommends.



I think that's a very nice looking chart indeed and just so's we can savour it even further, here it is again in linear scale:



So what we have is something ruler flat up to 1kHz, then with a tiny roll-off through the most sensitive frequencies of the vocal range and a nice little lift at the top end to give a sheen to the cymbals and sense of air and space. The roll-off at the extreme top end is now very shallow and doesn't even begin until it's beyond most people's hearing range.

If you didn't want the high-end rise, we've already seen that a drop in resistance to 33K gets rid of it. But personally I think that curve is very attractive as it stands.

I'm learning all the time with this but it does seem to me that in general, MM cartridges do have a hump in the range of 10kHz-20kHz. As I think KT88 pointed out in another thread, the last thing you want to do is move this hump to the left (especially if it's already fairly low in the range) because you'll be creating a painful boost in the most sensitive part of the hearing range. However, it does seem that you can get very pleasing results by moving it to the right. Raising capacitance moves it to the left and lowering capacitance moves it to the right. So I think RobHolt is correct and too-high capacitance is the danger in many cases (such as this one), especially since we already have a lot of capacitance in our arm wiring and interconnects.

To sum up again, this cartridge seems to deliver the prettiest looking charts with total capacitance (including wiring) towards the low end of the maker's specified range and in many cases, that will mean a setting of virtually zero on the phono stage itself. Resistance of 47K will give you a beautiful curve like the one immediately above but if ruler-flat is your thing, 33K should do it. All the usual cautions apply - charts can be wrong, the actual sound will vary from system to system, everyone has their own preferences and so on.

 

Talking with the designer of my phono stage, he has always made the point that he needs some capacitance built in to keep his circuit stable. This may not apply to all phono stages, however, because some have a zero setting. Also, a tone arm wire, like the Incognito only adds 50pF to the chain, and that is a fairly long run.

 

Again interesting results, but I can't help but think there's something wrong with your setup. Neither my results nor any of the one's I've seen around the internet for lab tests on the 2M Black show the kind of fall off in the upper treble that you're showing. The lab tests I've seen in various reviews for the 2M Black show a 2dB rise around 18k then a fall off above 20k. You're getting a rise around 11k.