The Beyerdynamic DT48 Arrives... - Page 234

Good points you made, here. I'm learning a lot from this thread.  Up until the big valley in the highs that shows up on Tyll's graph, they sound very flat to my ears....and even more important....realistic....true to the way acoustic instruments sound in real life. However what I do notice when comparing them to the 240DF and the hd580, is that there's a lot more energy in that lower treble area with those other phones. With high pitched horns and strings I'm hearing significantly more brightness with the DF and 580 compared to the dt48. So perhaps it's simply be the difference between free field equalization and DF equalization that accounts for that. I think the 580 is DF equalized, as well as the 'DF', obviously.  The dt48 corresponds closer to how I hear horns in real life, having played in large jazz bands and orchestras throughout my early years, and also attending a lot of live performances. So, as you say, the valley in the lower treble on Tyll's graph may very well be intentional. Perhaps I simply prefer the sound of free field equalization over DF equalization. The dt48 sounds even more 'real'...true to life... than those other two phones, which are quite good in their own rights. It's definitely a very unique listening experience compared to anything else I've heard. If I could only keep one phone for the rest of my life it would be a very tough choice between the 580 and the dt48.. 

Quote:

Originally Posted by shamu144 

This is consistant with my impressions as well... The 2.5khz peak can be a bit nasty (ringing ?), depending on your HRTF. I read that the 12/13khz frequency range is used by the ear for spatial location in a FF soundfield which would explain the peak as well.

 

What you have to understand is that those peaks and valleys ideally DO follow an intention... Do NOT try to eradicate them by equalizing (or very slightly to fine tune to your own HRTF). They are not necesarly a bad thing. In fact, what I see is that the DT48 FR follows pretty closely the theorical Free Field frequency response... For some it will work better than others, because the FF frequency response is much more sensitive to HRTF variations than the DF for example.

 

 

 

Very good explanation...thanks! That explains, at least in part, why there's such disagreement on the forum as to which phone sounds 'flattest'. Glad I'm not a headphone manufacturer! I can imagine the headaches they go through trying to engineer a 'flat'/natural sounding phone. I'm going to have another listen with sinegen later. I'm curious why I'm not getting any peak around 9 or 10k. My testing last night was very brief, so I want to do it again. However, the 10k peak with the k702 was very obvious.

Quote:

Originally Posted by vid 

I don't mean to doubt your hearing, lejaz. And in any case, I've never heard the DT 48 (nor the DF), so I'm going purely on speculation here.

 

From what I understand, your ear canal naturally resonates at around 3 and 10 kHz (and 15 kHz?). Which frequencies they are exactly depends on the length of your ear canal, and whether or not you hear peaks there depends on your phones.

 

I'm not an expert on this, but because the ear canal naturally emphasizes the sound around those frequencies, I would assume that your brain has come to automatically account for it. I.e. the brain expects to hear a certain amount of emphasis on those frequencies, and thus it sounds normal to you instead of peaky. If the source emphasizes those frequencies either up or down, you'd hear that as a deviation, i.e. a peak or a dip.

 

From what I understand, if you were a headphone manufacturer and wanted your phones to conform to f.e. the free field spec, you'd get yourself a dummy head to test on and tweak the phones until the dummy head gave you a graph that matched the free field curve. If you then subtracted the free field graph from the graph of your phones, you'd get a flat line, i.e. your phones would produce sound that got bounced around a certain way, arriving at the eardrum of that dummy in a certain way and its dummy brain would interpret it as flat. (I'm not going to hazard a guess as to whether the free field curve represents anything accurately or not, because I don't know.)

 

Again, I'm not an expert, but I assume the problem comes in when you (being the headphone manufacturer) take your phones out of the lab and plant them on the heads of random people. Their ears vary from each other (and their brains do as well), meaning that a different type of sound would arrive at their eardrums than what you predicted in the lab, and their brain would process it in a different way. Thus your phones wouldn't sound flat anymore. The free field curve, for instance, seems to center around 3 kHz or so, but if your test subject had a shorter or longer ear canal, their 3 kHz ear canal resonance wouldn't be exactly at 3 kHz but a bit below or above that, resulting in peaks and dips at that area when they listen to your phones.

 

Anyway, that's how I understand it, and I don't understand it too well. (If lejaz hears a peak at 2400 Hz and EYEdROP has it at 2700 Hz, and assuming those are the 3 kHz ear canal resonances showing up, then lejaz possibly has a longer ear canal, which would be roughly 3.5 cm or so vs. 3.1 for EYEdROP. But that's just a guess.)

If your ear canal is about 3.5 cm (there's no guarantee that it actually is), then the second point of resonance would be at about 7.2 kHz and the third one somewhere around 12 kHz. But that depends on whether the peak you hear at 2400 Hz is due to an ear canal resonance or something else.

Also, I wonder how much ear wax would affect all this. I would imagine that the wax creates constrictions within the ear canal, thus changing the resonances. (Not saying anyone has waxy ears, just pondering.)

I did a more thorough test tonight and there is a bit of a peak at around 10,400hz on my dt48 (I didn't have my level on the amp high enough last night to hear it, being a bit overly careful about not damaging my hearing with loud, high tones) and there's peaks also around 2350, 3100, and the 4800-5000 region. After about 5500 they roll off a lot and I can barely hear anything after about 6200 up to the little 10,400 peak. I'm also able to hear 50hz tonight since I have the volume up higher on my amp. I read recently that the highest note on a piano is under 4000hz, so really, most of our listening is in the mids and the bass region, and the dt48 is very flat there... other than the peak in the 2400 region from the ear canal resonance. If I do any more testing, I'll probably test the 240DF next. 

Quote:

Originally Posted by lejaz 

Mine seems to have a big valley around 6k as in the graph. It was very hard to hear anything above 7k on mine, but that corresponds to the equal loudness curve as I understand it. The k702 goes up at 10k whereas the dt48 is pretty much inaudible there. The 702 also is easily heard below 50hz, but not so with the dt48, so my set corresponds to what some have said about their poor extension on both ends. The dt48 are never sibilant which is likely due to a significant dip in the low treble area....6-7k. Just noticed a peak at 5k with the 702. No wonder they sound so much brighter than the dt48....big difference at 5k and especially at 10k

 

I can hear 25hz and up to 16khz on the DT48S, so far only tried the S, will test the rest and get back.

Quote:

Originally Posted by maniacal71 

I can hear 25hz and up to 16khz on the DT48S, so far only tried the S, will test the rest and get back.

Did you hear any noticeable valleys or peaks in the midrange, as are shown on the innerfidelity graph? BTW, I wonder about the review Tyll gave them. When he commented that they were fairly colored, was he going by what showed on the graph(which is questionable, imo), or was he going by what he heard with his ears? I suspect it was more the graph that influenced that comment. I can't see how his ears could have found them 'colored'. And to claim that they're colored only based upon that graph is very misleading, imo. I can understand someone not liking them for other reasons, but never heard anyone describe them as 'colored' before. They're far less colored than other popular headphones, imo....possibly one of the most 'uncolored'.

Quote:

Originally Posted by lejaz 

Did you hear any noticeable valleys or peaks in the midrange, as are shown on the innerfidelity graph? BTW, I wonder about the review Tyll gave them. When he commented that they were fairly colored, was he going by what showed on the graph(which is questionable, imo), or was he going by what he heard with his ears? I suspect it was more the graph that influenced that comment. I can't see how his ears could have found them 'colored'. And to claim that they're colored only based upon that graph is very misleading, imo. I can understand someone not liking them for other reasons, but never heard anyone describe them as 'colored' before. They're far less colored than other popular headphones, imo....possibly one of the most 'uncolored'.

 

It is considerably colored only to those who don't put them on for a considerable time. Probably he doesn't know what he is talking about if he did say that.

Even Beyer's own graph has them quite colored in the upper mids and treble, though. -14 dB or so between 1 and 7 kHz, looking at this graph.

I've seen the Sennheiser HD-25 used quite a bit for phonetics studies, where correct presentation of human speech is essential. F.e. in this Google search you can see some of those. Looking at the HD-25 frequency response, they look quite similar in the mids to the DT 48, including the big dip past 2 kHz. Maybe the dip just works well for human voices, who knows. (You can also find a few studies done with the DT 48 if you replace the senns with them in that Google search.)

vid: I think that dip follows the free field equalization curve, if I'm not mistaken. Phones that have DF equalization don't have such a big dip there....and you can easily hear that with your ears. I have both the 240DF and the dt48 and the DF is noticeable brighter due to more upper mids/lower treble....same can be said for the hd580 which has a small rise around 3k. The 240DF also has a bigger spike in the treble at 10,500 than the dt48. Since the dt48A was designed for audiometric testing it makes you wonder about that dip. Perhaps someone will know more about this issue. With some singers I definitely DO notice the extra upper mids/low treble that the DF adds compared to the Beyer. However I'd have to hear the singer live, in person, to know which phone has a more true to life frequency response. As I wrote previously, that dip is also noticeable with high pitched horns and strings, when you do a head to head listen with the hd580. I'm curious if anyone finds them too rolled off there just going by what their ears tell them, not by the graphs.

I don't think it does follow the free field curve, but I may be mistaken just as well. And I am about many things.

The way I understand the free field curve (and diffuse field, and all the others) to be is that the curve is what you'd want the raw frequency response of the headphones to look like. When you calibrate the raw response with the HRTF curve (free field, diffuse field, etc.), you're comparing at each frequency the dB in the raw graph and the dB in the HRTF graph, and you subtract the dB in the HRTF graph from the raw graph. Thus a pair of phones whose raw response looked like the free field curve would get a flat line when compensated for that curve – they wouldn't actually look like the curve itself anymore. For instance, if your HRTF graph had a dB value of 5 at 2000 Hz, you'd subtract 5 dB from the raw response graph – and if your HRTF graph had a dB value of -5, you'd add 5 dB to the raw response graph

So, if the free field curve has a sharp negative dip, it would actually mean that you'd adjust the frequency response graph upwards, not that you'd have a dip in the actual adjusted response graph (or that you'd hear the dip with your ears).

But again, I'm probably mistaken.

I picked up a DT48S 25 ohm yesterday. They were made sometime in the 1970s and recabled with a long Sennheiser cable.  

*A special thanks to headfi user littlebear for gifting me these for the price of shipping and new pads. This is the same person that sold me my DT48E. Truly a nice guy. 

Quick initial impressions: These are a small but crucial step above the modern DT48E 25 ohm. They are ridiculously fast throughout the frequency range, the attack and decay is unreal, even faster than the modern ones. The detail betters the DT48E by a decent amount. The mids seem to have a veil lifted from them and the tonality is simply perfect. The bass is just slightly less in impact, but has very accurate tonality and meshes better with the mids and lets them really shine. The highs sound less harsh and more detailed with very accurate sounding cymbals, but possibly less extended. The soundstage and depth sounds a bit smaller but the imaging is just as good if not better. They really need to remake this model because this is what the DT48 should really sound like. The modern E is close, but a bit thick sounding and slightly less detailed and not as quick in comparison. Still both are an amazing headphone and the sound fundamentally is the same. I am really impressed by these, especially since they are so old. 

Will make a full review once I really get to know them. 

I like your signature EYEdROP.  I've been doing just that(enjoying the music) with my dt48E and now you have to come along and point out it's deficiencies, lol..  

How about comparing them to the 50's version?

Quote:

Originally Posted by EYEdROP 

I picked up a DT48S 25 ohm yesterday. They were made sometime in the 1970s and recabled with a long Sennheiser cable.  

 

*A special thanks to headfi user littlebear for gifting me these for the price of shipping and new pads. This is the same person that sold me my DT48E. Truly a nice guy. 

 

Quick initial impressions: These are a small but crucial step above the modern DT48E 25 ohm. They are ridiculously fast throughout the frequency range, the attack and decay is unreal, even faster than the modern ones. The detail betters the DT48E by a decent amount. The mids seem to have a veil lifted from them and the tonality is simply perfect. The bass is just slightly less in impact, but has very accurate tonality and meshes better with the mids and lets them really shine. The highs sound less harsh and more detailed with very accurate sounding cymbals, but possibly less extended. The soundstage and depth sounds a bit smaller but the imaging is just as good if not better. They really need to remake this model because this is what the DT48 should really sound like. The modern E is close, but a bit thick sounding and slightly less detailed and not as quick in comparison. Still both are an amazing headphone and the sound fundamentally is the same. I am really impressed by these, especially since they are so old. 

 

Will make a full review once I really get to know them. 

Man the 120 ohm adaptor really made a difference with the DT48S model. I have a 1/4" Sennheiser cable > 1/8" Radioshack adaptor > 1/4" Apuresound 120 OHm adaptor. Kind of ridiculous but I love what Im hearing right now. 

I think either my cable needs replaced or the R channel driver is going out because the left is just a little louder than the right. Even with this issue I think these are a bit better than the modern DT48E. I use the balance control to even out the volume, but there is a definite slight difference in tonality between the two drivers. The L channel has more warmth. I have no idea how to use a solder. KBI said APS cable repaired his broken driver, but Im not looking for a $150 snake oil cable. Whats the cheapest way to get them repaired?

Next thing is to try a little Parametric EQ.... 

Quote:

Originally Posted by judy1992 

How about comparing them to the 50's version?

 

No idea, never heard them. I have heard great things about the Nagra DT48S.