Lack of bass in AKG's

[MacDEF]

The TimD forum bot strikes again

 

[Neruda]

Quote:

Originally posted by KurtW I agree with everything kwkarth said except the part about going down to the sub basement. Yes, I can feed them a 20 Hz signal and if I jack up the level enough I can hear it. If I jack it up some more I hear mostly doubling.

Kurt, that's a sure sign that you're not giving them enough power. I heard them through the SAC, and I know what happened to their bass response. They certainly lack the lowest octave without proper amplification; but give 'em a watt or two and baby, will they rumble

 

[Possum]

Maybe because the SAC was designed for the K1000, it might be designed to boost the lowest bass frequencies? If so, that boost would also help the K501's. Try a couple of other headphones with the SAC to see if this is happening.

 

[gloco]

Quote:

Originally posted by Neruda They certainly lack the lowest octave without proper amplification; but give 'em a watt or two and baby, will they rumble

O boy, these things do sound like they put out sweet sound with the proper power behind them. Depending on the JMT built amp i may need to squander a few more funds on a amp. Would the Corda drive the 501's well? Or do they need a serious, expensive amp?

George

 

[kwkarth]

Quote:

Maybe because the SAC was designed for the K1000, it might be designed to boost the lowest bass frequencies? If so, that boost would also help the K501's. Try a couple of other headphones with the SAC to see if this is happening.

Possum,
The SAC does not boost anything. It is flat from 2Hz to 200kHz +-0.5dB. It is a marvelous amp and sounds incredible with every headphone I have including my Ety's, Senn HD-580, Grados, Beyer DT-250... The only exception is my Sony CD-3000's sound a little bright, which I think is the headphones and not the amp.

Quote:

"The bottom line is this: whatever amp your using, if you think the bass is just right on the HD580/600or the V6, you'll think it's a little thin on the K501. If you think the bass is too heavy on the HD580/600 or V6, you might find the K501 to be just right."

Kurt,
That might be true for amps that you've used, but this is not the case for the SAC. It lightens and tightens up the 580's and solidifies and fills in the 501's. Come to our meet on Sunday and hear for yourself. Regarding doubling, feed enough dirty power to any underdamped driver and you can make it double. Are you sure you didn't run your amp into clipping? My 501's play my 21.5Hz test tone clear as a bell on either and both channels.
Happy Listening!

 

[Xander]

Damnit! I wanna go to one of these meet things, too..

 

[KurtW]

I haven't tried the K501 with the SAC, but I have tried them with the Max, MOH, Sugden HeadMaster, microZOTL and Corda, to name a few. All of these amps have plenty of power for the 501, unless you're planning to ruin your hearing or use them as speakers.
Quote:

but give 'em a watt or two and baby, will they rumble

That's exactly what I heard, rumbling at twice the frequency I was feeding it when I jacked up the power. But as I backed off on the power and raised the frequency I had to turn them down because it was way too loud at "normal" frequencies. It wasn't the amp that was doubling, it was the headphones. I didn't try it but I bet the same thing would happen on the HD600s. Most headphones don't do the bottom octave all that well. Neither do most speakers.

I don't doubt the the 501s sound really good with the SAC...is this a good amp for all phones? Anyway they don't make them anymore and hardly anyone has them so for the rest of us, don't expect rumbling bass out of the K501. This is not mean as a criticism.

 

[Neruda]

hey, that'd be cool...I wonder if we could drag any bay area 'fizers to our meet! I'd like to meet MacDEF and bash his senns face-to-face!

just kidding

 

[KurtW]

"It lightens and tightens up the 580's and solidifies and fills in the 501's. Come to our meet on Sunday and hear for yourself."

That's pretty amazing if you're telling me the SAC makes the bass of the 580s and 501 similar in intensity compared to the rest of the frequency range. It would seems that this is the greatest amp ever made...why hasn't everyone gone crazy over them? Maybe I'll fly up to hear that. The frequency doubling only happened at quite high levels. I can put a scope on the amp to verify it's clean, but most any transducer with double if you feed it enough power.

 

[Neruda]

I think the beauty of this amp is in its power. 1.2 watts into 120 ohms is a hell of a lot.

 

[kwkarth]

Quote:

Originally posted by KurtW [size=xx-small]"It lightens and tightens up the 580's and solidifies and fills in the 501's. Come to our meet on Sunday and hear for yourself." That's pretty amazing if you're telling me the SAC makes the bass of the 580s and 501 similar in intensity compared to the rest of the frequency range. It would seems that this is the greatest amp ever made...why hasn't everyone gone crazy over them? Maybe I'll fly up to hear that. The frequency doubling only happened at quite high levels. I can put a scope on the amp to verify it's clean, but most any transducer with double if you feed it enough power. [/size]

Absolutely, I agree. I can get the 501's to double @ 20Hz if I turn it up enough. They sound to me like they're 6-8dB down @ 20Hz from 40Hz.

The SAC does seem to bring all the cans that I have closer together in sound character. I like the Senns better because they brighten and tighten up a bit and the 501 take on more substance, punch and body. The Ety's sound magical with the SAC as well. In the 4P configuration I wasn't too thrilled with them but with 68 ohm resistors in series, they take on that magical, alive, you are there, quality that I love about great headphones. Ona scale of 1-10, with 10 being reality, I would place the 580's at 6.5, the 4P's at 7, the Grados at 7.5, the K-501's at 8.9, the 4S's at 9 and the K-1000/subwoofer combo at 9.5.
Not bad at all.
Happy listening!!

 

[dngl]

So the consensus is that the akg 501s are good with the proper amplification... is the Melos SHA-1 proper amplification? I can't really find detailed specs on it or anything, so has anyone here tried it themselves? Thanks.

 

[Daniel Pumphrey]

The real needs of the AKG K-501 should be defined by the current capability and not the wattage rating of the amp intended to drive it, from what I have been able to determine.
Some designs like the Szekeres and even the dreaded old 386 are high current amps. I think this is why I still somewhat like my old hot-rodded 386 design. It has a 250ma capability which can override the crappy specs of this old opamp to a degree and sound pretty good with inefficient headphones. This is also why I am excited about the new 627-Buf 634 amp. It has a much higher current capability than many designs. This is not needed with the Etymotic ER4-S, but the K-501 loves the added power.
A 10 Watt Class A amp can sound better than a 50-100 watt standard design for standard loudspeaker audio.
Most Headphone amps are rated according to the wattage and not the current capability they have mainly because they are built with low current devices.
Kurt W.; The SAC amp was made only for the AKG K-1000 phones and has a special connector which will not work for other phones without modification. This is why you have not heard about it. This amp was also very expensive as well and is now discontinued. It is basicly a 1 watt Class A design. SAC will be making an even more expensive amp to replace it I hear.
I am sure the SAC amp made for the K-1000 has good current capability also, and this is why it sounds so good with the 501 too. Just look at the Heatsinks, it is obviously a high current amp.
http://www.head-fi.org/forums/showth...&threadid=3969
Dan

 

[kwkarth]

Quote:

Originally posted by Daniel Pumphrey The real needs of the AKG K-501 should be defined by the current capability and not the wattage rating of the amp intended to drive it, from what I have been able to determine. ....Just look at the Heatsinks, it is obviously a high current amp. Dan

I agree, the 501's need to sink current. BTW, speaking of heat sinks, that all the SAC is!

One big heat sink and btw, it runs so warm, I have a 3" fan (pentium cooler) on top of the case running 24x7 to keep the case temp under 100deg.

 

[KurtW]

Maybe the K501 has a huge rise in impedance at the low frequencies that make it hard to drive. A more powerful amp that can generate some good levels of current at very high impedances would then probably sound better, especially at higher listening levels. It will not, however, correct for normal low frequency rolloff.

I made some measurements with a signal generator and a SPL meter. The headphones sit on a small block of foam with the SPL meter mic in the center flush with the foam so there is a small chamber formed with the mic at the center. This doesn't duplicate the ear's chamber but was meant for some relative rather than absolute measurements. I measured the HD580, K501 and Sony V6. The volume was set with pink noise at 80dB, although this also was very close to the 1kHz level. The generator puts out tones in 1/3 octave steps. Relative to the 1kHz level, here are the levels at 200, 100, 50, 30 and 20 Hz:

Sony V6: -0, +1, +1, -3, -8
HD 580: -1.5, -3, -11, -19, -24
AKG K501: -1, -4, -12, -23, -30

I also measured the K501 at a 90dB SPL and got the same result. This tells me that it wasn't limited by the amp not being able to drive them, because I saw no compression as I increased the level. I also listened to the tones with all three phones and what I heard was similar to the measured result.

My standard bass test CD for music has been Lyle Lovett's Road to Ensenada. Particularly during the bridge of this song, starting around 2:20 into the song there is some really deep bass that shakes everything in the room when played on my NHT 3.3 speakers. It's also pretty convincing when placed on the Sony V6. With the HD580 and HD600 however I only get a hint of it, and on the K501 it's totally missing when played at similar (ie, normal for me) volumes.