The Problem With Loudspeakers Page 2

For me, genuine understanding is usually precipitated by small judgment-free moments of extra-ordinary lucidity. Moments where having minimal preconceptions led to a surprising discovery. I mention this because all the above ‘Herb-chatter’ was precipitated by a single audio experiment that I swore I wouldn’t share in public – but now I feel I must.

When I began reviewing headphones for Stereophile, the first things I noticed were how direct, dynamic and transparent they were. Presence, detail and voice-articulation far exceeded anything I had experienced with box speakers. On simple two-microphone, spaced-omni, Blumlein pair, or binaural, recordings: headphones made me feel like I was there – in the room with the musicians. Think immediate, intimate, and present – like my ears were the microphones.

After studying headphones for a year, I began to think that the headphone amps I was using were the weak link: that they were limiting headphone dynamics, vividness, and transparency. I wondered about the issues I alluded to above. I began to ask the designers of the best headphones what amps they used to evaluate their creations. To my surprise, several were using low-powered single-ended directly heated triode amps. To my greater surprise, the amps they said they were using were just regular loudspeaker amplifiers; with no special provisions for protecting delicate headphone diaphragms. Naturally, I was forced to make up a set of balanced-to-banana headphone cables and connect my JPS Labs Abyss AB-1266 Phi headphones directly to the output jacks of my First Watt J2. And WOW!

That was it folks.

That was the moment I first experienced the complete full potential of two-channel audio. Every audio experience before that fell into the category of a messy constricted boom-box thing. This was the moment I realized I needed a whole new vocabulary to describe what I was experiencing. Reproduction was clear and vivid beyond words.

The first words that jumped into my head were: direct, explicit, descriptive, un-impeded, immediate, essence, true, graspable, and some new word that means more transparent than the old word transparent.

I played Todd Garfinkle’s spaced-omni two microphone pure DSD2x recording of Puente Celeste’s Nama (M-A recordings MA030) through a Holo Audio Spring Level 3 Katsune Edition DAC feeding a line-level input of the Pass Labs HPA-1 headphone amp/line-level preamplifier driving the 25W First Watt J2.

With this setup, it was easy to compare the output of the J2 power amplifier to the output of the headphone jack on the HPA-1 headphone amplifier that proceeded the J2 in the audio chain. But surprisingly, there was no comparison; and I have still not recovered from how the output of the basic power amplifier could be so much more intense and real. When I closed my eyes, the performers and their instruments occupied an utterly life-like three-dimensional space with a reach out and touch it crystalline presence. I had never experienced anything like this.

I was so excited I called my headphone buddy Steve Guttenberg and literally screamed into the phone, “I found it! The Holy Grail/the Dead Sea Scrolls/the Secret of the Pyramids… of Two-Channel Audio!” The next day, I brought him my DIY cables and we tried it together. It was so amazing we both laughed.

Over the weeks and months that followed, I connected the Abyss AB-1266 Phi, the Audeze LCD-4, and the HiFiMan Susvara headphones to a variety of basic tube and solid-state power amplifiers including the Line Magnetic LM-518, the Pass Labs XA25, and the PrimaLuna Prologue Premium. The only “headphone amp” that equaled any of these amplifiers was HiFiMan’s own $15,000 USD EF-1000; which outputs 20 watts class-A (with high gain and high voltage) into a 35-ohm headphone load.

The easy, obvious answer as to why these three world-class headphones sounded more real and transparent than any audio reproduction I’ve known is: these basic power amplifier’s connected via a line-level preamp offered more gain and more clean watts than any of the headphone amps I used. But! Don’t forget…

These headphones are all full-range transducers with high ruler-flat impedances and near zero phase rotation. They are pretty much pure resistance. They are also, compared to box speakers, extremely sensitive: the Abyss requires only 320mV to reach 90dB SPL. Most importantly, there were no crossovers, voltage dividers, or filter networks. Nothing was gumming up the combustion chamber or messing with the compression ratio. There was no time-smearing energy-robbing mishegas in some black hole between the amp and the quivering cones.

I am explaining all this because I strongly believe the full-range, crossover-less, benign impedance, high sensitivity, and direct connective-ness, that headphones offer should – and could – be a model for floor-standing audiophile speakers. I believe I have experienced our audio future and it is simple, sensitive, resistive, and direct.

Is there an argument against this?

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grantray's picture

1. Thank god you answered your run of what-ifs with a headphone and not the WE755A.
2. What load were you hooking the phones up when going direct to DH-SET amp? 4, 8, or 16?

Herb Reichert's picture

I have a tendency to prefer the 4-ohm tap - but I always try both

grantray's picture

How about a shot of those cables you made?

PeterInVan's picture

As much as I enjoy my LCD-2F headphones, my personal preference is listening to the KEF LS50W powered speakers.
KEF has eliminated the need for amps, preamps, DACs, interconnects ... all external devices.
They have dedicated DACS and Amplifiers for each speaker, as well as DSP processing for room tuning.
The LS50W is a worthy alternative to high end headphones in terms of power, sound quality, sound stage and imaging.

geoffreyvanhouwaert's picture

straight into the speakerouputs, and here i was about to buy a pass hpa-1

Herb Reichert's picture

the Pass Labs HPA-1 is a very fine headphone amplifier, but is is (to my taste) a little shy on gain for headphones like the Abyss AB-1266 Phi and HiFiMan Susvara which, when connected to the First Watt J2 or SIT3 amplifiers become stunningly clear and untethered dynamically.

I like gain and energy in my hifi chain - it works like caffeine

I am certain both headphone manufacturers would STRONGLY discourage you from trying my experiments and void your warranty if they found out.

just saying :)

Ortofan's picture

... from those integrated amps and receivers whose headphone outputs are connected to the power amp output through a single resistor?
Of course, that would increase the output impedance of the driving circuit and could result in frequency response variations that are a function of the impedance variations of the headphones.

pbarach's picture

I don't have headphones wired for balanced output. So to duplicate what you did, Herb, I need a headphone cable that terminates in banana plugs. My DAC source feeds into a line-level preamp, which is connected to a basic power amp, and then the banana plugs are connected to the speaker outputs of the amp. Is that correct?

Herb Reichert's picture

Just like speakers - but you must be extremely careful to avoid turn-on spikes or signals that could damage the headphone drivers.

Everclear's picture

Can a headphone amp which can put out more watts, say like the Sim Audio headphone amp for example, do the job? .........

Everclear's picture

Another example is Cary Audio CAD-300 SEI integrated amp ........ It is supposed to put out 15 tube watts via the headphone output ...........

Herb Reichert's picture

implies that these headphones don't just need more watts. They need more gain and higher voltage and definitely no series resistance.

ednaz's picture

...of five foot tall left and right headphone cups sitting where my speakers sit. Not pretty.

DH's picture

Use a system like DEQX, which is one box that both time aligns your drivers and does DRC; or buy one of the new speakers like the Kii Three or Dutch&Dutch - both of which do much of the same on their own, and include amps matched to the drivers in the speakers.

None of the above solutions is a million dollars of weighs 250 lbs.

Many of us don't enjoy either the sound of headphones or wearing them. That's the LAST solution I'd go to for enjoyable listening.

Everclear's picture

A planar magnetic loudspeaker like the Magnapans may come close to the type of loudspeaker HR is describing ....... similar to the planar magnetic headphones .........

Everclear's picture

Sorry ......... Correct spelling Magnepan ...........

Everclear's picture

Also, electrostatic headphones and loudspeakers have similar properties .............

Everclear's picture

Electrostatic transducers do not have uniform resistive load, but for headphones and some loudspeakers, they are crossover less designs .............

Herb Reichert's picture

What I am lobbying for are speakers with high ruler-flat impedance, high sensitivity, minimum phase, and minimum excursional non-linearities ----- like good headphones.

To me, speakers with reactive impedances below 2-ohms are broken and non-functional -- no matter how good their frequency responce measures

Duck851's picture

*Edit – (I'm assuming you mean 'Grado' nor 'Grade.' If I'm wrong, I'll change it back!

Didn't Grado whip up a pair of speakers that used their headphone drivers?

Duck851's picture

Yep, Grado, not Grade - thanks! Do you recall them?

canuckmgh's picture

Cube Audio, Nenuphar floorstander, single 10" driver with three whizzers, sensitivity 92dB, impedance 6 Ohms, claimed freq. resp. 30Hz - 18kHz (6dB). Reviewed elsewhere and given its top award.

Alex Halberstadt's picture

genius, Herb!

Everclear's picture

Probably the appropriate title of the article is "Loudspeakers, the PITA (not the bread) devices" :-) ..........

kenyanrandrews's picture

I am a noobie to this game so forgive my ignorance of the measurements and science - much of this article was not understandable for me.....but.... I have just bought a Musical Fidelity A1 amp to take the place of the Onkyo TX8270. Powering small bookshelf speakers. What I hear is less resistance, higher energy and less digital trickery leading to a WAY nicer sound from the simple A1 amp. Is this the gist of your experiment?

rt66indierock's picture

I can think of three off the top of my head frequency range, intermodulation distortion and frequency mixing.

And to shoot the messenger you supported MQA I have to question your judgement.

Genez's picture

That is why I refer to my Audience 1+1 V2's as my 'off head' headphones.
I simply adjust the bottom with some linear dynamic EQ to room acoustics and enjoy. To achieve this effect these speakers need pinpoint, precise adjustments, in height,width,and angle. Then the magic begins.

MixerRog's picture

Having build & designed both Tube Amplifiers & Solid State amplifiers for years. I much prefer Solid State sound with a solid non boomy bass due to the very low output impedance of the Solid State Amp versus the much higher output impedance of a Tube Amp. A low output impedance causes a much higher damping factor as you likely know which in turn causes much less cone overshoot in the bass region. Tube Amplifiers in general have much higher harmonic distortion also.

I have told many people if they want to have a tube sound with lower harmonic distortion also, just put resistance is series with the speaker such as small gauge speaker wire or high power resistors.

Damping Factor is defined as speaker impedance divided by amplifier impedance so as an example, a solid state amp with a .1 ohm output impedance & an 8 ohm speaker would have a damping factor of 80 versus a tube amp with output of 8 ohms & 8 ohm speaker having a damping factor of 1! Tube Amplifier feedback can cause this the damping factor to rise as high as about 20 but that is even rare that I have seen while very good Solid State Amps can even approach a damping Factor of 1000!

For me after over 50 years of Audio work, the single biggest sound difference of Tube versus Solid State sound is due to the Damping Factor difference.