KCTESS5. Your red statement is a valuable suggestion worthy of follow up.
I'd be tempted to get a pair of over the ear hearing protection sort of headphone type things and mount a 3" tang band driver in it making sure to get a good seal.
The enhanced bass is due to using a transconductance amplifier to drive them rather than a voltage source amplifier". Most probably you've read the pertinent articles by Mr. Pass at www.firstwatt.com.
Best regards
I'd be tempted to get a pair of over the ear hearing protection sort of headphone type things and mount a 3" tang band driver in it making sure to get a good seal.
The enhanced bass is due to using a transconductance amplifier to drive them rather than a voltage source amplifier". Most probably you've read the pertinent articles by Mr. Pass at www.firstwatt.com.
Best regards
Antoinel,
Those headphones are absolutely something else. Probably the only headphones I have ever seen for which you might reasonably include room gain in the assessment of bass response, and possibly baffle correction circuitry!
Sorry - I had to say something - they are crackers! Well done.
I am pretty sure you could get away with smaller drivers with the right enclosures and proximity to your ears. It does all get very complex mechanically though. I find the idea intriguing but have never really liked lugging cans on my head.
Those headphones are absolutely something else. Probably the only headphones I have ever seen for which you might reasonably include room gain in the assessment of bass response, and possibly baffle correction circuitry!
Sorry - I had to say something - they are crackers! Well done.
I am pretty sure you could get away with smaller drivers with the right enclosures and proximity to your ears. It does all get very complex mechanically though. I find the idea intriguing but have never really liked lugging cans on my head.
GOOGLYONE: Thank you for your insights, comments and encouragement. These headphones are heavyweights, and do excercise my neck. Please note that this project is simple, highly flexible, with the least pain of assembly; but is coupled with maximum reward. I remember a song from the early nineteen seventees by the Charly Rich [RIP aka the Silver Fox] which said "no one knows what goes on behind closed doors". In my case, I am using the helmet headphones to listen to music for hours instead of renowned STAX electrostatics, and GRADO. Why?; they are damn great sounding. How many other contraptions are in the hands of diyaudiophiles which will never see the light of this forum? Personally, these headphones are the tip of a diyaudio iceberg!
Best regards
Best regards
I think I just found my new avatar for headfi, do you mind Antionel? I can blur your face to protect the innocent if you like?
they look like theyde sound awesome, but I cant imagine the experience being particularly transparent. part of getting the best performance with headphones and their sound stage is getting them to disappear, thats unlikely to ever happen with them, yopu would have to sit immobilized wouldnt you? you should build a powerful portable amp and wear them down the shops one day to get some milk
they look like theyde sound awesome, but I cant imagine the experience being particularly transparent. part of getting the best performance with headphones and their sound stage is getting them to disappear, thats unlikely to ever happen with them, yopu would have to sit immobilized wouldnt you? you should build a powerful portable amp and wear them down the shops one day to get some milk
QUSP: Ha ha ha ha.. Use as you please; no licence required. You wrote:
yopu would have to sit immobilized [got some headroom]wouldnt you? you should build a powerful portable amp [a la Pass] and wear them [with a portable lead-acid battery pack] down the shops one day to get some milk
Doc; you are prescribing hard labour which is the essence of longevity!
yopu would have to sit immobilized [got some headroom]wouldnt you? you should build a powerful portable amp [a la Pass] and wear them [with a portable lead-acid battery pack] down the shops one day to get some milk
Doc; you are prescribing hard labour which is the essence of longevity!
Here's a place to start for drivers or headphone mods:
DIY HiFi Orthodynamic Portable Headphones (aka Ribbon Driver Headphones)
I'm sure with some woodworking skill you could make nice ear pieces. For the headband, ear pads, and putting it all together, you're on your own, a good pair of old school donor headphones might be a good starting point.
DIY HiFi Orthodynamic Portable Headphones (aka Ribbon Driver Headphones)
I'm sure with some woodworking skill you could make nice ear pieces. For the headband, ear pads, and putting it all together, you're on your own, a good pair of old school donor headphones might be a good starting point.
A transconductance or current source amp [TCA] is ideal to drive a piezo tweeter which is a capacitor. The schematic of a TCA generally shows the power output stage connected as "opposed drains" ; for example for MOSFET and SIT device types. A low amplifier damping factor is a consequence of this configuration. A TCA can drive a dead short without damage; unlike its counterpart voltage source amp [VCA] . I build TCA amps using bjt devices, I assess their performance via listenning, and use them to listen to music. The helmet headphones above were successfully used towards this endeavor. A more versatile setup is attached below. Fortunately it is not "Exotic"; but sounds damn good when driven by a TCA. And, one does not need to drive a single screw or nail! Setting it up [and putting it away] is in minutes. A 12 inch subwoofer is made to stand erect at ~90 degrees using a spent Nescafe container [in my case] for support . Its massive magnet rests comfortably on it. A piezo tweeter is electrically connected in parallel and in phase with the subwoofer. There is no X-over. The tweeter also sits on the floor [see close-up]. It beams its output at the cone so that its output bounces back to one's ear. The separation between the erect subwoors is ~18 inches. My head rests on the book [Chemistry] which is ~4 inches high off the floor. This roughly aligns my ears with the center of the sub's dustcaps.
The dual voice coil [8 Ohms each; connected in parallel] subwoofer is sold by MCM Electronics part number 55-1465. Has a 93 dB SPL and a 24 Hz-3.5 KHz frequency range. The piezo tweeter is a Pyle Pro model PSN1167 also sold by MCM. It has a 93 dB SPL and a 3.5 KHz-20 KHz. range.
If one uses a voltage source amp [It is OK ] instead of a TCA, a 30 Ohm resistor must be put in series with the piezo tweeter to prevent the VCA from singing spontaneously. The cones facing each other in this [VCA] application will behave as microphones!. The VCA will thus enforce correction by cancellation. It will sound different from the setup using a TCA.
The dual voice coil [8 Ohms each; connected in parallel] subwoofer is sold by MCM Electronics part number 55-1465. Has a 93 dB SPL and a 24 Hz-3.5 KHz frequency range. The piezo tweeter is a Pyle Pro model PSN1167 also sold by MCM. It has a 93 dB SPL and a 3.5 KHz-20 KHz. range.
If one uses a voltage source amp [It is OK ] instead of a TCA, a 30 Ohm resistor must be put in series with the piezo tweeter to prevent the VCA from singing spontaneously. The cones facing each other in this [VCA] application will behave as microphones!. The VCA will thus enforce correction by cancellation. It will sound different from the setup using a TCA.
Attachments
The subwoofer is wimpy in this application. It is bare like a turtle outside its shell. Its direct output [towards the ear] and that reflected from the piezo tweeter are just right for a good tonal balance. This combo loudspeaker is capable of high sound pressure to literally "blow one's mind/brain". Surprisingly, it is a precise brute which is easy and fast to assemble and dismantle. A "breadboard" loudspeaker of sorts. Best regards.
I have a Threshold S150 [voltage source amplifier or VSA] which is my reference. This 20 year-old is a testament to the genius and excellent craftsmanship of Mr. Nelson Pass. Are the floor 'loudspeakers -pseudo headphones' I described above worthy to be driven by this superb amp? Why not? In this S150 application, I am assessing the performance of this hybrid loudspeaker system with an excellent performing amplifier. In a second comparative application I replaced S150 with a Class A transconductance DIY amplifier. Both amplifiers do not use corrective overall loop feedback. The attached [refined] schematic shows the experimental set up. One voice coil [shown as #1] is driven [the load] by either the VSA or the TCA. Voice coil #2 is a floating power generator which independently drives the piezo tweeter. Both voice coils simultaneously travel in the magnetic field. But; voice coil #2 piggy backs on the travel of voice coil #1 in the field. The orientation of the loudspeaker drivers on the floor is the same as described above. The key findings were:
- The hybrid loudspeaker sounded great with VSA and TCA. Great means pleasing to my ears, and detailed
- The tonal balance of the hybrid loudspeaker due to VSA was richer in the low end than the high end.
- By contrast the tonal balance of the hybrid loudspeaker due to TCA was richer [and quite detailed] in the mid -high end than the low end.
- The hybrid loudspeaker is fully acceptable for music listening.
Serendipity at work! Refer to the pdf in the above thread. What is the fidelity of the power signal emanating from coils #2; say with Threshold S150 driving coils $1? You guessed it; Hi. I used GRADO SR80i [coils #2]for this experiment. I was not laying down on the floor with my head between the erect subwoofers. To my surprise, GRADO sounded superb; full range, spacious and clean. I have earbuds which are shy in the bass. I stuffed'em in my ears, laid on the floor with my head between the subs. The music was full range. Bass and treble were strong and detailed. Ditto with a a low-cost pair of headphones [also bass shy] which sat on the outside of my ears. Here is the value of this set up:
- Easy to implement and low cost too.
- I created a Hi Fidelity [noise-free] headphone port for S150
- No DC offset. Headphones are protected.
- Why build or use a dedicated headphone amp? The existing power amp is more than fully adequate.
- High impedance headphones [e.g. 600 Ohms] will be easy to drive. You have a powerfull amp.
- Extends the frequency range of ear buds, and over-the-ear headphones.
Moving Coil Transconductance Headphone Driver
What's new and interesting? Do you have a Transconductance Amp [TCA] ? Mr. Pass [www.firstwatt.com] has popularized them. The output stage of a TCA [a la Pass] is generally the opposed drains of MOSFETs. There is not a loop feedback [to the front end] which lowers the desirably [and needed] high output impedance of the TCA. Please consult the attached schematic for the following discussion. A TCA drives one voice coil of a two-voice coil subwoofer [12"]. The second coil moves [has to] in a synchronous manner with the energized first coil connected to TCA. This second coil is the "Moving Coil Transconductance Headphone Driver [MCTHD] . The headphone is the load to this second coil and is connected in parallel [with coil #2]. The subwoofer driver is not enclosed. In my experimental setup it hangs freely from the ceiling and out of the way. Take a look at the 3 graphs in the attachment. The top one is the impedance curve of the first coil [or voltage drop across it = Vo] and is typical of any woofer. The one below it is the impedance curve [and also voltage drop across it] of the second coil loaded with the headphone. It has the same characteristic shape of the top one for coil #1. This is the important part. The headphone is driven by a signal of the indicated shape which is primarily the impedance curve [or voltage across it] of coil #1. There is a boost in the low end between 100 Hz down to 20 Hz. There is also a gradual [and substantial] boost of the mids and highs. I have a pair of GRADO SR 80i headphones. They sound totally different [dull] from the situation of being driven the normal way with a voltage source amp. They came alive when driven by MCTHD. The highs are brilliant and the low end is well-defined but light and tight. I found the highs too bright [strident] for my taste. So I toned them down with a 0.1 uF polypropylene cap in parallel with each headphone. Thus I made my new and improved pair of headphones by manipulating the drive signal to them.
Note that a faint sound emanates from the subwoofers which in my set up are ~10 feet away from where I sit. The headphones sounded mostly the same with me in the room with the hanging subs and outside the same room with its door closed.
Treat your ears to new flavor of music.
What's new and interesting? Do you have a Transconductance Amp [TCA] ? Mr. Pass [www.firstwatt.com] has popularized them. The output stage of a TCA [a la Pass] is generally the opposed drains of MOSFETs. There is not a loop feedback [to the front end] which lowers the desirably [and needed] high output impedance of the TCA. Please consult the attached schematic for the following discussion. A TCA drives one voice coil of a two-voice coil subwoofer [12"]. The second coil moves [has to] in a synchronous manner with the energized first coil connected to TCA. This second coil is the "Moving Coil Transconductance Headphone Driver [MCTHD] . The headphone is the load to this second coil and is connected in parallel [with coil #2]. The subwoofer driver is not enclosed. In my experimental setup it hangs freely from the ceiling and out of the way. Take a look at the 3 graphs in the attachment. The top one is the impedance curve of the first coil [or voltage drop across it = Vo] and is typical of any woofer. The one below it is the impedance curve [and also voltage drop across it] of the second coil loaded with the headphone. It has the same characteristic shape of the top one for coil #1. This is the important part. The headphone is driven by a signal of the indicated shape which is primarily the impedance curve [or voltage across it] of coil #1. There is a boost in the low end between 100 Hz down to 20 Hz. There is also a gradual [and substantial] boost of the mids and highs. I have a pair of GRADO SR 80i headphones. They sound totally different [dull] from the situation of being driven the normal way with a voltage source amp. They came alive when driven by MCTHD. The highs are brilliant and the low end is well-defined but light and tight. I found the highs too bright [strident] for my taste. So I toned them down with a 0.1 uF polypropylene cap in parallel with each headphone. Thus I made my new and improved pair of headphones by manipulating the drive signal to them.
Note that a faint sound emanates from the subwoofers which in my set up are ~10 feet away from where I sit. The headphones sounded mostly the same with me in the room with the hanging subs and outside the same room with its door closed.
Treat your ears to new flavor of music.
I did so some 35 years ago and used eliptical FR speakers. Had to tweak air permeability of the earmuffs for best bass response.
I've seen a interesting project in the russian "Radio" magazine. Can't remember if it was orthodynamic or ESL. Must do a search in the basement.
What effect will have the intense magnetich field of the speaker magnets on blood sirculating in ears and brain? Is blood magnetical?
Antoinel Did you licenced your nice helmet phones from Jecklin? ;-)
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Is Jecklin Dr. Jeckel? Hahaha. I believe the magnetic field of a loudspeaker is mostly focused in the voice-coil gap. Other loudspeakers may have a magnetic shield. Blood has Iron in the 2 and 3 + oxidation states [in the protein Haemoglobin]. It is paramagnetic and is influenced by magnetism. I did experiments in college using transition metal solid compounds in an intense and localized magnetic field to determine whether the valence electrons in the D- orbitals of the metal ion were high or low spin. I believe the answer had units of BM [Bohr Magneton].
Please add more details and ask more questions. Maybe the setup improves the frequency response of hearing. Would'nt this be something?
It may be beneficial as you mention above. In a second experiment, the tweeter [piezo and an 8 Ohm Pyle Pro electrodynamic] were vectored perpendicular to the subwoofer [minimum Doppler]. Got fully satisfactory results too. I also measured SPL in this pseudo enclosure with a Radio Shack "Realistic" model analog meter. For a realistic and comfortable listenning experience, the meter [C-weighting and Fast] registered 60-75 dB with occasional peaks at 80 dB. I believe these values are safe during an hour worth of music enjoyment.
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