I am wondering, if it is possible to build an "ear speaker" like the AKG K1000 or some of the Stax with easily obtainable FR driver?
For those not familiar, this is how AKG K1000 look like.
It is basically open baffle full range speakers. You can call it "super near field listening" if you like.
It doesn't have to be that small or sleek. But to keep the weight and size reasonable, it can not have a speaker box. The question is, can the full range drivers out there achieve a decent frequency response when used like this? I imagine bass would be a problem, the K1000 above is reputed to be light in bass.
I'd appreciate if you guys can point me in the right direction on which drivers to look into, hopefully something affordable.
For those not familiar, this is how AKG K1000 look like.
It is basically open baffle full range speakers. You can call it "super near field listening" if you like.
It doesn't have to be that small or sleek. But to keep the weight and size reasonable, it can not have a speaker box. The question is, can the full range drivers out there achieve a decent frequency response when used like this? I imagine bass would be a problem, the K1000 above is reputed to be light in bass.
I'd appreciate if you guys can point me in the right direction on which drivers to look into, hopefully something affordable.
There are two distinct versions of the k1k: bass light and bass heavy.
Having heard both (and having a heavy version sitting here at my feet) I can tell you that the bass heavy pack a real punch in the low end of things.
I'd be very interested in a miniature fr with similar capabilities to the drivers in these.
Having heard both (and having a heavy version sitting here at my feet) I can tell you that the bass heavy pack a real punch in the low end of things.
I'd be very interested in a miniature fr with similar capabilities to the drivers in these.
I have no info on the exact driver size, But from the look of it, it looks like 1-2" (2.5-5 cm)
6moons audio reviews: Stefan AudioArt hard-wired AKG K-1000
Towards the bottom of the page, you can see a simple circuit. Anyone has a clue on what it is? Low pass filter?
6moons audio reviews: Stefan AudioArt hard-wired AKG K-1000
Towards the bottom of the page, you can see a simple circuit. Anyone has a clue on what it is? Low pass filter?
Oh sorry, how could I miss that!
I once had a pair of W3-871s' breaking in on baffles made out of covers of empty CD stacks (basically plastic 13cm diameter 10cm long tube with a driver at one end stuffed tightly with natural wool). I listened to them "extreme near field" one night, because everyone else were sleeping. I was really amazed how low those went when held just a few cm away. That got me basically the same idea of design. Those massive shielded 3-inchers are not the type of driver you'd want for this kind of application tho, so I experimented with little 1-2" pc speaker drivers in cardboard and plastic baffles to get an idea of the problems and limits of the concept. I was most worried about the back wave traversal time issue similar to open baffle, but when the driver is that close, it's really different.
If I'd try this with real applications in mind I'd look for 1-2,5" lightweight fullrangers with relatively small magnet size to Sd ratio that could handle the lowest point of your chosen bandwidth.
I once had a pair of W3-871s' breaking in on baffles made out of covers of empty CD stacks (basically plastic 13cm diameter 10cm long tube with a driver at one end stuffed tightly with natural wool). I listened to them "extreme near field" one night, because everyone else were sleeping. I was really amazed how low those went when held just a few cm away. That got me basically the same idea of design. Those massive shielded 3-inchers are not the type of driver you'd want for this kind of application tho, so I experimented with little 1-2" pc speaker drivers in cardboard and plastic baffles to get an idea of the problems and limits of the concept. I was most worried about the back wave traversal time issue similar to open baffle, but when the driver is that close, it's really different.
If I'd try this with real applications in mind I'd look for 1-2,5" lightweight fullrangers with relatively small magnet size to Sd ratio that could handle the lowest point of your chosen bandwidth.
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Thanks guys for your inputs. 
I have never done this before, which of these do I want? And let me know too if you have other recommendation.
Aurasound NS3-193-8A1 3"
Speaker Building Supplies from Madisound
Dayton ND65-8 2-1/2"
Dayton ND65-8 2-1/2" Aluminum Cone Full-Range Driver 8 Ohm 290-206
Peerless 830986 3"
Peerless 830986 3" Full Range Woofer 264-1056
Tang Band W3-532SQF 3"
Tang Band W3-532SQF 3" Full Range Speaker 264-910
I have never done this before, which of these do I want? And let me know too if you have other recommendation.
Aurasound NS3-193-8A1 3"
Speaker Building Supplies from Madisound
Dayton ND65-8 2-1/2"
Dayton ND65-8 2-1/2" Aluminum Cone Full-Range Driver 8 Ohm 290-206
Peerless 830986 3"
Peerless 830986 3" Full Range Woofer 264-1056
Tang Band W3-532SQF 3"
Tang Band W3-532SQF 3" Full Range Speaker 264-910
looks like a zobel or impedance flattening network in the K1000, I've done a recable some years ago now but I wasnt so curious as I am now and if I checked I didnt write it down. the headphones have 120ohms impedance and its unlikely the drivers themselves are responsible for that. strangely in the many threads and guides on these great headphones, i've seen many photos but its never really discussed exactly what the values are, not even in the service manual.
strange, even Kevin Gilmore and Fitz havent mentioned anything about these passives, when talking about impedance matching in relation to choosing, or building the best small power amps. The 2 parts appear to be a single SMD ceramic cap and single SMD film resistor. Perhaps theyve talked about it over at headwize, havent checked those threads and the members over there are in general more inquisitive about what really goes on inside their gear than at HF. Surely wink would know Tom? or do you?
people have soldered directly to the posts for recables, so the network is either in parallel, or if its a filter its out of the audible range, because nobody has mentioned anything but the normal silver = brighter, copper = more luscious and warm cliches after recables
wouldnt you be better off with planars Navyblue? what are you going to drive these headphones with? at 8ohms they arent going to be your average headphone load. its hard to know which of the drivers you have listed would be best. Most will rely on some sort of cabinet loading to get full bass response wouldnt they? on surface level the peerless or Dayton would be my choice, with the peerless being favored for better bass extension, somewhat smaller size and lower distortion. hard to tell though, the scale on the graphs in each datasheet are different, you could think the dayton was much better if you didnt realize that, as the response looks flatter. the peerless have about 4x the sensitivity as well (~6dB more)
since you arent going to be taking these with you anywhere, have you considered building them into some sort of chair on either side of the head that way? you could build a little helper sub underneath
strange, even Kevin Gilmore and Fitz havent mentioned anything about these passives, when talking about impedance matching in relation to choosing, or building the best small power amps. The 2 parts appear to be a single SMD ceramic cap and single SMD film resistor. Perhaps theyve talked about it over at headwize, havent checked those threads and the members over there are in general more inquisitive about what really goes on inside their gear than at HF. Surely wink would know Tom? or do you?
people have soldered directly to the posts for recables, so the network is either in parallel, or if its a filter its out of the audible range, because nobody has mentioned anything but the normal silver = brighter, copper = more luscious and warm cliches after recables
wouldnt you be better off with planars Navyblue? what are you going to drive these headphones with? at 8ohms they arent going to be your average headphone load. its hard to know which of the drivers you have listed would be best. Most will rely on some sort of cabinet loading to get full bass response wouldnt they? on surface level the peerless or Dayton would be my choice, with the peerless being favored for better bass extension, somewhat smaller size and lower distortion. hard to tell though, the scale on the graphs in each datasheet are different, you could think the dayton was much better if you didnt realize that, as the response looks flatter. the peerless have about 4x the sensitivity as well (~6dB more)
since you arent going to be taking these with you anywhere, have you considered building them into some sort of chair on either side of the head that way? you could build a little helper sub underneath
I would think a Zobel would make sense, may be some speaker amp don't like 120 ohms? However I would think that AKG made the the drivers 120 ohms.
I pretty much don't know any one.
By planar, do you mean that there are planar drivers suitable for this? I really have no idea what is out there. I see some planar tweeter, but I suppose those are no good?
The 3" drivers do seem a bit too big and heavy to be mounted on head. If I am really going with this and it doesn't work out, my plan B would be to turn them into open baffle desktop speaker. I insist on open baffle because I am lazy and cheap.
I also figured amping it would be a problem as it won't be suitable for use with headphone amps or typical speaker amps. I ruled out all the 4 ohms drivers, but it is still 8 ohms. I suppose ideally I would need one of those flea watt speaker amp. If I were to parallel 4 of them to get 32 ohms, would a headphone amp drive them loud enough for use as desktop speakers?
I wouldn't worry about driving them. Modern solid state headphone amps are just low power speaker amps. Output impedance is very low. Though, a 45 SET amp would be very nice for this.
A close distance, don't need dipole compensation. Most likely no passive components would be needed at all. Don't need Zobel.
All you need to do is pick a suitable driver. I would attach it to a construction helmet or a chair.
A close distance, don't need dipole compensation. Most likely no passive components would be needed at all. Don't need Zobel.
All you need to do is pick a suitable driver. I would attach it to a construction helmet or a chair.
Output impedance is unlikely to be an issue, but would the current draw be a problem? I imagine the output transistor's heatsink and the PS has to be up to the task, but it might work. I have a Beta 22 that I intend to get rid of, may be I have to keep it. I also have a SOHA II and a spud amp that I am working on, those I am not so sure if they can cope, especially the later.
I was thinking of bicycle helmet, but I guess construction hard hat is a better idea.
hmm, methinks you have too much confidence in modern headphone amps, or have a different idea of what is LOW, many designers cover their *** and add resistors to buffer the amp from cable capacitance and short circuit. many application notes still call for it too. the B22 will be fine though
also we are talking about low efficiency and low load impedance here
perhaps they did make them 120ohms, depends if they used off the shelf for the initial design or not, i'm thinking Zobel too.
aahh haha sorry I did word that a bit funny. Tom is nattonrice, the other Aussie who posted here in this thread just yesterday about having Justins bass heavy K1K at his feet, I was asking him if he knew the details of the extra components, being a curious and quite proficient Diye. Justin and wink are big K1K fans so thought they might know tooI pretty much don't know any one.
I wasnt asking if you knew them =D
yep planar drivers for your headphones, they are usually pretty light and compact, many tweeters will be fine and will have decent bass at such low power and mounted so close to the ear, you'll just find that the bass response droops, or they are higher impedance at low frequencies, again fine at low levels. not all will, but worth looking into. HE6, HE5, LCD-2/3 are all planars
haha good back up planThe 3" drivers do seem a bit too big and heavy to be mounted on head. If I am really going with this and it doesn't work out, my plan B would be to turn them into open baffle desktop speaker. I insist on open baffle because I am lazy and cheap.
if you parallel 4 of them, you'll lower the impedance, not raise it. the result of 4 parallel 8R drivers would be 2ohms, but it would be very efficient. yeah your beta (balanced beta? that could be a bit touch and go) will probably be fine with single 8ohms drivers, some amps would struggle a bit.
you might want to increase the bias and lower the rail voltage a touch so you get more class A into the lower impedance. 4 ohms would be pushing it though.
otherwise yeah just grab some ebay chipamp kits
Sorry, I meant series.
My B22 is 3 channels, and not configured for speakers. I also remembered reading that Zobel is needed if intended to drive speakers, but I'll worry about that later.
Back to the driver question... Is Peerless a good driver manufacturer? Does is Tang Band has better reputation?
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