highlandsun

Audio and data MDs have the exact same disc format. There is a status bit on the read-only TOC that tells what kind of disc it is; this is the only difference. The disc sectors are 2352 bytes. In data mode, 2048 bytes are used for data and the remaining 304 bytes are used for checksums/ECC bits. In audio mode only 12 bytes are used for checksum/overhead. This is why calculating the capacity gives you two different results for data vs audio. In data mode the system acts like any other SCSI hard drive, there is no compression performed unless the host operating system adds it itself.

I've never heard that before but it makes sense. I have a video (65MB, DivX) of a concert I just played a few weeks ago; my brother shot the video on his Sony Digital-8 camcorder and I also recorded using my SoundProfessionals binaural mics. I got the video into my computer over Firewire, no problem there. The audio went from my MZ-N10 analog out to my JB920 home deck, which passed it thru to its digital out, which I recorded thru USB on the PC. It took me some effort to synchronize the MD audio with the video, particularly since there are cuts in the video. (The gig is primarily me on fiddle and this extremely talented oboeist, playing Irish tunes together, with guitar and harp accompaniment.) I think the result came out well, even if the video is ... erratic. http://24.126.120.178/buttonw/projectA.avi

In fact when NetMD is used to transfer an SP track it actually transmits uncompressed audio to the NetMD unit. The reason it is limited to LP2 quality is because Sony's software only stores music in ATRAC3 format. You can program the hardware directly and send uncompressed audio to the NetMD unit.

Yah, would be great. Of course the DCM1 camcorder can take 4500 still shots on a single MD2, so this idea already exists, really.

Be careful, make sure you get a battery module that includes a mic preamp. The basic units that Sound Professionals sells don't include the preamp, you have to get that as an additional option. If your recorder only has line-level inputs, then you need the preamp, not just a plain old battery box.

Only $100? Geeze, to think I paid almost $300 for my USB MD-Port 2+ years ago, and it only supports 44.1khz. I think it's time to upgrade... Would be nice to have a multi-rate digital input. Too bad it only does 16-bit audio though.

I hope you realize that Sony owns 100% of Aiwa, so it's not even a different company, really.

Bit for bit, MP3 is inferior to ATRAC. I can agree with Sony's policy not to record MP3 directly to MD, it'd be a waste of space to get something listenable. Tiny (keychain, etc.) USB/Firewire hard drives are all the rage these days. Sony has totally missed an opportunity to invent/own a market here, and now it's too late.

You still need to do some experimenting/research before you can make this work. DACs come in a variety of flavors, and generally use a raw data format, not the same as S/PDIF data format. If it's raw 16 bit stereo, or raw 24 bit stereo, you will need some extra hardware and logic to get this into a computer's digital audio input port. Generally you may be able to find data sheets for Sony's DACs, so this bit of research shouldn't be too hard. By the way, IC301 is the ADC, part # AK5354, a Google search turns up the data sheet for this part easily enough. It can output digital data in one of two formats. The reason this is interesting to someone hacking a digital output, is you would generally expect that the ADC and DAC in a system both use identical data format. In this case, you have your choice of raw 20-bit words left-justified in a 32-bit per sample data stream, or I2S format. This still doesn't answer for certain what the data format of IC801's DADT output is. The other thing to do here is to look at the components used in previous models; generally the designers will continue to use the same approach over and over again. Find a model that used a discrete DAC, find its data sheet, see what digital formats it accepts. Most likely the DADT output of IC801 will be the same as this.

I've ordered some items thru them before, that no one else offered. Very easy to deal with.

Any AC adapter that puts out DC 6V and at least 500mA will do. Just make sure the plug matches and has the correct polarity.

Let's keep it simple, ATRAC1 (SP) is 292kbps * 75 min = 1314Mb = 160.4MB. MD sectors are 2352 bytes each, carrying 2332 bytes of music per sector, so there are about 70433 sectors per disc. MD-Data sectors are still 2352 bytes each but only carry 2048 data bytes per sector, the rest is checksum/error correction headers. So 70433 sectors * 2K per sector gives 140.9MB. The discs are the same, it's just the way the data is formatted that changes. (But, all MDs have a CD-format read-only TOC that identifies what kind of disc it is. Audio MDs have a different tag on this track than Data MDs.) When 80 minute audio MDs were introduced, no equivalent change was made for data MDs. If you have an MD-Data drive with hacked firmware, you can probably get a few extra megabytes onto an 80-minute MD. I haven't tried it myself, though I may do so, now that I think of it.

EVHShawn - yah, it seems there's a lot of people here talking about how musical a recording sounds, but very few who understand what being "musical" is about... Leland - your experience with the battery life is pretty different from mine, and I don't believe I'm being very demanding in my use. Clearly "your mileage may vary" here.

PCM stands for Pulse-Code Modulation. It is an encoding method, not a transfer method. An optical cable that conforms to S/PDIF spec will carry PCM audio as light pulses. A coax cable will do the same with electrical pulses. An uncompressed WAV file stores PCM audio as a sequence of bits.

On my JB920 I can put it into A/D passthru mode without inserting a disc. Just rec/pause with no disc inserted, and the unit does A/D conversion only. Check your 510 manual, it probably has the same feature.

No, the original MD-Data discs are basically the same as audio MDs. The MD-Data2/MD-View discs that the Discam uses are higher capacity. 650MB vs 140MB.

I really have to wonder what all you guys are doing in your "critical listening" sessions. As a musician, I do a lot of critical listening to my MD recordings because they generally are of live performances that I'm trying to learn from, or they're recordings of my own gigs that I'm critiquing to see where to improve. The fact is, I hear the music, no matter what mode I record in, and that, in the end, is good enough. (I used to use Mono when recording long concerts/workshops, but even when only one person is playing, I find the stereo cues indispensable for helping to distinguish individual notes in complex ornaments. And I always record with binaural mics.) When listening to music just for pleasure, I don't really care about the technical specs. If I did, I would find my FM stereo completely intolerable. All of you folks who are listening to your equipment rather than the music seem to be missing the point. (However, if your hobby *is* listening to equipment, as opposed to listening to music, go ahead. More power to you.) Here's something I've been contemplating recently, which seems to explain some experiences I've had lately - I think there's more to be gained from psychoacoustic compression techniques, but only under a specific condition - you can't enjoy a compressed recording unless you already heard the original performance. In general, brains never lose information, unless they're physically damaged. Every experience you've ever had is indelibly written into your gray matter, and little reminders (scents, sounds etc.) can bring them all back to the surface of your consciousness in full vivid glory. When I listen back to recordings I've made of really great concerts I've seen, I feel the excitement and energy in the air, and hear all the musicality of the concert all over again. I think this is in part because I remember what the original live performance sounded like. I suspect, if I were to hand my LP4 recording of such a gig to a friend, who wasn't present at the original performance, they might find it tolerably entertaining, but maybe lacking in punch. Anyway, since the music is in my head, in full-fidelity, all I need is a reasonably faithful reminder to bring the full experience back. And a binaural LP4 recording does the job admirably.

Note that a 74min pure music CD actually holds much more than 650MB. At 1411200bps = 176400Bps, and 74 min * 60 seconds, you get an actual capacity of 783,216,000bytes. There's about a 13% per-sector overhead when writing data sectors vs audio sectors, which is why 74min CDRs are only spec'd at 650MB for data use. This is also why you can't simply divide the raw audio capacity by a compression ratio to yield an equivalent MP3 size; you have to factor in the data vs audio overhead.

That's too bad... Generally a NiMH charger decides when to stop by noticing that the cell has reached a peak voltage. E.g., the battery has a nominal voltage of 1.2V but a fresh fully charged cell will actually be up at 1.3 or 1.4V. As such, a typical NiMH charger should be able to fully charge any NiMH cell, no matter what its capacity, given enough time. Some chargers have a failsafe timer built in, to cut themselves off after a set time limit, no matter what the voltage reads. I guess you're running into this limit. But it should be perfectly OK to restart the charging process multiple times, because it should still cut off when it reaches the final voltage. However, with a charger designed for a 700mAh battery, it's always going to take a much longer time to charge a 1800mAh battery, because the charger is putting out much less current than it could. (Generally a slow charger charges at C/10 rate, to achieve full charge in 10 hours. So for a 700mAh battery the charger would be designed to put out 70mA. But for an 1800mAh battery it should be charging at 180mA instead. It would take the 70mA charger almost 26 hours to bring the 1800mAH battery up to full charge. Faster chargers may charge at C/2 or C or higher rates, but still the 1800mAh battery will take 2.57 times longer than the 700mAh battery.)

sigh... Speaking from the experience of hacking the MDH-10 (MD-Data drive) firmware, it's very unlikely that Sony left any avenues open in the released product. The TOC resides on a reserved set of sectors on the disc, so TOC sectors can never be confused with music (or data) sectors. (I already tried that, believe me.) Also, TOC, music, and data (if you care) sectors all have different block sizes. More specifically, while there are 2352 bytes per physical sector, there are header bytes, checksums, etc. that vary in length such that the data payload is different for each type of sector. A data sector only holds 2048 data bytes, the remainder is header and checksum. A music sector has 2332 music bytes, with only 20 header bytes. A TOC sector has something like 2306 data bytes. (Or is it 2308? I've forgotten, it's been a while...) To address the specific point - on the MD-Data drives, there was a specific set of SCSI commands ReadUTOC and WriteUTOC for dealing with the MD TOC, separate from the regular SCSI Read/Write commands. And the regular Sony firmware explicitly prevented the SCSI Read/Write commands from accessing music or TOC sectors, they could only be used for data sectors. It doesn't seem that NetMD's protocol is at all related to SCSI or SBP2 (which would be the most logical first choice) but you never know... (I believe) the only way in will be to dump the contents of the firmware, disassemble it, and then rewrite it. For the MDH-10 and MDM-111 drives, Sony at least included a rewrite facility in their firmware. You just needed to figure out the correct SCSI command sequence to write the new blocks. It helps to have the service manual for the devices, to give you a clue about what you're working with. For the MDM-111, since it was a desktop PC device, the work is a bit more straightforward since you can reprogram the firmware using a garden-variety EEPROM programmer. For the MDH-10 it's more pricy because it's a portable device and uses 3V parts. I haven't seen a service manual for an MZ-N10 but I'd guess it may even be using 2.5V logic. I don't have an EEPROM programmer that supports these low voltage devices... The easiest route may be to obtain a NetMD home deck, like the 480, 780, or 980. Most likely they will still be using 5V logic devices. It's highly likely that there is a USB command for rewriting the unit's firmware. They know that they never get it quite right on the first try, and there's always little bugs to fix. The MDH-10 went through some 21 firmware revisions. The MD-Discam was reflashable just by "booting" an appropriately encoded MD-View disc. I'd guess that every device they currently sell is shipped with rewritable firmware...

I've been using a set of SoundProfessionals binaurals in croakie mount for 4 years or so. They're terrific, and everyone who hears the recordings is always amazed at how realistic and clear the music sounds. (Being a Celtic musician, the only stuff I record is live traditional stuff, so extreme sound levels aren't usually an issue.) I've recorded concerts, band rehearsals, jam sessions, masterclasses, etc... and they're all crystal clear and 3-D. It's especially helpful when you're trying to dissect/post-mortem a gig and find the mistakes...

JVC KD-MX3000 head unit - single-DIN, single slot that plays both CDs and MDs. I wish they had released a newer version with MDLP but they appear to have abandoned this player mechanism in their new offerings. I've had this for 4 years or so already, really love it. But now I'm having to use the AUX input to feed MDLP tracks from my MZN10. Oh well.

If you attempt to commercially market the results of your hacking, you can expect Sony to do unkind things to you. If you go opensource/freeware, they may still do so. You'd need a lot of powerful friends to survive the experience.

Yah, 6-7 years ago Sony released SCSI-based MiniDisc Data drives. They need to be hacked though before you can read/write music discs. This is really gross, but I've done "high speed" transfers to PC by playing back on my JB920 at 2x speed. Keep the sample rate high on the PC when recording, and change it back to a normal rate later. Naturally you'll lose most of the high frequency content depending on how good your audio gear is, but when you're in a hurry it works.

My battery life definitely seems very low. However, turning off the internal battery means your internal clock will shut off too. One of the main things I like about these MDs is the automatic date/time stamp, and if I have to set the clock all the time I'm gonna be real annoyed.