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borjam

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About borjam

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  • Location
    Bilbao/Spain
  • Interested in Sound for Picture
    Yes
  • About
    Bilbaina Jazz Club

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  1. borjam

    Good price on 7506 headphones!

    By “similar sound” I should have said “similar properties”. Both are colored, indeed they wouldn’t be my choice to listen to music (I have HD600 at home for that), but the coloration somewhat helps to focus on details such as compression problems, which makes them useful. The Ultrasone HFI-650 have better isolation but being heavier, bulkier and in somewhat high temperatures you can feel your ears cooking after an hour or two. The confusing thing with Ultrasone is the model proliferation. It’s a young company and there are so many models. And some of their bananas pseudoscience marketing claims about confined magnetic fields and effects on health don’t help. Anyway, the HFI 650 have been for me for several years and I have used them in lots of concerts with good results.
  2. borjam

    Good price on 7506 headphones!

    Yes. But I confirmed they were fake. I am in touch with the LSI Logic staff, at that time I was helping debug some problems in SAS drivers and poking them to do it right And later I could see the real parts with proper Molex connectors. Anyway, not trying to smear anyone. The 7506s I ordered from Amazon.es last week are the real deal. Love them, when I was 16 I had a pair of MDR-v4 and they were very good. Compared to the Ultrasone (HFI-650) the sound is rather similar, with a bit less isolation but, as a plus, being much lighter and comfortable especially in Summer outdoors.
  3. borjam

    Good price on 7506 headphones!

    The worst problem in Amazon is counterfeit products. Several years ago I ordered some internal SAS cables (SAS, the up to date version of SCSI) and despite having LSI Logic (later Avago, now Broadcom) part numbers they turned out to be fake. Worst, I didn't notice that the connectors weren't real Molex parts. When I had to remove the cables (I ordered them for a test, I was developing software for a storage system), to my horror, the connectors stuck like crazy. I needed an hour to destroy the "Moolex" connectors without damaging an expensive IBM SAS backplane. And Amazon are so deeply aware of their counterfeit problem, they didn't complain when I returned a completely ruined pair of cables for a refund. Last week I ordered the 7506 after the recommendations I read on this forum and seems they are not fakes But well, at some point I wondered wether it was wise to order a widely copied product from Amazon.
  4. borjam

    USB-C Connector

    Agreed, it’s too flimsy. At least it’s reversible, I don’t know how many FireWire accidents were caused by reversed plugs.
  5. borjam

    USB-C Connector

    At least in theory it should be as reliable as FireWire. Why don’t you have a look at the system log?
  6. borjam

    You think WE'VE got sync problems?

    Actually it's two different problems The first one is the synchronization accuracy. The second one is a trusted timestamping mechanism that can't be played by the users. I can imagine some cryptographic approaches, but it's a hard problem and huge resources will be devoted to subvert it.
  7. borjam

    Looking for a non audio looking bag for my MixPre 3

    I am using a Lowepro camera bag with good padding, an Event Messenger. I don't remember the exact model though but it may be the 100. https://www.bhphotovideo.com/c/product/893440-REG/Lowepro_lp36461_0ww_Event_Messenger_100.html?sts=pi A bit similar to the Think Tank bag, but more square looking (I think Lowepro have some odd obsession with right angles) and cheaper. It has a feature I like for urban areas. "Switchable" velcro bands for the bag cover. If you enable them it gets really noisy to open. If you disable them then the cover relies only on the typical snap-on latch. I have been considering modifying the bag, my sister in law has a clothes mending business and she's pretty good. In case I go that route I will share the description of course. The bag has been holding a Fostex FR-2LE comfortably (although with some cable bending) and the tiny MixPre 3 almost gets lots inside. I would add two velcro straps to hold it in place and some molle straps to the front.
  8. borjam

    Sound Devices MixPre-3 vs Zoom F4

    Well, the MixPre 3 arrived yesterday. I have only played a bit with it, but WOW! First, the headphone amplifier. I had read all kind of praises, but they fall short. As I was really curious I plugged the recorder to a USB port and I played a good recording I know well. I am happy with my headphones (Ultrasone HFI-650) but I had never heard them like that. I've used them connected to a Metric Halo ULN-2, a Mackie Onyx 1640, my personal mixer (MixWizard 3 14:4:2)... I couldn't believe it. I am only guessing, but seems that these headphones have a low impedance at low frequencies, making them harder to drive for many amplifiers. The MixPre drives them like I have never seen. The poor FR-2LE looked like it was going to catch fire. Some audiophiles would buy a unit just to use it as a headphone amplifier. I remember some got Metric Halo ULN-8 interfaces mostly to use as D/A converters. So I picked up a microphone (AKG SE300B+CK98) and I visited the local wetland to listen to some birds. I also tortured the limiters and HPF, especially with some rough handling of the microphone. At the risk of sounding fanboyesque, even the resistance when turning the faders is perfect. I have read some comments about SD eroding their own market. I don't think that will happen at all. Quite the contrary, I think this low hanging delicious fruit will help them expand a lot. They are delivering the key high performance features at a lower price point but leaving the more specialized ones to the upper series. So, would I be the same with a F4? I don't think so. The limiter and HPF in the analog domain and the headphone amplifier are critical features in my opinion. Now, I am curious. What are SD doing with a 32 bit A/D converter? Adding resolution for low level recordings reducing quantization noise?
  9. borjam

    Ultrasound, IoT and wireless

    I see Note that microphonics exist! Especially old valve equipment could transmit voice if you shouted at it. I have an old Leader grid dip meter here that doubles as an AM transmitter if you shout loud enough! But with modern SMD electronics that's almost impossible, don't worry! Some of them use microwaves although I doubt they can affect your equipment unless you are in the same frequency. So, careful with equipment on the WiFI/ISM 2.8 GHz band. Although I believe that 2.8 GHz detectors aren't common nowadays for obvious reason. At home I have a 10 GHz detector.
  10. In the USA you can use channels 1,6,11. In Europe you have a bit more spectrum available and you can use 1,5,9,13. However, I've seen lately that many routers no longer default to channel 1, they choose a channel semi randomly (or listening for noise). And to make matters worse a lot of people use 40 MHz channels on the 2.4 GHz band, which is a serious problem because a single router will take most of the band. Vodafone at least in Spain is doing that. If you have access to 5 GHz equipment I would really recommend it. There is more bandwidth available, attenuation due to distance is bigger and walls attenuate it much more. Moreover, most cheap routers still don't support 5 GHz, so the band is almost empty. For example: my network has three access points. From them I see 96 SSIDs (network names) in the last 24 hours on 2.4 GHz, just four on 5 GHz. There is a caveat with 5 GHz however. Not all channels are equal. Some of them are meant only for indoor installations and others share spectrum with meteo radars. It means that the access points must listen before starting up the radio (up to 10 minutes) and meteo radar interference can be a problem. And the second problem is, there are "pirate" wireless ISPs all over the world violating regulations, using too much power, etc. Some even show up on weather radars. So, if using 5 GHz outdoors and especially at a somewhat high point always check wether it works properly. This diagram is quite clear. https://en.wikipedia.org/wiki/List_of_WLAN_channels DFS means Dynamic Frequency Selection, which implies that equipment must listen on the frequency for a certain time interval (10 minutes is the last I have observed) before activating the 5 GHz radio. It's mainly meant to avoid interference with weather radars. It can be confusing because many people will configure the AP/router, start it and be puzzled because the 5 GHz network doesn't appear immediately. TPC means Trasmit Power Control. It's a measure meant to encourage frequency reuse. Equipment is supposed to lower power on TPC channels automatically, of course always Except for those problems (generally less frequent than the 2.4 GHz nightmare) my iPad and iPhone can move 300 Mbps over the wireless network without much problem. RF Explorer (I noticed that the brand is already known here) sells a more complete model that can monitor the 5 GHz band. As for security: Stick to WPA2 with AES-CCMP and disable WPS, WPA and especially WEP. Use a complicated password and you won't really have many reasons to worry. Also, not all wireless equipment is equal (suprise!).
  11. Understood. Sorry, I am not famiilar with the FCC regulations and I've seen so many mentions to Part 15 I assumed it covered intended usage. Although I have found this reference: https://docs.fcc.gov/public/attachments/FCC-13-112A1_Rcd.pdf In particular, paragraph 4 says "Any type of unlicensed operation within the 60 GHz band is permitted under these rules, with the exception of operation onboard aircraft or a satellite". The airborne restrictions make sense because airborne transmissions might disrupt inter satellite communications. Hmm sorry to point it out but I don't think it's "fixed inter-satellite" nor "mobile radio location". I think it is "Fixed", "Inter-satellite", "mobile" and "radio location". The equipment I am testing is intended for fixed data links, for instance. Anyway, I was just curious. From my experience so far it seems to be promising for many applications. Especially with the possibility of a very high spectrum reuse and very little interference. It also encourages the usage of very narrow beam antennas, which would reduce interference further. My units, for example, use beam forming arrays with 36 elements. The antenna assembly is a small 20 mm x 20 mm square. Let's see how it develops, I heard about the new 802.11ad wireless networks several years ago and I only could test some equipment this year.
  12. borjam

    Sound Devices MixPre-3 vs Zoom F4

    Thanks Yes, I read about that perfectly wise company policy today while perusing their website. I see also that they have a design ethos different from other companies. At least with the MixPres they have decided to design the user interface around certain expected use cases rather than offer a full set of arbitrary options which would demand more controls making the touchscreen unusable. I hope nobody thinks that I am mad at them because I said "offensive" or I made a "Brazil" pun with their ministerial answer. Not at all, I even ordered the recorder and I am sure I'll be perfectly happy with it even if I must wire an polarity reverse adapter or two. (English is a second language for me, my sarcasm/banter skills can be a bit sub-par).
  13. borjam

    Sound Devices MixPre-3 vs Zoom F4

    So, in order to even the outcome of this thread I ordered the MixPre 3. I see that some of the functions in the F4 are more comprehensive (and it has 4 mic preamps instead of 3) but with the Fostex I've learned how an underspecified headphone output can ruin your day especially if recording outdoors in a windy day. The metering in the MixPre seems to win as well. and after perusing the manuals I think I like the MixPre user interface better. We'll see. Now, if only they added a "phase reverse" button to the channels now that they have crossed the Rubycon of the third menu screen I would be even happier!
  14. borjam

    Ultrasound, IoT and wireless

    Affecting some pre-emphasis circuitry in the audio domain would be possible of course. Sorry, when I read about it affected "wireless" I was confused, I didn't consider the analog noise reduction systems. I stand corrected
  15. I have a working link. It's short, 20 m, but it supports 1 Gbps in full duplex. No packet drops, as I said. The equipment I am using is capable of sustaining that to 100, even 200 m unless there is a heavy hail storm or rain. Yes, my link is short, I had to reduce power to avoid overloading the receiver. The thing is, the high atmospheric attenuation together with the small wavelength really reduces that interference. I could run another link across the same street and my link wouldn't notice. I think you could achieve around 100 m without much problem. Human bodies absorb a lot, of course, but beamforming antennas exploit reflections on multiple surfaces. I don't have power consumption data and in my case it's distorted by the core CPU they need to be able to move 1 Gbps of traffic. Anyway, the power supply is not larger than the older 2.4 and 5 GHz equipment I used. It could be challenging for a small belt clipped wireless transmitter, right. I don't have figures for the current consumption of the RF part. A good aspect of this band, however, is that given the huge bandwidth available you don't need an elaborate coding scheme, which reduces the processing power needed. My link is using QPSK, not even QAM. As for 2.4 GHz, the band is too polluted. When I first tried wireless systems on 2.4 GHz the band was empty. You could achieve 100 - 200 m from laptop to laptop without an access point even. Now I detect around 100 wireless networks in the small street where I live. 5 GHz is better (walls add more attenuation) but it can be a problem with weather radars. https://transition.fcc.gov/oet/spectrum/table/fcctable.pdf Page 61: 59.3 - 64 GHz. RF Devices (Part 15) and ISM equipment (Part 18). According to note 5.138 the 61 - 61.5 GHz band is designated for ISM devices. You can already use the equipment I am trying. It was approved in the USA some months ago. https://fccid.io/TV7WAPG60AD Caveat, I am Spanish, I'm not that familiar with the US regulations but I guess "Part 15" covers wireless microphones.
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