Wikipedia:Reference desk/Archives/Computing/2010 October 25

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

October 25

High Quality Digital Audio Setup for a Home Sound System

I am looking for some advice on purchasing a high-quality audio DAC for an antiquated, but high-quality sound system (a suggestion on a nice ADC would be good too for recording vinyls, etc.). What I plan to do with this is route music from a PC to the stereo system, but high sound quality is a must for this system.

I am wondering if the quality of HD audio that is integrated on the motherboard of all modern PC's is such that it will be sufficient for my purposes (note here that this setup is not for me, specifically, but for my father who is a self-proclaimed audiophile, but does not understand digital systems at all and does not care to learn, so it must please his ears and not mine--which is certainly subjective, but something at or above CD audio quality may suffice). I recall in the past when routing audio from an older sound card that electronic noise was a considerable issue at the time and this would be unacceptable here, so I question whether it's possible at all to use integrated audio and not get that electronic noise (I understand it's not possible to entirely do away with it, but if it's practically inaudible then that's fine), or if I will need an external converter which connects to the PC via USB or S/PDIF.

The sound system in question accepts two different physical inputs: a 1/4" stereo plug or the red and white pair of RCA connectors. Is there any difference in sound quality (possibly lower noise?) between these inputs either?

Does anyone here have any experience with this? -Amordea (talk) 04:45, 25 October 2010 (UTC)

What are you going to use as the source of your music? --80.40.144.68 (talk) 09:01, 25 October 2010 (UTC)

As for the source, probably FLAC's or high bit-rate MP3's (MP3's less likely given they are lossy) or perhaps even raw CD audio (a la disk images). Basically any quality digital format that could be contained on a hard drive. -Amordea (talk) 02:09, 26 October 2010 (UTC)

Basically, any sound-card (including the one built into your computer) will be sufficient. The phrase "hi-fi" is currently (for the most part) an obsolete description: everything sold on the market today is "hi-fidelity." Let me explain: in the "old days" (let's say, 1950s), an audio amplifier would have "imperfections" in its gain characteristics. It might notch out particular frequencies or introduce a certain noise level or so on. The term "High Fidelity" was coined to refer to those audio systems that amplified the recorded sound with essentially no frequency distortion - "faithfully" replaying the recorded audio. In very old systems, this was a huge engineering challenge - tubes and speakers had all kinds of non-ideal characteristics that would interfere with the sound quality in a very audible way.

Ever since the days of solid state amplifiers, the electronic capabilities of an amplifier are way beyond anything any human could hear. Today, cheap transistors have perfectly flat frequency responses from DC to 20 GHz; noise figures are so far below anything an ear could discern; and 44.1 kHz sampled 16-bit digital audio accurately stores and reproduces exactly the original waveform (far beyond any capability of any human audiophile to distinguish). Now, software tuners and graphic equalizers exist to intentionally add imperfections to alter the tone of audio playback so that it can sound identical to the distortion of an old audio system. Let me rephrase this: every cheap, crappy sound-card you can buy is already 16-bit at 44.1 kHz with a flat frequency response. The worst possible quality digital audio system is already "perfect" and "indistinguishable" from original source. (The low-end models will have fewer features, but it's very unlikely they will actually have poor quality). "Professional quality" sound-cards will try to pitch some extra specs - 96kHz audio (which is useless to you and anyone who has human ears); and better latency during recording and pass-through (a spec which I have never independently validated - every sound card I have ever spent money on has always been limited by my computer's operating-system audio-system latency).

Modern "noise" is much more likely to come from a few sources: first, poor-quality digital sources (such as low-bitrate MP3 files) are the biggest culprit. MP3 is a lossy format; it does not perfectly store the original waveform, but stores a similar version of it. At 128 kbps bit-rate, which is reasonably common, I can tell that the sound is distorted (especially if there are high-frequency instruments or wide-band sounds like applause). My oscilloscope can certainly tell the difference between 128kbps and original waveform. But properly produced MP3 files, (let's say, 192 kbps or higher) are for the most part indistinguishable from an uncompressed recording.

The second possible source of noise is "coupling" - electromagnetic interference, in the form of power line hum, and in some cases (especially if your sound card is cheap and inside a computer) you can hear digital signal noise leaking on to the audio lines. On my laptop, whenever there is activity on the front-side bus, I can hear a faint high-pitched squeal leak onto the audio line. And on some of my speaker-setups, if I am sloppy with my wiring, an audio cable will loop around an AC power cable, and I can hear the 60 Hz hum if I turn the volume up pretty loud. Regarding choice between 1/4-inch and RCA connectors, it is doubtful whether this will make any perceptible difference. (I have used both; I prefer 3.5mm connections because they're small, and 1/4 inch when running long cables because I happen to have a lot of sturdy and long 1/4-inch cabling laying around). Make sure your 1/4 in isn't mono (some old systems, and some current professional-audio equipment, uses 1/4-inch for mono signal exclusively).

It is most probable that the weakest link in your audio system will be software - if you have a crummy sound-card driver, you might hear glitchy playback; if you have poor-quality sound files with sloppy compression, you will probably be able to hear squelchy squealy noises during playback. But I wouldn't spend much money on a sound-card, unless there's a specific feature you need - say, digital/optical audio connection, or 7.1 channel surround-sound. I'm of the belief that 2-channel (stereo) sound is sufficient for most "entertainment" purposes; some movies benefit from a rear or side channel, but most of the time, extra channels are gimmicks. Nimur (talk) 18:06, 25 October 2010 (UTC)

Very informative. Thank you!

The "coupling" you mentioned is perhaps my biggest concern about the integrated audio. I personally wouldn't be able to hear it given that my hearing is rather poor now, but my father might and if he does, he would simply not use the system (and I already have to overcome the hurdle of his suspicion of digital audio--even though he listens to CD's, which I have pointed out is digital--and certainly do not want to add to the unreasonable stigma he has against it).

The system is just two-channel audio (it is from the 1970's), so I have no need for the bells and whistles of surround sound. What sound card would you recommend? Do you think the integrated audio (on say an Intel 945G motherboard in an AcerOne netbook) would be sufficient and would not produce any noticeable hum or static?

One problem I've noticed with this particular setup (routing audio from the netbook to the stereo amplifier) from what I can hear is that the bass is too much, which I can compensate for by turning the bass volume way down, but that is a rather inelegant solution. I am wondering if it has something to do with having to route the sound through the headphone/speaker port. Would I need a sound card with a line-out port for this purpose? I frankly don't know the difference between the speaker port and a line-out. -Amordea (talk) 02:09, 26 October 2010 (UTC)

I would suggest that your integrated audio on the netbook is perfectly fine for these purposes; test it out and see if it's suitable. Regarding "too much bass," I use WinAMP. WinAMP is zero-cost (but not open-source) software; it has an interesting historic legacy and a spectacular user-interface. Among other features, it provides a software graphic equalizer that you can use to set the bass-levels and other tone quality to your liking. If you prefer free software (as in Linux), Rhythmbox, Amarok, and others exist to provide the same functionality. More technical audiophiles may enjoy Audacity, and jackd. The software I listed above will range in user-friendliness and expertise-requirements from "trivially easy" to "professional audio programmer", so you and your father can decide where you fall on the spectrum. Nimur (talk) 02:30, 26 October 2010 (UTC)

And regarding "speaker" vs. "line-out" - on many computers, the difference is that "speaker" is amplified, and "line-out" is not; but the amplification is usually pretty small to the point of nonexistence. See our article on line level for more on this detail. "In theory" a line-out should never be connected to headphones; but in practice, modern electronics protect against this with digitally-controlled impedance matching (so you usually have nothing to worry about). Nimur (talk) 02:33, 26 October 2010 (UTC)

I recommend for you to use a digital audio editor instead of a media player. I simply connect my XP desktop to my stereo system and use this player/editor. Sometimes I connect RCA connectors to a TV's audio line outs, record the sound of a concert program, keep it in my PC as an audio file and listen to the file on the stereo. Oda Mari (talk) 07:55, 26 October 2010 (UTC)

VBA Question Part 3

If I want to run multiple SQL INSERT INTO queries, in VBA; What should I write to distinguish between queries? I've tried newline but that doesn't work in VBA. I've tried running the queries like this;

strSQL = ""
strSQL = strSQL & " INSERT INTO [CCF Static]([Main Table ID], [Integrations Team Member1], [Sales Team Member1], [Merchant Name1], [Merchant Type1], [Partner1], [Tier1], [Merchant Sector1], [Date Entered Into System1])"
strSQL = strSQL & " SELECT [ID], [Integrations Team Member], [Sales Team Member], [Merchant Name], [Merchant Type], [Partner], [Tier], [Merchant Sector], [Date Entered Into System]"
strSQL = strSQL & " FROM [Master Query beta 1]"
strSQL = strSQL & " WHERE [Master Query beta 1].[ID] = DATE() & "" & DATE()-1;"
MsgBox strSQL
DoCmd.RunSQL strSQL

strSQL = ""
strSQL = strSQL & " INSERT INTO [Brands]([Customer Name], [Merchant Sector])"
strSQL = strSQL & " SELECT [Merchant Name], [Merchant Sector]"
strSQL = strSQL & " FROM [Master Query beta 1]"
strSQL = strSQL & " WHERE [Master Query beta 1].[Date Entered Into System] = Date() & "" & Date()-1 AND [Master Query beta 1].[Merchant Type] = [PSP] OR [Merchant] OR [Reseller] OR [Sole Trader];"
MsgBox strSQL
DoCmd.RunSQL strSQL

But I get the following error: 'Run-time error '3075':

Syntax error in string in query expression '[Master Query beta 1].[ID]= DATE() & " & DATE()-1;'.

Any idea why? Panyd^{The muffin is not subtle} 10:35, 25 October 2010 (UTC)

Well, this is just a problem with how you've formatted the SQL string, or maybe rooted in a misunderstanding about how to use SQL. (It's not a VBA problem.) Look at what it's spit back at you: there is a single, unmatched quotation mark that you've added there. Why? That's not going to be valid SQL. A general rule with this stuff is to first just have the SQL string output (e.g. with a MsgBox or by using Debug.Print) to see if it makes sense to begin with, before worrying about the VBA side of things. As it is you have a malformed SQL query, and I'm not at all sure what you think it shuld be doing. DATE() & " & DATE()-1 doesn't make any sense to me at all.

If you are trying to add a space, you need to properly format the question marks in the string so they are passed (as escaped characters) to the query. In VBA this is through double-quotations, so "" will produce " in the final query, and """" will produce "". --Mr.98 (talk) 14:20, 25 October 2010 (UTC)

Note that building up SQL commands in plain strings is dangerous; see SQL injection. Paul (Stansifer) 16:03, 25 October 2010 (UTC)

Though I don't see any opportunities for injection attacks in the above. And it's not too hard to protect against said attacks — it just requires passing the strings through a screening filter first. Though I will agree that not knowing SQL very deeply and also building up SQL commands in plain strings in a language you are not terribly comfortable with probably is a good recipe for danger! Assuming that you are going to have other users using it, anyway. --Mr.98 (talk) 16:26, 25 October 2010 (UTC)

Just as an aside, and to reiterate what I said above -- I assume you are using MS Access. If you are not totally comfortable with SQL, work out the SQL statement (with dummy date if necessary) first in Query view, and then, after you're sure that the SQL works, translate it into the VBA strings. Otherwise you are entangling two very different possible sources of error (VBA and SQL) together in a way that is hard to tease out, especially since Access gives extremely cryptic error messages regarding SQL statements (as you've seen). Just a suggestion from a long-time Access programmer. --Mr.98 (talk) 18:57, 25 October 2010 (UTC)

Thank you guys so much. You've hit the nail on the head, I don't know what I'm doing, your advice is appreciated. I'll go back to building this in Query view. Thanks again. Panyd^{The muffin is not subtle} 09:41, 26 October 2010 (UTC)

what are functions of DATABSE SERVER..??

what are functions of DATABSE SERVER..??—Preceding unsigned comment added by Lokesh.mavale (talk • contribs) 17:34, 25 October 2010 (UTC)

See database server.—Emil J. 17:47, 25 October 2010 (UTC)

Od Dear - i'm scared to ask but - how do I choose what new PC or Laptop to buy?

Please understand - I am not a techie. I am 63, and have used IT in Scotland for about 20 years. I can use the whole Microsft Office Suite - professional - and use the PC daily, mainly for storing digital pictures (also copied to external hard drive), plus the Internet to keep in touch via e-mail but notsomuch facebook etc. I buy and browse online and have never had a problem. I bank and invest and study the markets online. I also like to convert digipics and music to picture vids for which I have the software. Trouble is - like me - my kit is getting old - and slow - and I keep getting messages that such and such a file is missing or corrupted - which leaves me cold. So the question is - and please forgive me - which Santa Claus do I trust? I am mid 60's, reasonably put-together, not wanting to waste my life on video games, but wanting to stay informed, avoiding hard mail and bugs, worms, trojans, viagra, and anti-death-offers, store pictures and music, and not sit around any longer than the kettle takes to boil. So do I shop online, buy a second-hand system (I don't need all the accessories such as keyboards etc.), and I will NEVER use a laptop on the Beach as I saw some youngsters doing last weeek in Spain - (sad Bar Stewards), or do I walk into PC World and say, "Please help me" - and then get ripped off? Thanks. Oh - Budget? Middle range I suppose - I don't want anything I will never use during the next 5 years or so. Thanks again. 92.30.211.53 (talk) 19:32, 25 October 2010 (UTC)

There are online buyers' guides — if you google desktop computer buyers guide then a number will appear — I would ignore the buyers' guides that are more than about 9 months old. Computer Shopper is a US publication with a "Desktops" section that might be useful, and Consumer Reports is a respected US nonprofit that does computer reviews, though its detailed ratings are behind a paywall. Personally I would get a machine from a large commodity PC maker like HP or Dell that stands behind their product (or claims to, anyway) with a year of free technical support. Comet Tuttle (talk) 20:33, 25 October 2010 (UTC)

One question is: do you want a desktop or a laptop? Your keyboard and mouse will probably work with the laptop. (You would want to confirm this before choosing the laptop.) The laptop is lighter in weight. It will allow itself to be more easily set up in more than one location, if that seems a plus. I am assuming of course that your present computer is a desktop—I could be wrong about that. Bus stop (talk) 20:43, 25 October 2010 (UTC)

go to your local Apple Store and ask for advice there <smirk> --Ludwigs2 21:13, 25 October 2010 (UTC)

Except you can't use Microsoft Office Professional on a Mac. (And the Office 2008 software is exceptionally buggy on a Mac.) I say this as a Mac user, not a hater. --Mr.98 (talk) 22:56, 25 October 2010 (UTC)

ludwig2's suggesion is good for getting ripped off in my opinion, as you're leaving it up to the salepeople to help you decide, which often resultes in them steering you to the most expensive items, with not neccessarily the best value. look at recent consumer guides for an idea of what to get, as well as for reviews. 70.241.18.130 (talk) 16:11, 26 October 2010 (UTC)

I'm not convinced that you need a new computer. Computer hardware doesn't normally get slower with time; it works like new until it fails completely. If your computer has gotten slower, it's almost certainly a software problem, and those can be fixed for free. Your computer probably came with a "recovery CD" or "recovery partition" or something of that sort, and after you run the recovery process it will be just like new. That means that all of your personal files will be gone—so move them to the external drive first!—and you will have to reinstall any software that you installed yourself. It's a hassle, but you'd have the same hassle with a new computer. -- BenRG (talk) 21:59, 25 October 2010 (UTC)

It's true that all Windows computers I have had do tend to slow down over time — but the original poster may feel that his or her computer is slower because the demands of his or her favorite Web sites may be increasing. Comet Tuttle (talk) 22:54, 25 October 2010 (UTC)

What exactly do you mean by "middle" budget range? 500 USD? 2000 USD? To do what you want to do (use Microsoft Office, edit photos, and access the internet) will not take a terribly expensive computer. How well you can use the internet will be more a function of your internet access than your computer. Your ability to avoid viruses and Viagra ads will be a function of your Antivirus program and Spam filter, respectively, not your choice of computer. I really can't see any value in buying a second-hand system. You can get new computers today at a very reasonable price, and you can be pretty confident that they're going to work well (and, as Comet Tuttle recommended, there are many companies that will offer free tech support and a year long warranty). To be honest, I think that walking into a computer store and telling them what your looking for might be the best bet. In my experience, most people at such places are actually helpful and knowledgeable, and are more interested in getting you to buy a computer that you'll like, rather than the most expensive one. That's just my experience though. I would recommend Microsoft over Apple; not only will you be able to use Office, it will also be cheaper.

I would probably be expecting to pay about 500 USD for a machine (if you get a desktop; laptops will be a bit more expensive) to do what you want; get yourself something with 4 GB of RAM, an Intel Pentium processor, maybe a 500 GB Hard Drive, a DVD read/write drive, and an Integrated Graphics Processor. On the other hand, it's not really that expensive anymore to get a PC that's more or less "top of the line". For under 1500 USD, you could probably get something with 8 GB RAM, an Intel Core i7 processor, a dedicated graphics card, a 1 TB hard drive, and maybe even a drive that can read Blu-ray Discs. This will be a lot more than what you currently are using your computer for, but it will also stand a better chance of being useful for a lot longer. More memory will help speed things up, and will also allow you to do more things at once without as much slowdown (the better processor ought to help with this too, to some extent). It's likely that webpages are going to continue to get more and more complex as time passes (Wikipedia is really the exception to this rule; it's sickening how much junk is on so many sites these days). In addition to requiring a better internet connection, such pages will also demand more memory and processing power. I think that Blu-ray is going to become more and more prevalent in the next few years, so I would strongly recommend getting a computer with a drive that can read Blu-ray discs. Buddy431 (talk) 00:58, 26 October 2010 (UTC)

Pretty much any PC will do all the things you mentioned above. Prices for new PCs start from around £300 for the lowest specification. It is actually quite difficult to buy an off-the-shelf system from a retail store like PC World, without a keyboard, mouse and monitor. If you can spend a bit more, it is worthwhile getting Microsoft Office bundled in with it. Buying from PC World does seem expensive and you are never sure if you are getting a good deal, especially when you notice their prices are identical to other stores like Comet, but the alternative is to buy from a small independant (perhaps on a local industrial estate), or buy online. Even though they often go on about the latest equipment, computer magazines can be useful sources of information about other suppliers even if you don't buy the exact model being reviewed that month. I've bought many Dells and have been pleased with every one of them, though other people here will tell you they would never buy a Dell.

Having said that, an alternative might be to refurbish your old PC. Back-up your documents, photos, emails, etc. Locate all the installation and driver disks. Add some more memory and replace the hard disk drive with a larger capacity one. Then reinstall the Windows operating system and Office and all the driversand other software you need. Download and install all the updates you're offered and put your backed-up data back. You will be amazed how much faster your PC seems. Astronaut (talk) 06:55, 26 October 2010 (UTC)

Thanks to all above responders - I really appreciate all your advice. I am going to print them off and consider all the options, and hopefully, will make the right choice. Cheers 92.30.6.212 (talk) 16:49, 26 October 2010 (UTC)

A reliable source for information about my mobile phone's software

My Sony Ericsson K850i mobile phone recently failed with a problem described in many places on the internet as the "blue ring of death". My research suggests I need to update the phone's firmware if I am going to try to fix the problem. However, all the information I have comes from various forums and fan-sites and seem mostly concerned with overcoming percieved shortcomings in mobile phones. Some sites also offer links to software tools to help with updating the firmware, but the software is usually home made, of dubious provenance and often lacking in basic usability or any guidance on how it should be used. Replacement firmware can also be downloaded, but once again it seems to be of dubious provenance.

What I'm looking for is a reliable source, perhaps from Sony Ericsson themselves, which details the file system, software and possible solutions, and perhaps provides software tools and firmware. The source of the software/firmware should give me confidence that my PC is less likely to be infected with malware and convince me that my phone is getting some proper updated firmware (rather than some home modded firmware put together by a fanboy in his bedroom).

Particularly important in my case, is to find out how I can recover my list of contacts, which everyone so far has said will be destroyed by the firmware update. Astronaut (talk) 23:22, 25 October 2010 (UTC)

How about the shop you bought the phone at, or your mobile-phone contract provider? They may be able to repair the phone for you. Nimur (talk) 23:34, 25 October 2010 (UTC)

Forgot to mention, the shop where I bought it said they couldn't do that if it was out of warranty. Astronaut (talk) 23:42, 25 October 2010 (UTC)

Here is the page for your phone on the Sony Ericsson website. I believe you are supposed to run a particular type of cable from your PC to the phone; you can then back up your contacts list and upgrade the firmware. I have had a Sony Ericsson phone (different model) and bought the cable for that model over eBay for under US$5.00. Disclaimer: I never updated that phone's firmware; I used the cable to copy files back and forth. Comet Tuttle (talk) 23:40, 25 October 2010 (UTC)

Mobile phone unlocking

As a consequence of the problems outlined in my question above is that I have found lots of websites offering SIM-lock removal services. As far as I can tell, all these sites will sell you a way to unlock your phone, but none will tell you how to unblock your phone for free. Strangely, I've not seen anyware where I can buy software to unlock phones. My local phone unlocking shop seems to be able to do this in just a couple of minutes with one small laptop. So, if I wanted to go into business unlocking mobile phones, where would I get the software from? Astronaut (talk) 23:36, 25 October 2010 (UTC)

Phone_unlocking#Unlocking_technology suggests various methods, such as leaked unlocking codes, rewriting the firmware, and spoofing SIM data. It's possible the unlocking software is custom made by each person doing the unlocking, and not available for download, certainly not for free or these people would be out of business very fast. I don't have a mobile phone so I don't know if that's a helpful answer or not. 82.44.55.25 (talk) 13:37, 26 October 2010 (UTC)