Audio input on laptops with "combo" audio jacks - Page 1
Forum section: electronics / general

author: Peabody
author_rank: Super Contributor
timestamp: June 11, 2019, 05:23:57 pm
content: I'm currently using an 8-year-old Windows 7 computer which has separate microphone and headphone jacks. But I need to get a new Windows 10 computer, and am looking at a Lenovo Thinkpad, which has a single "combo" audio jack. Apparently that's done so it will work with single-plug headsets.I understand the connector is TRRS, CTIA standard, which has stereo headphone output on T and R1, Ground on R2, and Microphone on S. So presumably, one of these adapters would allow the use of a separate microphone, although only a monaural one:https://www.ebay.com/itm/112592360591Not having a combo port to test, I wonder if the mic input in the combo port provides bias voltage that allows the use of electret microphones. My guess is that the mics in headsets are electret, and that the bias voltage is provided (2.5V or so), but would appreciate it if someone who has actually used one of these adapters for electret mic input could confirm that. It would also be helpful to confirm that the Windows 10 (or Lenovo) driver for the combo port has the same microphone "boost" setting that I have on Windows 7, which gives me a choice of 0, 10, 20 or 30db additional gain, and which therefore allows the mic input to be used for either mic or line input.Just to see if it would work, I got one of these cheap USB generic audio adapters:https://www.ebay.com/itm/163066342283It works for electret mic input, including providing bias voltage, but is very noisy. In addition, the Windows 7 generic driver for these devices doesn't provide any mic boost gain options, so even with regular gain set at 100%, it's barely audible, and certainly not useable.So I wonder what kind of USB sound card or interface I would need for Windows 10 for stereo audio input - both line and electret mic. If anyone has used an inexpensive device for that purpose, I'd like to know about it.Thanks for any wisdom on this whole subject.

author: MrMobodies
author_rank: Super Contributor
timestamp: June 11, 2019, 07:37:22 pm
content: I have used a usb Sound blaster Live 5.1 (SB0490) that I got on Ebay and there was still driver support for Windows 10 (when I last checked last year) on their website but that maybe be too big for you to carry around.

author: soldar
author_rank: Super Contributor
timestamp: June 11, 2019, 10:02:54 pm
content: I am sorry I cannot be of help to the OP but I just thought I'd mention that not one of my laptops has had decent audio and most had more or less noise and hum. I wonder if an external USB audio "card" would be an improvement over the internal one.

author: mariush
author_rank: Super Contributor
timestamp: June 11, 2019, 11:32:47 pm
content: There are USB soundcards which are much better than those cheap adapters (often using reference design from datasheets and skimping on capacitors and filtering)Creative Sound Blaster PLAY! 3 24-bit 48KHz USB Interface Sound Cardhttps://www.newegg.com/creative-sound-blaster-play-3/p/N82E16829102100?Item=N82E16829102100Creative Go! 70SB129000000 24-bit 44.10 kHz USB Interface X-Fi Go! Pro Sound Boardhttps://www.newegg.com/creative-go-70sb129000000/p/N82E16829102036?Item=N82E16829102036

author: 3db
author_rank: Frequent Contributor
timestamp: June 12, 2019, 12:55:17 am
content: You could check out some cheap mixers with built in usb audio interface.There are also a huge range of Audio interfaces used with music production software.3db.

author: rdl
author_rank: Super Contributor
timestamp: June 12, 2019, 11:31:49 pm
content: I have an Audioquest Dragonfly. I bought it used on ebay a few years back for $45. I don't think I have never heard sound this good from a computer before, and I've had some very expensive soundcards in the past. I think any decent quality USB DAC is going to provide much higher quality sound than any built in solution. I'm pretty sure it's due in large part to just being outside the computer away from any noise.

author: wraper
author_rank: Unknown
timestamp: June 12, 2019, 11:47:01 pm
content: I use old Nokia AD-83 headset with self made USB-A -> micro usb adapter (there is off the shelve stuff these days) for 10 years. Best computer microphone ever. Can talk via Skype 5 meters away without any issue. Even media buttons do work, except call button.

author: Richard Crowley
author_rank: Super Contributor
timestamp: June 13, 2019, 12:06:55 am
content: It is quite safe to assume that both CTIA and OMTP standards apply "bias" voltage to the microphone input. Mass-market communication accessories like cellphone headsets, etc. have been essentially 100% electret for decades.Of course the TRRS audio connectors feature only monaural input, and the mic preamps for those ports are "communication grade" at best. If you need decent quality audio input (or output for that matter), then using a USB-based audio interface is required. Even those little $3 "thumb-drive" size gadgets are better quality than most anything built into any computer.

author: tooki
author_rank: Super Contributor
timestamp: June 14, 2019, 02:45:01 pm
content: Quote from: Peabody on June 11, 2019, 05:23:57 pmMy MacBook Air also has a CTIA combo jack, and I’ve used an adapter like that to use a high quality headset, and it works well. They have to provide bias voltage, because otherwise the microphone couldn’t work. (Mobile headsets do not contain their own power sources.)Quote from: Richard Crowley on June 13, 2019, 12:06:55 amElectret or MEMS, nowadays. MEMS microphones are probably dominant these days, due to their small size, which works better in the inline mike/remotes in mobile headsets.Quote from: Richard Crowley on June 13, 2019, 12:06:55 amI guess I’m spoiled with the fairly good audio that Apple builds into its devices, because all the thumb drive style audio interfaces I’ve used have been the same quality at best, but mostly noticeably worse, in some cases dramatically worse.But honestly, while no onboard audio is studio grade, it’s certainly not “communication grade”.

author: Peabody
author_rank: Super Contributor
timestamp: June 14, 2019, 10:45:11 pm
content: Thanks for the comments and suggestions. I would like to avoid interfaces with XLR and 1/4" connectors because everything I have would just use 3.5mm. It appears there are a number of thumbdrive interfaces that cost a bit more than the $3 one I tried, but also work a lot better. The things that might be difficult to find at low cost are line input and stereo input. But I might be able to get by without those, at least in the beginning.

author: magic
author_rank: Super Contributor
timestamp: June 15, 2019, 12:03:03 pm
content: Given that integrated soundcards always worked with electret mics out of the box, I would be surprised if they suddenly screwed things up in latest gen laptops. That would be plenty of pissed-off users.