> ----- Original Message ----- > From: Bill Unruh > Sent: 05/01/14 06:40 AM > To: chris hermansen > Subject: Re: ASUS Xonar Essence STX/low impedance (16-32 ohm) headphones support > > On Wed, 30 Apr 2014, chris hermansen wrote: > > > > Clemens and list, > > > > On Apr 30, 2014 12:07 AM, "Clemens Ladisch" <cladisch@xxxxxxxxxxxxxx> wrote: > > > > > > Bill Unruh wrote: > > > >> On 29/04/14 15:52, Balduin Waldmeister wrote: > > > >>> So my question is whether it's possible to add the low impedance support > > > >>> (16 - 32 ohm) to ALSA for use with the old STX? Currently it stops at > > > >>> the normal gain setting (< 64 ohm). > > > > > > > > That has to do with the capabilities of the amplifier on board the sound card, > > > > not the settings of the card. The amplifier needs to be able to deliver high > > > > current and have a low output impedence-- ie it is a hardware issue. > > > > Not at all sure what the impdence settings on the card would do. > > > > > > The "impedance" setting just lowers the volume. (<300 ? and <64 ? are > > > -6 dB and -18 dB.) I didn't think this was worth implementing in the > > > Linux driver, but people whined until I did. > > > > > > It is certainly possible to add a fourth setting. > > In the advertising bunff from the company, they have graphs with horrendously > unequal frequency response ( a huge bump in the middle of the spectrum) and > they say that the impedance setting boost bass and treble more than mids to > equalize it. Now that could be just marketing having no idea, or it could mean > that the designers designed a horrendous output stage with large capacitive > and inductive loadings so that into low impedances, they took over and > produced very bad frequency response, and those setting stuck in compensatory > bass and treble boosts. But you might also be right that this is all > marketing. Maybe this EQ happens in Win$ driver, depending on impedance settings? > > > > > > > Being charitable, this might not be a HiFi Voodoo stunt by Asus > > > marketing, but an honest attempt at preventing unhealthily loud > > > output levels ... > > Or to prevent distortion since the low impedance may demand too much current > for the drivers at higher amplitudes. Best regards Per Andersson Senior developer Artifex Software artifex@xxxxxxxxxx ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available. Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
