hm.. it seems that the previous mail wasn't sent.... here again:
hello martin peach
i tested your external a bit more deep on the 'good' soundcard, where i can exclude aliasing introduced by the soundcard. it turned out, that a bit of aliasing is audible in the range above 5000Hz. i think this is not tooo bad, maybe for 'pure'ists. but i had serious troubles, when loading some patches, that contain [sqosc~]. it can happen, that after loading the patch, pd is sending constantly a dc to my soundcard. even when i close pd, the dc stays on these channels, where pd was connected before over jack. to get rid of the dc, i must restart jackd again. because of that, i assume it is related to jackd (is it possible to crash jackd from pd?). i attached a test-patch. when loading that patch, jackd (and pd) get unusable for sure.
my system: ubuntu dapper i386 pd-0.40.2 jackd 0.100.0
when i create a patch from scratch with [sqosc~], i have no troubles. i get the dc also, when i open the help-patch of [sqosc~].
roman
___________________________________________________________ Der frühe Vogel fängt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
and forgot the attachment this time..... no day without that.....
On Sun, 2007-03-25 at 20:42 +0200, Roman Haefeli wrote:
hm.. it seems that the previous mail wasn't sent.... here again:
hello martin peach
i tested your external a bit more deep on the 'good' soundcard, where i can exclude aliasing introduced by the soundcard. it turned out, that a bit of aliasing is audible in the range above 5000Hz. i think this is not tooo bad, maybe for 'pure'ists. but i had serious troubles, when loading some patches, that contain [sqosc~]. it can happen, that after loading the patch, pd is sending constantly a dc to my soundcard. even when i close pd, the dc stays on these channels, where pd was connected before over jack. to get rid of the dc, i must restart jackd again. because of that, i assume it is related to jackd (is it possible to crash jackd from pd?). i attached a test-patch. when loading that patch, jackd (and pd) get unusable for sure.
my system: ubuntu dapper i386 pd-0.40.2 jackd 0.100.0
when i create a patch from scratch with [sqosc~], i have no troubles. i get the dc also, when i open the help-patch of [sqosc~].
roman
___________________________________________________________ Der frhe Vogel fngt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Roman Haefeli wrote:
i tested your external a bit more deep on the 'good' soundcard, where i can exclude aliasing introduced by the soundcard. it turned out, that a bit of aliasing is audible in the range above 5000Hz. i think this is not tooo bad, maybe for 'pure'ists.
Do you get the aliasing also with [osc~]?
Martin
On Sun, 2007-03-25 at 21:46 -0400, Martin Peach wrote:
Roman Haefeli wrote:
i tested your external a bit more deep on the 'good' soundcard, where i can exclude aliasing introduced by the soundcard. it turned out, that a bit of aliasing is audible in the range above 5000Hz. i think this is not tooo bad, maybe for 'pure'ists.
Do you get the aliasing also with [osc~]?
no, not when i test on the 'good' card. when playing [osc~] or the bandlimited oscillators i posted in previous mails, there is absolutely no aliasing hearable (on the rme-card). i tested all with an sr=44100Hz.
there is somethings else, i forgoto mention: when playing [sqosc~] with low frequencies (<100Hz), it sounds a bit dull compared to a raw square with the same amplitude and the same frequency. does [sqosc~] not play the full spectrum in the low area?
roman
___________________________________________________________ Der frühe Vogel fängt den Wurm. Hier gelangen Sie zum neuen Yahoo! Mail: http://mail.yahoo.de
Roman Haefeli wrote:
there is somethings else, i forgoto mention: when playing [sqosc~] with low frequencies (<100Hz), it sounds a bit dull compared to a raw square with the same amplitude and the same frequency. does [sqosc~] not play the full spectrum in the low area?
There are two things: first the sqosc~ wave is not as loud as osc~ or a raw square: you need to multiply it by 1.333 to get -1 to +1. Second, the wave is always bandlimited. If you think about it, a raw square wave has components at the highest frequency at the transitions, so you always get aliasing effects, even at low frequencies. In effect the transition usually happens at the wrong time at low frequencies, so there is a kind of jitter introduced, which can be noticeable if the wave is near a subharmonic of the sampling frequency. [sqosc~] is slew-rate limited so the transitions always happen at the right time, but they are smeared out a bit.
Martin
-
Martin Peach -
Roman Haefeli