I've trained a Sphinx2 acoustic model using 14 hours of speech data, and I've been testing it with a set of utterances that were held out of the training set. Results are OK -- good.
Then I noticed that the script I'd been using to run Sphinx (which was adapted from scripts/sphinx-train) had -agcmax TRUE, whereas I'd run the SphinxTrain scripts with the default CFG_AGC = 'none'. Oops! I've noted in several places in the Sphinx docs from the CMU website that it's stressed that the AGC parameter of the decoder must match that of the acoustic model. So I just made a new trial in which I changed only -agcmax to FALSE, and I was surprised to find that the matchfn file is IDENTICAL to before -- even the reported scores are the same. I did verify from the log files that AGC_MAX was running in the first case, with no AGC in the second.
So what could be happening to cause IDENTICAL results? Was the AGC-MAX actually doing nothing in the first case? Here are the sphinx parameters:
I've trained a Sphinx2 acoustic model using 14 hours of speech data, and I've been testing it with a set of utterances that were held out of the training set. Results are OK -- good.
Then I noticed that the script I'd been using to run Sphinx (which was adapted from scripts/sphinx-train) had -agcmax TRUE, whereas I'd run the SphinxTrain scripts with the default CFG_AGC = 'none'. Oops! I've noted in several places in the Sphinx docs from the CMU website that it's stressed that the AGC parameter of the decoder must match that of the acoustic model. So I just made a new trial in which I changed only -agcmax to FALSE, and I was surprised to find that the matchfn file is IDENTICAL to before -- even the reported scores are the same. I did verify from the log files that AGC_MAX was running in the first case, with no AGC in the second.
So what could be happening to cause IDENTICAL results? Was the AGC-MAX actually doing nothing in the first case? Here are the sphinx parameters:
sphinx2-continuous -verbose 9 \ -adcin FALSE \ -cepext feat \ -ctlfn ${CTLFILE} \ -ctloffset 0 -ctlcount 100000000 \ -datadir ${FEATS} \ -agcmax TRUE \ -langwt 6.5 \ -fwdflatlw 8.5 \ -rescorelw 9.5 \ -ugwt 0.5 \ -fillpen 1e-10 \ -silpen 0.005 \ -inspen 0.65 \ -top 1 \ -topsenfrm 3 \ -topsenthresh -70000 \ -beam 2e-06 \ -npbeam 2e-06 \ -lpbeam 2e-05 \ -lponlybeam 0.0005 \ -nwbeam 0.0005 \ -fwdflat FALSE \ -fwdflatbeam 1e-08 \ -fwdflatnwbeam 0.0003 \ -bestpath FALSE \ -kbdumpdir ${LMDIR} \ -lmfn ${LMDIR}/7568.lm \ -dictfn $youth/etc/youth.dic \ -noisedict $youth/etc/youth.filler \ -phnfn ${HMM}/phone -mapfn ${HMM}/map -hmmdir ${HMM} -hmmdirlist ${HMM} \ -8bsen TRUE -sendumpfn ${HMM}/sendump \ -cbdir ${HMM} \ -matchfn $youth/test/test.match_7000 \ -logfn $youth/test/test.log