  In recent studies, it has shown that speaker patterns can be learned from
very short speech segments (e.g., 0.3 seconds) by a carefully designed
convolutional & time-delay deep neural network (CT-DNN) model. By enforcing the
model to discriminate the speakers in the training data, frame-level speaker
features can be derived from the last hidden layer. In spite of its good
performance, a potential problem of the present model is that it involves a
parametric classifier, i.e., the last affine layer, which may consume some
discriminative knowledge, thus leading to `information leak' for the feature
learning. This paper presents a full-info training approach that discards the
parametric classifier and enforces all the discriminative knowledge learned by
the feature net. Our experiments on the Fisher database demonstrate that this
new training scheme can produce more coherent features, leading to consistent
and notable performance improvement on the speaker verification task.
