15 ms latency problem

[Nogi57]

Hi,

I have a latency problem, maybe you could help?

Here's below some specs and the JamKazam report.

Windows 7(64 bits)
Proc.: Intel® Core™ i5 CPU 760 @ 2.80GHz
RAM : 4,00 Go
Uplink bandwitch : 10Mbps (JK required 1Mbps)

JamKazam Audio Configuration Review Report :
1.Poor Audio Latency: Audio input/output latency is 15 ms. Tuning or changing your audio device could reduce latency less than 5 ms.
2.Excellent Audio Frame size: Your audio frame size is 2.5 ms.
3.Excellent Audio Driver: ASIO.
4.Excellent Input Sample Rate: Your audio input-output sample rate is 48000 (or multiple).
5.Excellent: Wired Network(RG45 15ft Ethernet cable).
6.Excellent Packet Rate: Your default packet rate is 400 pkt/s.

External Sound Card : Tascam US-600;
Session Audio Inputs(Live Tracks) : US-600 - ASIO;
Session Audio Outputs(Requires 2 Ports) : US-600 analog L/R - ASIO(same as Inputs).

I am a drummer using an electonic drumkit, with 1 microphone(XLR - ch 3) via an 4 channels analog mixer :
Electronic drumkit module to analog mixer via 2-TRS(ch. 1-2, panned L/R);
Analog mixer to my external sound card via 2 others TRS;
External sound card to my computer via a 6ft USB 2.0 cable.

So what may cause the 15 ms latency? I read that ASIO bypass the internal sound card, so why my external sound card is the problem? Even if the ASIO driver in/from it is excellent(as JK report saying)?

Thank you.

Nogi57