Question 1

What is the subwoofer frequency crossed at?

Accepted Answer

According to the Fosi site, the 'sub freq' knob does exactly what you would expect, acts as a variable crossover point control. ""...adjustable 40-300Hz cutoff frequency for subwoofer...  It doesn't say what the slope of the cutoff is.

Question 2

Are they screw fasteners for the speaker wires?

Accepted Answer

The unit has a set of combination binding pot/RCA connections. So it will accept bare wires or RCA connectors for your speakers.

Question 3

has any one used this with a non powered sub, and did it sound OK ?

Accepted Answer

William, I have this Fosi amp for a small patio sound system. I do have a sub speaker but it is powered and not passive. I am 100% satisfied with the sound of my system. The Bluetooth works great as well as the aux input. This however does not answer your question but I may give you something to consider. According to Fosi specs, the rated output is 50 watts + 50 watts + 100 watts. I deduce that to mean 50 watts for each left & right speaker and 100 watts for sub speaker. That should be a sufficient 2 to 1 ratio for output division. Fosi also states that the output can be increased with an option 8 amp power supply, but they don’t state exactly how much the output increases. Whether or not a passive sub speaker would “sound ok” has many other variables, ie: size of speaker, sensitivity of speaker, speaker material, type of enclosure that houses speaker, if the enclosure is ported and if the port is tuned properly, if speaker is front firing or down firing, acoustical environment, etc, etc. It is possible a passive mode that the sub speaker may not “sound” satisfactory but may not be the fault of the Fosi amp. I hope this was helpful.

Question 4

I see in some reviews that there should be a bluetooth/rca switch on the back , but no switch exists on mine. how do i switch to bt and pair it?

Accepted Answer

For the BT30D theres a power switch on the front.  When you turn it on it activates the Bluetooth, but uses the RCA jacks until you actually pair a device via Bluetooth.  Just unpair the Bluetooth if you want to use a turntable or DAC.

ASIN	B09YNBHR73
Audio Output Mode	ステレオ
Audio Output Type	bluetooth
Brand	Fosi Audio
Compatible Devices	Speaker
Connectivity Technology	Bluetooth
Connector Type	RCA
Customer Reviews	4.4 4.4 out of 5 stars (1,614)
Item Weight	680 g
Model Number	BT30D PRO
Number of Channels	3
Other Special Features of the Product	Built-In Bluetooth, RCA, Subwoofer
Output Wattage	165 Watts
Wattage	165 W

Bluetooth Amplifier Power Amplifier 5.0 Stereo Amplifier Audio Amplifier

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