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
Best Sellers Rank	#5,250 in Electronics ( See Top 100 in Electronics ) #16 in Audio Component Amplifiers
Brand	Fosi Audio
Built-In Media	32V/5A Power Supply x1, Bluetooth Antenna x1, Fosi Audio BT30D PRO Subwoofer Amplifier x1, User Manual x1
Customer Reviews	4.5 out of 5 stars 1,777 Reviews
Item Type Name	Bluetooth Amplifier
Item Weight	1.5 Pounds
Manufacturer	Fosi Audio
Mfr Part Number	BT30D Pro
Model Number	BT30D PRO
Unit Count	1.0 Count
Warranty Description	24 Month Manufacturer

Bluetooth Subwoofer Amplifier 2.1, BT30D Pro Subwoofer Amp with TPA3255 Chips 165W x2+350W & Bass Treble Control, 2.1 Channel Sub Amplifier for Desktop/Outdoor/Bookshelf Speakers

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