Gainclone Running 2 Speakers; Parallel or Series

Hi all. I have a DIY gainclone purchased years ago from another 'goner. It uses LM3886 chips and has four 8600uF caps for a total of 34,400uF. I am trying to hobble together a system using parts I have on hand. I hooked up the gainclone to a pair of Advent 1 speakers, and felt that they sound bass-boomy and a bit dull. I would like to supplement the Advents with some Gallo Nucleus speakers I have on hand. I believe the Advents are 4 ohms and the Gallos are 8 ohms. Can anyone recommend whether I should wire these in parallel or in series? I can't recall if I've read that gainclones don't like low impedances - if this is the case, I'm guessing in series is better. Can anyone advise? Thanks.
This sounds like a bad idea. Have you checked that the output level of the speakers will be the same at a given power input from the amp? If not, one speaker pair will play louder than the other.

Also, the overall impedance will be below 4 ohms if you put them in parallel. And if you put them in series you'll have over 12 ohms and the output level will suffer.

You could try it but I wouldn't expect very good results. Are you sure the tweeters are working right in the Advents?
I will check the tweeters but the may sound dull due to their positioning - too much upholstered furniture around them. Not sure I can get my GF to raise the speakers above the furniture, and they are positioned in corners.

You're right about the SPL balance b/t the two speakers (e.g. a Gallo sitting on top of an Advent) - although one can only tell by trying it out, right?

I would go series not parallel. I went back and looked at posts online, and some people state that 4 ohms is on the low side for this chip amp. If 8 ohms is good, 12 ohms may not be that far off. Again - regarding output level - seems like it's worth a try. if I'm maxed out and close to clipping, I'll veto the idea. But if there is plenty of headroom....

Thanks Plato.
So wiring in series worked pretty well. The gainclone has no problem powering the combination of the two speakers. The combination is a little on the brighter side, but so much better than the Advents alone, which were really subdued in their positions. This works best for the positioning available.