For the low to moderate volume listening your apartment location dictates, that 40 watt JoLida will be sufficient with medium (honest 87 dB) efficiency speakers. I was a Jolida dealer for many years and imo you made an excellent first amplifier purchase for a newcomer to the scene.
There is an inevitable tradeoff relationship between small box size, high efficiency, and deep bass extension. Basically you can have any two of the three but not all three. So assuming there is a maximum box size you can live with, you'll be trading off efficiency vs bass extension within that box size limit, but I don't think especially high efficiency is needed for low to moderate listening levels.
One factor which is seldom obvious from the published specs is the shape of the impedance curve. Tube amps generally sound better with a speaker that has a fairly smooth impedance curve. Impedance peaks in the bass region are usually okay, but major dips and/or major peaks elsewhere in the curve can work against compatibility with an amp like your Jolida. I say this as a speaker manufacturer who designs with tube amp compatibility in mind.
I think it's great that you will be visiting several dealers to audition their speakers. Imo you should call them in advance and tell them what you've told us, and they can each make their best recommendations from their lineup and be prepared to put their best foot forward for your particular needs. You might approach your quest as a two-stage process: First round, listening in order to create a short-list of speakers that are the best candidates. Second round, bring your amp and listen more extensively to the short-list speakers to make your final selection.
I suggest trying speakers at a wide range of volume levels, as some speakers that sound great at medium levels tend to sound lifeless at low levels. Generally speaking high efficiency speakers tend to do better than low efficiency speakers in this regard, but there are enough exceptions to keep this from being a reliable rule.
One suggestion should help with selecting a speaker from your short list that is non-fatiguing over the long term: Turn the volume level up a bit louder than normal and walk out of the room, listening through the open doorway but with no line-of-sight to the speakers. From out there, all you can possibly hear is the reverberant field. Is there a reasonable illusion of live music happening in the room, or is it painfully obvious that you're listening to speakers? I believe that there is a good correlation between speakers that get the reverberant field right and long-term listening enjoyment, and this test, call the L.I.A.R test (Listening In Another Room), throws a spotlight on that.
You might also try the different output transformer taps, if your amp has them. Just because it's an "8 ohm" speaker doesn't mean you can't try the 4-ohm taps. You will probably lose some maximum output power with a "mis-match", but if you gain in sound quality and don't need the extra power, who cares? I built a pair of 8-ohm speakers for my parents, and they sounded better on the 4-ohm taps of their Jolida 302b.
If you'd like a crash course in the technical details that make one speaker better suited than another for tube amps I can do that too, but otherwise I'd say trust your dealers to make the best recommendations from their respective lineups.
The Speaker Quest is one of the most enjoyable ventures we audiophiles embark on. Take the scenic route instead of the fast lane and enjoy the journey!
Duke
dealer/manufacturer
There is an inevitable tradeoff relationship between small box size, high efficiency, and deep bass extension. Basically you can have any two of the three but not all three. So assuming there is a maximum box size you can live with, you'll be trading off efficiency vs bass extension within that box size limit, but I don't think especially high efficiency is needed for low to moderate listening levels.
One factor which is seldom obvious from the published specs is the shape of the impedance curve. Tube amps generally sound better with a speaker that has a fairly smooth impedance curve. Impedance peaks in the bass region are usually okay, but major dips and/or major peaks elsewhere in the curve can work against compatibility with an amp like your Jolida. I say this as a speaker manufacturer who designs with tube amp compatibility in mind.
I think it's great that you will be visiting several dealers to audition their speakers. Imo you should call them in advance and tell them what you've told us, and they can each make their best recommendations from their lineup and be prepared to put their best foot forward for your particular needs. You might approach your quest as a two-stage process: First round, listening in order to create a short-list of speakers that are the best candidates. Second round, bring your amp and listen more extensively to the short-list speakers to make your final selection.
I suggest trying speakers at a wide range of volume levels, as some speakers that sound great at medium levels tend to sound lifeless at low levels. Generally speaking high efficiency speakers tend to do better than low efficiency speakers in this regard, but there are enough exceptions to keep this from being a reliable rule.
One suggestion should help with selecting a speaker from your short list that is non-fatiguing over the long term: Turn the volume level up a bit louder than normal and walk out of the room, listening through the open doorway but with no line-of-sight to the speakers. From out there, all you can possibly hear is the reverberant field. Is there a reasonable illusion of live music happening in the room, or is it painfully obvious that you're listening to speakers? I believe that there is a good correlation between speakers that get the reverberant field right and long-term listening enjoyment, and this test, call the L.I.A.R test (Listening In Another Room), throws a spotlight on that.
You might also try the different output transformer taps, if your amp has them. Just because it's an "8 ohm" speaker doesn't mean you can't try the 4-ohm taps. You will probably lose some maximum output power with a "mis-match", but if you gain in sound quality and don't need the extra power, who cares? I built a pair of 8-ohm speakers for my parents, and they sounded better on the 4-ohm taps of their Jolida 302b.
If you'd like a crash course in the technical details that make one speaker better suited than another for tube amps I can do that too, but otherwise I'd say trust your dealers to make the best recommendations from their respective lineups.
The Speaker Quest is one of the most enjoyable ventures we audiophiles embark on. Take the scenic route instead of the fast lane and enjoy the journey!
Duke
dealer/manufacturer