JBL 305p MkII, choosing/setup of a subwoofer to pair with it, mixed questions etc...

[Marcus Aseth]

Hi guys, I'm new here and hopefully this is the right place (because I'm struggling to get the answers I need x_x)
Below I'll post one or more question regarding my audio setup, but before that a quick overview of my current setup:

Overview of my setup:
This is a small room (maybe 3x4 meters) desktop computer audio setup, currently I have a pair of JBL 305p MkII connected to an Audio Interface U-Phoria UMC22 and the next piece I'll be adding to it is the subwoofer.
The 3 contenders for the position of subwoofer are: JBL LSR 310 S (399€) | YAMAHA HS8S (475€) | SVS SB1000 PRO (600€) - prices are what I can get from my country, Italy.
This setup goal is to have an amazing music listening experience, so hopefully what I'm using (and planning to use) will achieve that.

now for the mixed questions:

Question 1:
on the back plate of my JBL 305p MkII there is an "Input Sensitivity" swith with settings "+4dBu" and "-10dBv"
Right now they are set to "+4dBu" with the Volume knob to 10 (max), and from the audio interface the volume is to 12 o'clock for normal listening and 3 o'clock for music (high volume) - the knob from the interface can reach 5 o'clock max, so is not cranked up ever.
I am using balanced XLR to TRS cables to connect to the U-Phoria UMC22 Audio Interface and the Monitor and "user guide" says: "set the switch to +4 dBu setting when: connecting 3 series mkII speakers to professional equipment with a +4 dBu nominal output level...etc..."
So the question is, does U-Phoria UMC22 has this +4 dBu nominal output level? I think it doesn't...can you guys confirm? And if it doesn't, should I consider buying a new interface? Is the U-Phoria UMC22 messing the sound in any way?

Question 2:
this question is about choosing the correct subwoofer, so I'll post some graphs of the 3 contenders:
JBL LSR 310 S:
Can't find Graph...
YAMAHA HS8S:

SVS SB1000 PRO:

Keeping in mind my goal is an awesome music listening experience, here's the pro and cons I've found with them:
JBL LSR 310 S
PRO:
-It is made to match my JBL 305p mkII so I wouldn't need to stress about things I don't understand for it to sound great, I assume
-Down-firing, means I can rotate it 90° which would improve cable management a lot (no cables touching ground)
-Cheapest
CON:
-Can't find the graph for it
-It is out of stock until September - not sure I can wait

YAMAHA HS8S
PRO:
-Down-firing, means I can rotate it 90° which would improve cable management a lot (no cables touching ground)
-Available right now
CON:
-Smallest woofer of the 3
-Graph shows it starts declining around 30Hz

SVS SB1000 PRO
PRO:
-Sealed, which is supposed to give me tighter and more punchy base? (that's what I think I have understood anyway)
-Graph show starts declining below 30Hz
-Biggest woofer
CON:
-The most expensive
-Should be facing towards me, which given my setup means I'll have cables touching the ground, making it annoying every time I need to clean the room
-Doesn't use balanced XLR/TRS cables, so I don't even know how this connects to what I got, but I assume it makes things harder (maybe worst?)

So, the problem is I don't have any reference real life experience to know how much the fact the yamaha starts declining at around 30Hz will impact my music listening experience, or how superior the SVS SB1000 PRO is, assuming I can even hook it up to all this
So maybe I need some suggestions/opinions from you guys before choosing.
If I had the SVS SB1000 PRO for 6 months and just listened to music, and then switched to the Yamaha, do you think I would notice a difference and be mildly disappointed by it?

Question 3:

This is from the Yamaha manual, explaining the usage of the Low Cut and High Cut knobs, and I still don't quite get it.
Can you explain this to me and more in the specific what would be the actual setting of the two knobs for blending correctly with my JBL 305p MkII?
This is the graph for my JBL (in Blue)

Question 4:
Reading the Yamaha manual I've noticed it mention turning this things in order: First the source (interface, etc...), second the subwoofer, third the monitors - and turning everything off in the reverse order.
I have a power switch with the monitors hooked to it, what would happen if I plug the sub as well there and turn ON/OFF subwoofer and monitor at the same time? Will this damage the equipment over time?

This all the question I have for now, I'll probably have more in the future

 

[lovinthehd]

Just in regard to the output of your Uphoria, it appears to use unbalanced line outs and assume you're using a converter cable rca to xlr or trs? I use an old 2ch preamp with rcas, and a converter cable and use the -10dB setting on my 305s. The +4 setting would be more when you have balanced outputs....

 

[Marcus Aseth]

Just in regard to the output of your Uphoria, it appears to use unbalanced line outs and assume you're using a converter cable rca to xlr or trs? I use an old 2ch preamp with rcas, and a converter cable and use the -10dB setting on my 305s. The +4 setting would be more when you have balanced outputs....

I am using this cable

 

[lovinthehd]

I am using this cable

Maybe I took too quick a glance. Which port on the Uphoria are you using for output?

 

[Marcus Aseth]

Maybe I took too quick a glance. Which port on the Uphoria are you using for output?

you did, otherwise you would know that is not even a question since it only has 1 type of output
Please, no offense, but I would prefer if you refrain from from "helping" me lol

 

[lovinthehd]

you did, otherwise you would know that is not even an option since it only has 1 set of outputs

I saw two sets of rca outputs and some midi ports.....and just went back and realized I clicked on the wrong Behringer unit. Where's that coffee?

 

[Marcus Aseth]

I saw two sets of rca outputs and some midi ports.....and just went back and realized I clicked on the wrong Behringer unit. Where's that coffee?

Ok, no problem if was just a misunderstanding, forget my previous reply.
I had bad experiences in the past getting "helped" by someone who had no idea what they where talking about thus brought me along on a rollercoaster ride which ended in a colossal waste of time xD
If that was not the case there, my apologies

 

[lovinthehd]

Okay now I went thru more of your post (at first it was TLDR ). One advantage of the 310S matching sub is it can provide a high pass for your speakers, i.e. an actual crossover for your speakers in conjunction with the low pass filter it has for the sub itself, altho IIRC its fixed at 80hz but check the manual. The Yamaha also appears to have crossover (low cut/high cut) but with more adjustability

I wouldn't go to an 8inch sub, tho, minimum I'd consider is a 10 (old adage about no replacement for displacement). The bit about turn off/on sequence may be to avoid amp "thump". Annoying but probably not particularly harmful unless at extreme levels perhaps. While the JBL isn't particularly deep-digging either, the SVS would be the best in your grouping for low frequency extension, but I'd rather have the PB1000 (ported version).

While much music doesn't have a lot of content for low bass, that depends what you listen to. I prefer to have the capability myself. YMMV.

How big is your room in terms of volume?

 

[Marcus Aseth]

How big is your room in terms of volume?

38m³ more or less (but ignoring the furniture... with it, I have no idea)

 

[lovinthehd]

Shouldn't be an issue particularly then since that's a relatively small room. Along those lines, don't know if you've seen this article before https://www.audioholics.com/loudspeaker-design/subwoofer-room-size

 

[lovinthehd]

Ok, no problem if was just a misunderstanding, forget my previous reply.
I had bad experiences in the past getting "helped" by someone who had no idea what they where talking about thus brought me along on a rollercoaster ride which ended in a colossal waste of time xD
If that was not the case there, my apologies

Thing was my search had your model up first, but I clicked on a different model that was next to it and my addled brain thought they were both the same even though the model was quite different

 

[Marcus Aseth]

I would actually prefer the SVS, I can probably figure something out for the cable management, my only concern about it is the fact the stuff I got here is studio oriented equipment using balanced XLR to TRS cables and monitors set to +4dBu (as pretty much all google results seem to recommend) so my concern is how it would connect to the rest of the stuff here and if this mismatch would cause problems...

 

[lovinthehd]

Some subs have balanced inputs, like the 310S.....