Small speakers that sound like big ones

[tuga]

I really like JL Audio but they’re not the first choice in home audio from a value perspective. However, I don’t think you need to cut the signal to the mains to enjoy a wonderful integration although it is important you don’t overlap frequencies in the same way any crossover would work from one speaker type to another.

JRs get down to what around 50hz? I’d try augmenting the signal with a low pass crossover on the sub at around 60hz, get the volume right and see how you get on. If you can find a real time analyser app on your phone then by playing some pink noise you can visually see what the volume or gain setting should be on the sub.

Before doing all this you’re going to want to get the sub located in a corner of the room, and you’re going to want to notch out whatever prominent room mode you have. Once that’s done you’re 95% of the way there and it’ll sound great.

Does that JL sub have DSP? If not you’ll want it for the room mode that the sub will likely find!

Jusdging from the anechoic response of the JR149s 60Hz may be a tad too high depending on the slope. Can you control the low-pass slope on a sub?

 

[Sibbers]

Jusdging from the anechoic response of the JR149s 60Hz may be a tad too high depending on the slope. Can you control the low-pass slope on a sub?

Depends on the sub I guess, but all the ones I’ve used have allowed at least 6 and 12db slopes, and most have also offered 18 & 24 dB.

There is one way to truly know what will sound best, it’s fun to do and doesn’t take long! My eyes aren’t helping much but that graph looks to me like 60hz with a 12db slope would be a good starting point, maybe even a little higher? I guess it depends on the room, and all the other stuff too.

I can recommend Octave RTA on the iPhone to get a quick sense of what’s going on with pink noise playing. REW is more accurate and free, but you need a calibrated mic and it’s more faff.

 

[RoA]

I'd agree with the Phantom especially on stands. I just couldn't get on with the visuals and the lack of repairability/throw away ethos.
If you don't mind that I really have never heard anything as small sound so big.

The Phantoms are apparently repairable but I can't say for certain. I owned the Formation Duo's until very recently. Very small speakers with a huge (!) Sound.

 

[mercalia]

The size of the room is important? I have Monitor Audio R852MD, EPos M5i & M12i and part from tonal issues they have the same "size" sound. They differ in their bass response as the M.A is a closed box design and the M12i has the resistor in it so the treble aint so shrill compared to the M5i. Clearly you need a big speaker for a big room to move alot of air easily

 

[ToTo Man]

My eyes aren’t helping much but that graph looks to me like 60hz with a 12db slope would be a good starting point, maybe even a little higher?

Unless @mandryka has a room lonnger than four and a half metres and/or has his JR149s and listening seat well away from boundaries then I suspect that 60Hz 12dB/oct will result in significant overlap, as JR149s in my 4.2m x 3.8m x 3.25m roomm still catch a fair chunk of my 43Hz mode even when my seat is 1m from the wall:

If you don't want overlap then integrating a sub will likely be difficult unless the JRs are high-passed, unless perhaps you just want to extend the LF below where the room's length mode drops off, in which case I'd suggest starting with a 24dB slope and very low XO frequency on the sub/s. However, this won't bring any additional power handling to the JRs as you aren't high-passing them.

I haven't tried it as I don't have the facility to high-pass my speakers, but based on the JR149's response in my own room, I'd probably high-pass and cross them over to my subs at 80Hz to achieve more room-filling impact.

Alternatively, if you're able to listen to your JR149s in more of a nearfield equilateral triangle of between 1m and 1.5m, you may find that you gain a lot of the air-shifting impact you are currently missing at your farfield listening distance and avoid the need for sub/s.

 

[Gervais Cote]

Maybe the title of this thread should be changed to "do small speakers need a sub ?"

 

[RJohan]

My own recent experiments with sub's (two of them) concurs what To to man has written.

I can only add that with two sub's, a good starting point when it comes to where to place them is: Both subs along the wall behind the main speakers, one of them near to a corner, the other one something like 1/4 or 1/3 along the wall, counted from the other corner.

 

[Sibbers]

Maybe it would overlap, in which case bring the crossover down. It depends on so many things and the theory gets you a lot of the way, but trying it all out can be surprising and is necessary to get it all set right. I have DSP on my whole signal, so it's a little different to just adding a sub, setting a low pass and getting the gain right but my mains go much lower than JRs and I don't high pass them. I've added subs to other folks unsophisticated systems to add in what their mains can't do, its taken a few minutes to get right and it's sounded wonderful. I'm saying this to assure anyone reading that it can be done and can sound great (much better than mains alone) and not to disagree with what anyone else has or is saying

REW has a cool feature that allows you to simulate placement in your room which is pretty useful, certainly worth a look. Best for subs I think, but you can also use them for mains and see how everything interacts with each other too.