Best LSR6332 & LSR6312 combo?

[sebackman]

Hi,

I was originally thinking of building a set of 4367 after selling the M2's due to size limitations. I then stumbled on some passive LSR6332 monitors which are smaller in size and I really like the very neutral sound in the room I will be using them. So, the 4367 gear will be passed on for someone else to have some building fun.

I know the 6332's don't really need subs but I do happen to have a pair of LSR6312 active subs not being used so it would be ashamed to not pair them with the 6332's.

What would be the best combo for them? I plan to place them on top of each other (pillar) and the question is how to blend them?

There are a number of alternatives and all input is much welcome.

Use the 6312 built in active filters to feed the power amp for the 6332’s and using the woofer in the 6332 above 80Hz as per the 6312 filters?

Let both woofers go “full range” with the 6312 falling off at 80Hz with its built-in filters and no external LP filter on the 6332. Ie feeding both the active 6312 sub and the amps for the 6332's the same signal?

Use external active XO/DSP feeding the 6312 and 6332 adjusted signals and if so what would be the best combination. I do have a few BSS DSP’s laying around and could easily incorporate one of them.

I often find that a mono signal for the subs works better as there is limited directionality below 60-80Hz anyway. Maybe mono signal to the 6312’s below 60Hz bypassing the built-in active filters and full range to the 6332’s?

I saw an old picture of a Harman listening room with 6332’s and they had some subs in the corners but I could not see what model and have no idea how they were connected.

Only for two channel music use.

What say you?

Kind regards
//Rob

[Mr. Widget]

As a general rule of thumb the best way to deploy subwoofers is to use four and place them at the midpoints of the four walls of a rectilinear listening room. Using the four corners is an alternative, which will give you more bass output but is usually slightly less linear.

Of course this is only a rule of thumb. Experimentation with careful listening and measurements is always a good idea prior to your final decision on location. If you don’t have four subs, additional experimentation is a good idea.


Widget

[Robh3606]

Hello

I thought the LSR6312 did the bass management. They have LCR inputs and outputs so I thought the LCR outputs were high passed and the bass was summed. You can also daisy chain the subs as needed. I would try this first.

Rob

[SaturationPt]

I used mine running preamp-out through the balanced inputs/outputs on the LSR6312Ps to the amplifier. This gives you a high-pass and also allows you to use the JBL RMC system, and is less complicated than trying to EQ the summing of the bass that will occur below ~80Hz from the LSR6332s, it is how JBL designed them to work.

I have no complaints on how they worked together.

You can use the RMC without the calibration kit, it's just more trial-and-error to get it flat.

I liked how they sounded together, but wanted deeper bass (LSRs are now gone except the LSR6328P for monitoring).

[sebackman]

Thank you for good input.

I did check my subs and they are LSR12P not LSR6312SP. They have been idle a while, sorry

Mr. Widget
4 subs mid-wall is of course a better solution. This room is pretty decent and I only have two subs. They are not easy to find second hand at reasonable money over here. I could of course place them mid wall front and rear or on the sides. With 4 subs I guess it would make sense to use the woofers in the 6332 as mid-bass only (using the 6312 crossovers or external ones). But with only two?

Robh3606
I'm not really after the "bass management" at this point and the LSR12P does not have that feature unfortunately. It's more finding the best integration, dual LF woofers on each side (LSR12P+6332) or only subs (LSR12P)? Its only for 2 channel listening. LSR12 does not have the ability to daisy chain the same way the 6312 does.
Feeding the 6312 a L+R stereo signal, forward the output to the 62332 amp and using the daisy chain function with two 6312 subs (ie "Summed Out" ) would insert a HP on the 6332 output's and hence only feed mono LF to the two 6312's and a HP signal (>80Hz) to the 6332's (ie only 6312 as LF). If the internal LCR HP in the 6312 is bypassed ("LCR Bypass") so will the LP be, requiring and external filter to feed the 6312 via "Direct-Sub in". Hence no way to use the woofer in the 6312 AND the woofer in the 6332 for LF in such setup.

SaturationPt
Not sure if you used 6332's or 6328's with the 6312's? If it would be 6328 it would make sense to only use 6312 as LF with the larger woofer. It sounds like you have had both? Please elaborate on setup and findings. I can't find any info from JBL covering use of LSR12/LSR6312 in combination with LSR32/LSR6332.

Since the woofer in the 6332 and the LSR12/6312 are similar maybe they can share the burden below 80Hz? 6332 seems to have an cabinet F0 of 33Hz and the LSR12P 28Hz. I don't know why there is a difference as the cabinets are the same size and the woofers are very similar.

I think member Valentin had some similar setup before the M2's.

Thoughts?

Kind regards
//Rob

[Ian Mackenzie]

Hi Rob,

Try a pm to Val.

Having a look are your sub spec sheet l would keep it simple and feed the 6332 direct from your pre out to your power amp and use the subs via the inbuilt crossover to back fill the 6332 existing bass output.

Your 6332 locations x y x relative to the floor, side and front wall surfaces will dictate the 6332 output below 100 hertz. Your subjective imaging will take precedence over the main enclosure locations x, y relative to your listening location. So l would set up the 6332 first for the imaging, then bring up the subs and subjectively adjust. This will ideally provide a natural LF contour to balance the main 6332 enclosures and provide “that” sound your mostly aspire to. Getting the 6332 well off the floor will markedly improve your mid bass / mid definition.

I room response filter with a modest Q and 1.5 dB cut centred @ 290 hertz may further improve clarity as many room emphasis this region.
(Ref DD67000 project system Triamped)

I hope this is useful to you.

https://jblpro.com/en/site_elements/lsr12p-information

[SaturationPt]

<<snip>>SaturationPt
Not sure if you used 6332's or 6328's with the 6312's? If it would be 6328 it would make sense to only use 6312 as LF with the larger woofer. It sounds like you have had both? Please elaborate on setup and findings. I can't find any info from JBL covering use of LSR12/LSR6312 in combination with LSR32/LSR6332.

Since the woofer in the 6332 and the LSR12/6312 are similar maybe they can share the burden below 80Hz? 6332 seems to have an cabinet F0 of 33Hz and the LSR12P 28Hz. I don't know why there is a difference as the cabinets are the same size and the woofers are very similar.//Rob

Both. We purchased the 6328/6312 combo first, then the 6332. The 6328s have since been used without a sub hower as they're set up as nearfield monitors mostly for a keyboard that doesn't benefit from the lower octave.

The 6312s don't go (much) lower than the 6328s, and needed a subwoofer also and I felt that the 6312 compliment was a good match, with the mains high-passed. I didn't realize that the LSR6312P and LS12P are so different, thought that the difference was mainly cosmetic (like the LSR32 with the carbon-fiber baffle and the later LSR6332 with painted baffle), apparently it is more significant and doesn't have the XLR in/out and RMC? You're not missing much with the high-pass, as it is a fixed 80Hz anyway, you cannot configure the cutoff on these subwoofers for the high-pass.

I'm a strong proponent of NOT compounding the sub-bass between the woofers and subwoofers. The woofers do well what they do, high-pass on the mains decreases some of the load on the main amplifier, reduces doppler distortion, and just IMO makes the entire setup easier and cleaner. It might be easier at this point to use a DSP or electronic crossover to simply high-pass the mains low-pass the subs. Better still (IMO) is using the DSP and calibrated mic (many are happy with an inexpensive minidsp) so that you can tune out all of the bumps and holes in your room response while you're in there, and just let those subs do what they do best.

Finally, one of the things that I found with the LSR6312Ps is that they don't really go that low, compared to the LSR6332s. What I found is that it clears up the bass, midbass, leaves more reserve power in the main amplifier, and also delivers a seamless handoff of those frequencies. So not the absolute bass one might want for HT, but for music I felt that they are excellent.

Best of luck in getting them tuned in, try a few things and I'll bet that there are several arrangements that will work. In the end this setup is one of the first 2.1 setups I've run for music where people would be surprised when they are told that there are subwoofers running, and I'd switch them off to convince them. Previously I felt that subwoofers were really more for HT.

[Ian Mackenzie]

Hi Jeff,

My own view is that the issue is how does the main woofer/ enclosure work in this particular setting of x, y, z location?

Playing familiar program material will provide the answer.

Typically a 12 inch monitor is going to have a knee around 45- 50 hertz in an optimal location relative to the room boundaries. See attachments below. That being not hump on the 100 hertz region or peak in the 50 hertz region. The controlling variable is the optimal location for imaging.
This is typically an equilateral triangle defined by the distance between the tweeters and the listening position.

The sub F3 34 hertz incidentally is tuned lower than the 6332 F3 54 with some electrical EQ boost. The sub enclosure volume appears to be identical to the 6332. The sub is possibly a quasi 5th order alignment.



So, assuming Rob had them set up in that location the solution is augmentation of the bass in the region of the main enclosure F3 snd half octave below. This is the role of the subs. Not to replace the role of the 6332 woofers but to supplement the output of the 6332 woofers.

A 12inch woofer is not a 15 inch woofer and to
suggest using only one woofer below 50 hertz will give rise to output limiting and increased distortion. It’s simple physics.

Doubling the cone area equates to 1/4 the cone excursion with a consequent lowering of 2nd thd.

https://jblpro.com/en/site_elements/lsr6332-spec-sheet

[sebackman]

Thank you for the input. Still not clear on how to get this working.

My aim is, exactly as Ian points out, to use both (all 4) woofer to increase output capability while keeping distortion low. Best would be to have the sub's located elsewhere in the room as Mr. Widget pointed out but that is a bit difficult in this specific room.

I have set up the LSR6332 monitors on top of LSR12P below in a different room. They are a about 3 feet out from both the back and side walls. Very limited 6332 bass in this position so maybe the best would be to run the subs as woofers and the monitors crossed a 80Hz. May work better in the other room where they will get closer to both walls.

Now I feed the sub's direct from the preamp in parallel to the power amp for the 6332's, so both are fed full signal albeit the sub's does internally filter @80Hz.

Levels are tricky as the sub is really made to be a mono sub to a pair of satellites receiving both channels, so only feeding one channel lowers the output compared to the amp feeding the 6332's. Maybe I can feed both channels to both subs?

Not really happy with the sound yet. Maybe the power amp I'm using is not up to the task as the 6332's are close to the 2ohm territory around 100Hz and the amp is not spec for 2ohms. Do these need a very powerful amp to work? The one I use is an ordinary decent quality power amp with 2x90W (RMS) @ 8 ohms and 150W @ 4 ohms.

I will try to play around a little more including swap in a bigger amp (Crown) to see what happens. I will also test as suggested to run the 6332's trough the LSR12 filter @80Hz. The last option would be to put a BSS DSP in front of them to do all XO and time alignment, but I would like to avoid that if not needed.

Further input much appreciated.

//Rob

[Ian Mackenzie]

Hi Rob,

I think trying a few configurations is a great idea. Low frequencies are unpredictable.

You may also venture to looking at finer adjustments if the subs have any room EQ adjustments.
Alternatively if you have a home theatre receiver plug that can be temporarily used as a source try run it’s room EQ processor and see what the EQ does?

I have used a Nad C658 preamp streamer with Dirac and that cleaned up the bass in our family room set up. I think Minidsp sell outboard Dirac enable hardware that may possibly interest you. The other option is a Dayton plate amp with EQ in the DSP. Some Crown amps also have inbuilt DSP EQ.

[sebackman]

Thank you for input. Thought I would give some update here.

I ended up changing the gain on the discrete input of the LSR12's. The "Direct" input was +4dbu for 96db / 1m which is about 15db lower than the LSR6332 on a 26db gain Crown amp. I increased the gain about +13db on the input and took the rest on the amp attenuator (CTS1200). Just changing a resistor in the input card.

So far playing nicely and transparent but very position sensitive for good bass. I think I need to get a BSS DSP connected so I can play with delays and phase between the LSR12's and the LSR6332's. I have a BLU50 originally designated for the DIY 4367 that I now can use as the kits are sold.

I have not decided if I want to disconnect the internal analog electronic filters in the sub and run all XO externally with the DSP. LSR12 amps is pretty straight forward so that can be done.

The 12" woofers in the LSR12/6312 are only 2 ohms so they will need a very current capable amp to skip the internal amps so I'm less sure over that. I have some 2 and 4-channel Crown CTS amps that probably would be fine with 2 ohms.

Also need to finalize the room treatment. Currently some bass traps in the corners and I also have some diffusors going on the walls any day now....

Anyway that is were I am today.


Kind regards
//Rob