Polk LSiM703 with a sub in moderate sized room

aboroth00

You shouldn't have to measure each speaker individually because you're mostly concerned with the summed response in-room. You'll probably just PEQ the summed response anyhow and not individual speakers. Post measurements if you can and we can see what you're dealing with especially with regard to where the dips/peaks are, when your speakers roll off and at which frequencies those peaks/dips occur. Usually people would run different house curves for either music or movies but if you feel you're not getting the visceral feeling, you can definitely PEQ in a desired curve. I personally run my sub a little hot for both movies and music. Flat bass is pretty boring.

Habanero Monk

I don't think you understand what SUM'ing is. You have to measure monophonically to do it correctly. You measure each source speaker, apply EQ, and then SUM the entire setup and apply what ever house curve or BBC dip desired up stream of the individual PEQ applied.

That is why on the signal routing matrix you see on a speaker management system you can apply EQ at the stereo input and EQ on the channel output.

You EQ the channel output first and then apply global correction on the stereo input. The individual PEQ's then track to the master input signal.

Here is a screenshot from a speaker management system showing how this would generally work. This is of course dependent on setup. The other thing to think about: Does the auto correction on an AVR play speakers in tandem or does it do one speaker at a time?

aboroth00

Habanero Monk wrote: »

I don't think you understand what SUM'ing is. You have to measure monophonically to do it correctly. You measure each source speaker, apply EQ, and then SUM the entire setup and apply what ever house curve or BBC dip desired up stream of the individual PEQ applied.

That is why on the signal routing matrix you see on a speaker management system you can apply EQ at the stereo input and EQ on the channel output.

You EQ the channel output first and then apply global correction on the stereo input. The individual PEQ's then track to the master input signal.

Here is a screenshot from a speaker management system showing how this would generally work. This is of course dependent on setup. The other thing to think about: Does the auto correction on an AVR play speakers in tandem or does it do one speaker at a time?

For some reason, I was thinking a sub setup focused on <80hz. But if you want to apply EQ above 80hz into the upper bass region then doing it monophonically would make sense. However, since bass is not stereophonic below 80hz, the primary concern is the in-room response from both speakers. Thus I was also thinking of an external EQ applied once.

This begs the question then to the OP, how are you applying PEQ's? It did not sound as though he was using bass management to apply EQ.

Habanero Monk

aboroth00 wrote: »

For some reason, I was thinking a sub setup focused on <80hz. But if you want to apply EQ above 80hz into the upper bass region then doing it monophonically would make sense. However, since bass is not stereophonic below 80hz, the primary concern is the in-room response from both speakers. Thus I was also thinking of an external EQ applied once.

This begs the question then to the OP, how are you applying PEQ's? It did not sound as though he was using bass management to apply EQ.

Bass may be mono-signal in the terms of 5.1 or 7.1 surround formats as it's own discrete and mastered channel but it is certainly stereo with 2.0 material and you have to treat it as such just like you have to EQ the sub or subs of a 5.2 or 7.2 system.

Agreed it will lose stereophonic localization that low but if you have multiple radiators you have to manage each one monophonically to gain your sum'd response and then apply global EQ etc.

The fact that you really don't hear 80Hz and under as a stereo signal doesn't change the fact about how you properly tune it all together.

If he's taking measurements I can only assume it's so he can adjust. If you have no ability outside of speaker placement to make tweaks there really is not a point, other then academically, to measure it.

pyrocyborg

Well, right now, I have no other way to deal with peaks than to adjust with EQ. I moved the speakers around (well, to enlarge the soundstage), but I'm stuck in a less than ideal rool. Speakers are something like 8'6'' appart and 8 from the listening position, and each speaker is 12'' from the back wall and 7' from sidewalls. I'm currently demoing the LSiM705 (few days left), but in that crappy L shaped room, no speaker could ever sound right.

@aboroth00: I try to use PEQ the same way I would use digital room correction so it could tame bass peaks and have a better overall sound, but I don't want to mess with higher frequencies. However, as I do not know how to make a single filter for two different speakers with different measurements (using REW for measurement and JRiver for EQ-convolution) , someone on the REW forums proposed to use PEQ instead, expecially if I didn't have a lot of filters.

pyrocyborg

Habanero Monk wrote: »

Bass response can be different for each speaker since it is based on room interaction and part of that is the placement. Measure each speaker individually for starters and take a look at the individual response.

Then combine responses.

This would be the same for multiple subwoofers. You will do one at a time.

Gating is a time dependent parameter where after the impulse is played any response past a certain time threshold is ignored (this response is sound coming back at the microphone from a boundary like the floor).

Well, thing is I do not know how to combine responses for both speakers with REW... No tutorial seems to address this topic. I guess Digital room correction is harder than I thougth.

Habanero Monk

Let me check out J-Rivers convolution options. I just use the product straight up.

pyrocyborg

Individual response seems similar in some ways (similar graph) but with peaks and dips at different place (maybe a difference of 10-20 hz) that may be explained by their placement in my room, right?

Still, I do not know if I'll keep the LSiM705. Great speakers, but maybe my integrated amp isn't driving them properly, and maybe some bass frequencies are cancelled in my current room, meaning they won't sound at their best unless I pair them with a good subwoofer and put acoustic treatment.

Maybe I should try the LSiM703. It will be hard to pack the LSiM705 back and maybe the big box vendor won't be happy with the return, but I can't justify to keep a pair of speakers that won't make me smile more than my old LSi7 did, especially at $2300. No speakers were happy in this crappy room, but still, I thought the bigger LSiM705 would shine in there, at least more than the LSi7 did. They do are better than the LSi7, no contest, but given their price, I'm not sure it is that an upgrade considering my room nulify the benefits of having a tower as there is a large frequency band (in the bass region) with a lot of peaks and dips, meaning I would need a subwoofer or two.

I guess I really should have waited till july to buy them (as I move July 1st) as my new room will dictate if the speaker works or not, but I couldn't pass on the deal...

Guess I have few options, which implies, for the most part, to send the LSiM705 back:
- Look for another speaker (tower or bookshelf)
- Buy a pair of bookshelf speakers, stands and a quality subwoofer
- Buy a pair of bookshelf speakers, stands and a power amp that shines at low volume
- Buy a pair of bookshelf speakers, stands and a try to invest in acoustic treatments even if my next room will still be an open area, and that I will move again in a few years.
- Keep the LSiM705 and pray that they will work fine in my next room (in which they will be 2-3 feet away from each wall, instead of 1 feet from the back wall and 7 feet from the sidewalls)
- Any suggestion?