Null at 70-85 hz when I play a sweep

S

Sky1

Audioholic Intern
Hey guys, I am trying to figure out why I might be experiencing a null between 70-85hz when I play a sound sweep I found on Youtube.
Testing in Stereo mode with Sub
Speakers are SVS Prime Towers, subwoofer is a Klipsch R10sw.
Do I need to switch the phase switch or, move it? IDK, I currently have the sub so the driver is pointing into the front corner of the room about 3 ft from the wall.
My listening position is pretty much the ideal location for stereo.
Can someone recommend what I should try and what software I might want to use?
My receiver is a Dennon AVR 3300?? Running Dolby Atmos 7.1.2 tuned with Audyssey xt32 I believe. My floors are real 3/4" hardwood and a vaulted ceiling. Plenty of seating and carpets in the room (no echo) Prime seating is about 13' from the speakers and sub.
Also, when I went to listen to a number of subs, I chose the 10" because it sounded more punchy and responsive than the 12" I was planning to get a second one but never did. The 10" 300watt ported sub provides sufficient sound level for the room but it is a cheap sub with no DSP but no apparent issues with it.
Considering either getting a second subwoofer (only $220) or pulling out what I got and going with Pr of SB2000's or 3000's
I have a great wife who says "Get what you want" but my inner cheapskate is saying try another Klipsch 10 before laying out 2 grand on subs as the improvement may not justify that much price difference. Besides I may want to upgrade to 7.2.4 Atmos later next year.
We listen to music and movies at medium to moderate levels, nothing super loud as our pets go crazy when I do.

I would like to try fixing the null before buying new equipment.
 
S

Sky1

Audioholic Intern
sorry, left off that I am running sub in LFE mode, crossover is all the way over in LFE position on the sub.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
Just guessing, but it sounds like a simple XO cancellation. Pretty common. Try adding one foot at a time to the sub distance and resweep. Then see what the graphs looks like. Can you post them? Are you using REW?
For the sub, what you most likely were hearing, was some distortion(not the same kind as speakers). Also, if you were listening in a store, I would take any impressions with a grain of salt. As stores are usually set up poorly for testing subs, and it’s ALWAYS different than in your house. Imo, you should add the best sub you can afford, and start saving for a second one right away.
How big is the room, and what is your current gearb
 
ryanosaur

ryanosaur

Audioholic Spartan
Klipsch subs are not really known as great performers. But that's not your problem here. I would always recommend multiple subs as it will even out your bass response in the room. If you want to take your experience to another level, step up to the better quality Subs from SVS, Hsu, Outlaw, and Monoprice Monolith... also Subs that get mentioned a lot are Rythmik and PSA.

To your problem, acoustics are a b!tch. It could be as Bill suggested, you could also be getting a cancellation due to the soundwave reflecting off of something and bouncing back to the source (so you are looking at a reflection between 12' and 14' away, or half of that.) Just a possibility... and there are many. ;)

How did you select placement? If you did not do the subwoofer crawl, I highly recommend it. It is a crude technique, but it will teach you a fair amount about how Low Frequencies behave in your room. If you do it, look for the best 2-3 locations where the bass sounds best, and listen for the subtle differences you may hear as you move around the room. Keep an open mind about potential homes for your Sub(s). Getting the best performance doesn't always mean corners or front wall placement.

Other things to try:
Move your seating, subwoofer, and or speakers slightly. Inches can make a difference. You could just have you seat in a bad spot in the room, for example. My system was set up symmetrically until I discovered a problem, I moved one speaker by about 1.5" and changed the toe-in slightly to fix it. Now my mains and Subs are each different distances from each other, and from me, and in this asymmetrical arrangement, I found better response.

As Bill asked, please give room dimensions. Photos can be helpful, too. Also, figuring out the actual open room volume for your subwoofer... l x w x h... how much space it has to work to fill... is important. :)

Cheers!
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
Oh. Guess I can’t read. Klipsch 10”. No coffee yet...lol
 
S

Sky1

Audioholic Intern
Gosh, I haven't used this Website in years and it still Rocks! Thank you so much for the prompt reply.
My room is 19' deep by 14' wide Vaulted ceiling peak is I think 12' not very sloped and has that popcorn stuff on it.
I do not have any specialized equipment for analysis.
We plan to move soon to a much larger place. My wife is onboard with upgrades but I think the move won't happen until the middle of next year. So if I get something new in the way of subs, I want them to be able to accommodate the new place probably a similar sized room.

I am going to run another sweep with the phase reversed on my sub and see what happens. I have a Youtube channel, can upload a video of what I got and show what is going on. My system sounds overall pretty good and LFE from movies is plentiful but have always struggled with mid-low bass (music) since we moved into this house with the hardwoods and all. It is just not punchy like it should be.
I setup a Edifier SB350dbs 2.1 system on my computer here in my office. The bass from this system is way more punchy than in my living room. Its almost embarrassing that this little system has punchier kick than my home surround system.
 
ryanosaur

ryanosaur

Audioholic Spartan
Gosh, I haven't used this Website in years and it still Rocks! Thank you so much for the prompt reply.
My room is 19' deep by 14' wide Vaulted ceiling peak is I think 12' not very sloped and has that popcorn stuff on it.
I do not have any specialized equipment for analysis.
We plan to move soon to a much larger place. My wife is onboard with upgrades but I think the move won't happen until the middle of next year. So if I get something new in the way of subs, I want them to be able to accommodate the new place probably a similar sized room.

I am going to run another sweep with the phase reversed on my sub and see what happens. I have a Youtube channel, can upload a video of what I got and show what is going on. My system sounds overall pretty good and LFE from movies is plentiful but have always struggled with mid-low bass (music) since we moved into this house with the hardwoods and all. It is just not punchy like it should be.
I setup a Edifier SB350dbs 2.1 system on my computer here in my office. The bass from this system is way more punchy than in my living room. Its almost embarrassing that this little system has punchier kick than my home surround system.
Is that room open to other areas, or closed off?
What is the low height of the cathedral ceiling? 8’ would be common... ;)
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
Gosh, I haven't used this Website in years and it still Rocks! Thank you so much for the prompt reply.
My room is 19' deep by 14' wide Vaulted ceiling peak is I think 12' not very sloped and has that popcorn stuff on it.
I do not have any specialized equipment for analysis.
We plan to move soon to a much larger place. My wife is onboard with upgrades but I think the move won't happen until the middle of next year. So if I get something new in the way of subs, I want them to be able to accommodate the new place probably a similar sized room.

I am going to run another sweep with the phase reversed on my sub and see what happens. I have a Youtube channel, can upload a video of what I got and show what is going on. My system sounds overall pretty good and LFE from movies is plentiful but have always struggled with mid-low bass (music) since we moved into this house with the hardwoods and all. It is just not punchy like it should be.
I setup a Edifier SB350dbs 2.1 system on my computer here in my office. The bass from this system is way more punchy than in my living room. Its almost embarrassing that this little system has punchier kick than my home surround system.
This is interesting. We’ve had a couple people post this year with edifer systems that were having problems with their “subs” and it sounded like they were coming apart with bass heavy music.

Anyway, that is telling in a couple ways. It speaks to the effects of near field placement, and that the Klipsch is not up to task. It might seem that bass is good in movies, but you’d be amazed at what a great sub can do that’s properly integrated. That room isn’t huge, but definitely big enough to need more/better. Still, curious about your sweeps.
 
highfigh

highfigh

Audioholic Overlord
Gosh, I haven't used this Website in years and it still Rocks! Thank you so much for the prompt reply.
My room is 19' deep by 14' wide Vaulted ceiling peak is I think 12' not very sloped and has that popcorn stuff on it.
I do not have any specialized equipment for analysis.
We plan to move soon to a much larger place. My wife is onboard with upgrades but I think the move won't happen until the middle of next year. So if I get something new in the way of subs, I want them to be able to accommodate the new place probably a similar sized room.

I am going to run another sweep with the phase reversed on my sub and see what happens. I have a Youtube channel, can upload a video of what I got and show what is going on. My system sounds overall pretty good and LFE from movies is plentiful but have always struggled with mid-low bass (music) since we moved into this house with the hardwoods and all. It is just not punchy like it should be.
I setup a Edifier SB350dbs 2.1 system on my computer here in my office. The bass from this system is way more punchy than in my living room. Its almost embarrassing that this little system has punchier kick than my home surround system.
That popcorn crap doesn't help much, if at all. You need to look at a room mode calculator and learn to interpret it. Mark the speaker locations with painter's tape (the kind that's easy to remove) and move your speakers in small increments. Start by turning off the subwoofer and do another sweep. If the dip still exists, make sure the main speakers aren't centered on the wall where they live. Being off-center helps. If the dip disappears, make sure the crossover frequencies are what the room requires. Mark the sub's location and move it, too. Obviously, it can't go just anywhere, but find acceptable spots and try it in each.

Your AVR may have distance settings for the speakers- use it and set it to the smallest increments. Only work with the high pass at first and really listen to the placement of the instruments and voices- you should be able to hear a difference when one speaker's distance setting is changed by .1 or .2 feet. If you can't, listen with your eyes closed- you should be able to hear this but you need to eliminate noise from everything else.

Once you find the sweet spot for the speakers and the distance settings, add the sub and repeat. The distance settings affect when the sound comes from the speakers, therefor, it changes the time relationship for the sound coming from the speakers and this works the same way as moving one of them but it doesn't affect the way the energy interacts with the room- that can only be changed by moving the speakers and changing the acoustical properties of the walls that are reflecting the sound.
 
S

Sky1

Audioholic Intern
yes the low end of the ceiling about 8' and hallway to bedtooms, a short hall to the front door and a large 8' octagonal archway to large Kitchen/Dining area same size as this room.
I might add the Null is huge
 
Last edited:
S

Sky1

Audioholic Intern
I switched the phase, no more null. It was going from 74db down to 62, now that I changed the phase it dips to 72 at the lowest from 74.
Wifey says to buy the subwoofer I want. Dual SB2000's, SB3000? I think the PB3k might be too big plus I want piano gloss to match my other speakers.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
I switched the phase, no more null. It was going from 74db down to 62, now that I changed the phase it dips to 72 at the lowest from 74.
Wifey says to buy the subwoofer I want. Dual SB2000's, SB3000? I think the PB3k might be too big plus I want piano gloss to match my other speakers.
Imo, get ported. The sb2k is good, but it’s not really loud, and like all
Sealed subs, just don’t deliver the same experience below 35hz or so.
I vote for two PC2K pros. Or take a look at HSU and Rythmik. Monolith too.
 
S

Sky1

Audioholic Intern
oh, cant go with those, I have cats looks too much like a scratching post! That is why I leave the grills off on my towers, just cant trust them. So PB2000 better than a SB3000 you think, I don't play loud, just want to feel the effects when watching movies and want music bass that is not muddy
 
William Lemmerhirt

William Lemmerhirt

Audioholic Spartan
oh, cant go with those, I have cats looks too much like a scratching post! That is why I leave the grills off on my towers, just cant trust them. So PB2000 better than a SB3000 you think, I don't play loud, just want to feel the effects when watching movies and want music bass that is not muddy
Yes. Definitely PB then.
FWIW two of my subs are pc12pluses. They only look like scratching posts to people. Three different cats over time and not even one messed with them. I understand reticence but my experience has been good. If you give them something REALLY good to scratch like a sisal tower etc they won’t care. Or do they just shred everything?
 
S

Sky1

Audioholic Intern
They have scratching posts and pads but not sure if they will attack these. I had a friend back in high school that had these awesome speakers. , went over his place one day and his speaker grills were shredded, part of the cones were destroyed as well, was a sad day.
Anyway, looking at the construction of these PC2000's maybe I could wrap them with rope an make them a scratching post an cat tree? But man, they are very obtrusive IMO.Also my worry about ported speakers are critters getting in there making it their home. I just watched a review on Youtube where the guy demo'd the speakers with and without the plugs, now I see the Ports are definitely better for movies with the LFE sounds that you feel more than you hear. I am watching the Movie Memorial Day right now with my 10" Klipsch Sub it is doing a decent job for the gunfire and some explosions but not shaking the floor or walls. I might try boosting it in the AVR and see what happens.
 
ryanosaur

ryanosaur

Audioholic Spartan
Ported vs Sealed for Movie or Music...
This.
Myth.
Needs.
To.
Die.

There is nothing wrong with a good quality ported sub: they perform equally well for Music AND Movies. Unless you are in a closed room less than 3000cu.ft, and using 3-4 sealed subs, there is almost no competition. Even then, I would likely choose the ported option. :)
 

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