Monolith 15” THX Sub issues - worse than PL-200? - Page 3 - AVS Forum | Home Theater Discussions And Reviews
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post #61 of 72 Old 04-02-2019, 01:56 PM
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Quote:
Originally Posted by craig john View Post
Hi Suke,

The one clue I found in your description of the problem is that the lowest bass is present and "smoother, without distortion" yet the midbass was missing. I have seen exactly this problem before when the subwoofer was mis-timed, and out-of-phase with the speakers. This cause a significant cancellation of the frequencies around the crossover point, which would be smack-dab in the wheelhouse of the mid-bass. Here is a measurement of my own system with the subs both mis-timed and properly timed:


You can easily see in the cyan trace that there is a wide, deep dip from 63 to 150 Hz. This is over 1 octave wide and the deepest part of the dip is over 20 dB down from the average. I can tell you that this sounds like the bass is completely "missing." This occurs because the subwoofer drivers are moving outward while the speaker woofer drivers are moving inward. The simultaneous positive/negative deflections causes a complete cancellation of the sound. By re-timing the driver movements so they are in-phase with each other, (sub drivers and speaker woofer drivers both moving inward and outward at the same time), there is no cancellation and that yields the flatter response seen in the green trace.

I did this simply by changing the subwoofer "Distance" setting the receiver. The cyan trace has the subwoofer Distance at 10.6 ft. and the green trace has the subwoofer Distance at 14.8 ft. The Distance setting is actually a "delay" setting and by lengthening the Distance of the subs, you are effectively delaying the speakers longer so the waves from both sets of drivers arrive at the same time, (in-phase with each other).

In your case, what could cause the two subs to need different Distance/Delay settings? There is likely different latency in each sub amplifier. One sub may do more "processing" of the signal, using different DSP modes, or using analog Low Pass Filters/High Pass Filters, etc. Processing takes time, (a few milliseconds), enough time that the arrival times at the listening position are off by a few milliseconds. That is enough time to make the subs and speakers out-of-phase. No matter what's causing it, it can be corrected by re-timing the subs using the Subwoofer Distance setting in the receiver. I suggest you start by adding 3 or 4 feet to the Monolith sub Distance. See if that improves the bass. If it does, then keep playing with more or less Distance until you have it optimized as best as possible to your ear.

Better yet, get some measuring equipment and measure your response to get it as optimal as possible.

Good luck. I hope the solution is as simple as this one setting.

Craig
Great info Craig.

So did the microphone based EQ just "blow it" on your receiver when it came to the distance setting?

I'm aware that EQ generally has the subwoofer distance several feet further back in the menu than the actual measurement with a measuring tape but "assumed" the EQ would get it correct.

I'm pretty sure mine is OK but might play with it.

My sub has microphone self EQ which I run prior to Audyssey in the AVR.
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post #62 of 72 Old 04-07-2019, 10:50 PM
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Oh yay, it's not just me. I bought the Monolith 15" THX back in December, and immediately noticed the same issues with lack of volume output/ability to fill the room (presence). There's no oomph like one would receive at the theaters.
I've tried a couple different receivers, multiple settings, different RCA cables, RCA to Balanced, but came back to the same conclusion: the only almost acceptable configuration was max volume on the sub w/THX disabled, and +12db (max) for the subwoofer on the receiver; while also having to turn the rest of the speakers to -10db (Klipsch, highly sensitive). Even so, I'd have to crank the volume way up on the receiver. This almost yielded desired results, but left me no room to adjust the speakers. I RMA'd it, unfortunately the replacement has the same issue. Both have that popping noise when they switch on from standby that someone else mentioned. My experiences are nothing like were described by the two major reviews for the subwoofer. So, currently I'm at a loss of where to go from here myself. :/ Disappointment is the best word to describe my feelings towards it.
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post #63 of 72 Old 04-08-2019, 07:45 AM
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Originally Posted by Ansune View Post
Oh yay, it's not just me. I bought the Monolith 15" THX back in December, and immediately noticed the same issues with lack of volume output/ability to fill the room (presence). There's no oomph like one would receive at the theaters.
I've tried a couple different receivers, multiple settings, different RCA cables, RCA to Balanced, but came back to the same conclusion: the only almost acceptable configuration was max volume on the sub w/THX disabled, and +12db (max) for the subwoofer on the receiver; while also having to turn the rest of the speakers to -10db (Klipsch, highly sensitive). Even so, I'd have to crank the volume way up on the receiver. This almost yielded desired results, but left me no room to adjust the speakers. I RMA'd it, unfortunately the replacement has the same issue. Both have that popping noise when they switch on from standby that someone else mentioned. My experiences are nothing like were described by the two major reviews for the subwoofer. So, currently I'm at a loss of where to go from here myself. 😕 Disappointment is the best word to describe my feelings towards it.
Yeah, I'm not sure what's happening with some of the setups and performance some are getting. I have the same sub and it hits hard in my 2856 cu.ft. room with an opening to dining room and kitchen, and on wood floors over a concrete slab. I'm using a 2009 Pioneer Elite Receiver (VSX-01TXH) and I used the mic to run MCACC for all speakers and the sub.

On the AVR: trim set at -7; crossover for all speakers at 80Hz; speakers set to small; LFE set at 0.

On the M15: level knob at 3 o'clock; Extended EQ used; crossover switch set to off and knob turned to 160Hz; phase set at 0; 1 port plugged.

Though, I'm using 3 port mode right now to see if I like it better.

With those settings and the distance and calibration my AVR set, I'm very impressed. I was playing the free month trial of Call of Duty: Blackout yesterday on my PS4 Pro with the Main Volume on the AVR at -15dB and the bass in that game sounds great and hits hard. I turned the bass boost on in the game's settings. So when I read people can't get the sub to perform... I'm at a loss. I guess just make sure the crossover switch on the sub is set to THX (off). Unless you're trying the cascading crossover effect. Maybe I just play my system louder than some. I usually watch movies around -10dB to -15dB. Unless it's something like Infinity War. Then I have to watch at -5dB because the movie is mixed low.

And the faint click noise the sub makes when awakened from standby is nothing to worry about. I only hear it when I first turn all my devices on and start playing content.
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post #64 of 72 Old 04-08-2019, 08:18 AM
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One thing I found when running REW checking the Monolith 15 is that I got the best results with the crossover switch off (set to THX). When it was on, SPL took a nose dive around 90Hz and beyond.
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post #65 of 72 Old 04-09-2019, 12:06 PM
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Quote:
Originally Posted by Spewdom View Post

On the AVR: trim set at -7; crossover for all speakers at 80Hz; speakers set to small; LFE set at 0.

On the M15: level knob at 3 o'clock; Extended EQ used; crossover switch set to off and knob turned to 160Hz; phase set at 0; 1 port plugged.
Mine is set the same with the exception of all ports open.
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post #66 of 72 Old 04-10-2019, 06:42 AM
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There are differences in input sensitivities on the different amps. One setup will not be the same for another. It sounds like what everyone already mentioned, you may have a peak with the BIC and a null with the Monolith. You need to utilize that UMIK a you purchased.

As for the 4 18s not performing like a 10, you need to read and learn to setup properly. Having more low bass than mid bass is not the PSA subs thing, most drivers have much more midbass than low bass, except for mine lol.
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post #67 of 72 Old 05-24-2019, 09:12 AM
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Só any conclusions from the OP? Did you get your original Mono replaced ? Are you happy with it now ?
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post #68 of 72 Old 05-24-2019, 10:36 AM
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I was probably one of the first Mono 15 customers on the forum and my duals have been running strong with no issues. There are times where my whole house shakes. It sucks for those that have issues, but I will say that that subwoofer placement and tuning is essential to maximize performance.
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post #69 of 72 Old 05-24-2019, 10:41 AM
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Quote:
Originally Posted by ack_bk View Post
I was probably one of the first Mono 15 customers on the forum and my duals have been running strong with no issues. There are times where my whole house shakes. It sucks for those that have issues, but I will say that that subwoofer placement and tuning is essential to maximize performance.
Yeah, I get great performance from my Monolith 15. Movies sound amazing. I just have a second preset for when I listen to music and push my AVR sub trim to +2dB. I know it's recommended not to go in positives, but it sounds great with kick drums in metal music, and is only used when I listen to music without a lot of sub 30Hz frequencies. Made up for losing the distorted midbass peaks the BIC had.
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post #70 of 72 Old 09-27-2019, 12:34 PM
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Originally Posted by tedhontz View Post
Just out of curiosity, what kind of design is your PL-200? Downfiring or front firing? Ported in the front or ported in the back? I own an electronics company and many subs pass through my warehouse on a weekly basis. When testing everything, I am sometimes surprised at how good or bad a product is considering the original pricing. I tested a BIC and I "think" it was a PL-200. I was amazed at the sub. I recently upgraded all my subs in my home theater room at home. I purchased (4) Power Sound Audio subwoofers V1811 and they each contain a 18" driver and are front firing and front ported. My complaint with them is that there is hardly any bass! I started with a Denon receiver. When running the mic calibration I set the subs to 15% gain and then when all setup, I kept turning up the gain on all subs until happy. I had my subs gains set at 90% and still wasn't enough bass. So then I turned up the gain in the receiver.

I went to the Thread for Power Sound Audio owners. Power Sound Audio is a sponsor of this AVS site and an AVS vendor plus the two owners of the company are active on the thread as well. I'm having the same problem with all four of my subs. On really really low ultra low frequencies in some movies, the subs shake the room. But when listening to music, they are very disappointing compared to my old subwoofer setup. Of course when I go into the Power Sound Audio owners thread and complain that I spent $6000 and have no bass, instead of any kind of help at all, I get chased out of the very biased room including by the company owners. I bought a different receiver and same thing, I have to crank the gain on all the subs and crank up the gain in the receiver settings and I still don't like my results. So now I have a third receiver that I am waiting to hookup and try. I do get bass on certain bass frequencies but only on big sloppy frequency sounds. But I am missing the tight bass and pounding that I was told I would get.

My point is, if you go to a Monolith owners thread, you'll be dealing with only people that LOVE Monolith subs. I don't like Monolith subs. Heck you can even go to a BIC thread and those owners will tell you how great the BIC subs are. And for the money, they are. It's all about opinion. I've made every adjustment possible to my 4 PSA V1811 subs and they still are terrible. They aren't the worst subs I've ever heard for movies. It does sound better than some $200 subs I've heard, on movies. But I'd take BIC PL-200 over my subs. I wish I would've made a different choice and I'm seriously thinking of taking a huge loss and getting rid of my PSA subs and getting something different.

I have noticed better luck with certain "designs" of subs. For example, down firing subs with rear ports sound better than front firing subs with front ports. Sealed subs, if you have two of them, and put one in the front corner of your room and one in the opposite back corner in the room, that sounds amazing as well. So you need to take that into account as well. Here is a pic of the two front subwoofers I have.
This definitely sounds like you are used to a "distorted" unbalanced sound from your subwoofers. I went through the same thing. I used to use dual "budget" Klipsch R12SW subwoofers. These subwoofers exaggerate the mid bass, similar to how the BIC or any other low end "budget" subwoofer would. I then upgraded to dual SVS PC4000's, they had thousands of watts on tap, a MUCH better driver and yet they sounded tamed down and "less audible". They of course performed better in the low end bass, but they still seemed less audible. What it ended up being is that my ears were accustomed to exaggerated unbalanced bass that a low end subwoofer will give you. Higher end subwoofers offer you accurate bass with little to no distortion. I guarantee you, that if you take a UMIK-1, download REW and measure both subwoofers, the clean no distortion bass WILL measure louder. Low end subwoofers provide you with bass that a lot of people refer to as boomy, that is that sound when you think your subwoofer is just filling the room with awesome bass...but it isn't, that is just distortion and inaccuracy. Now, I could never go back to low end subwoofers, sure they may SOUND louder in some frequencies, but I can tell it is not clean proportionate bass. It is not how the soundtrack is supposed to sound. I have used REW to measure subwoofers and sometimes your ears are deceiving you, the louder SOUNDING bass isn't always louder. The clean low distortion bass is actually louder when measured in DB's.
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post #71 of 72 Old 09-28-2019, 01:05 PM
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Quote:
Originally Posted by craig john View Post
Hi Suke,

The one clue I found in your description of the problem is that the lowest bass is present and "smoother, without distortion" yet the midbass was missing. I have seen exactly this problem before when the subwoofer was mis-timed, and out-of-phase with the speakers. This cause a significant cancellation of the frequencies around the crossover point, which would be smack-dab in the wheelhouse of the mid-bass. Here is a measurement of my own system with the subs both mis-timed and properly timed:


You can easily see in the cyan trace that there is a wide, deep dip from 63 to 150 Hz. This is over 1 octave wide and the deepest part of the dip is over 20 dB down from the average. I can tell you that this sounds like the bass is completely "missing." This occurs because the subwoofer drivers are moving outward while the speaker woofer drivers are moving inward. The simultaneous positive/negative deflections causes a complete cancellation of the sound. By re-timing the driver movements so they are in-phase with each other, (sub drivers and speaker woofer drivers both moving inward and outward at the same time), there is no cancellation and that yields the flatter response seen in the green trace.

I did this simply by changing the subwoofer "Distance" setting the receiver. The cyan trace has the subwoofer Distance at 10.6 ft. and the green trace has the subwoofer Distance at 14.8 ft. The Distance setting is actually a "delay" setting and by lengthening the Distance of the subs, you are effectively delaying the speakers longer so the waves from both sets of drivers arrive at the same time, (in-phase with each other).

In your case, what could cause the two subs to need different Distance/Delay settings? There is likely different latency in each sub amplifier. One sub may do more "processing" of the signal, using different DSP modes, or using analog Low Pass Filters/High Pass Filters, etc. Processing takes time, (a few milliseconds), enough time that the arrival times at the listening position are off by a few milliseconds. That is enough time to make the subs and speakers out-of-phase. No matter what's causing it, it can be corrected by re-timing the subs using the Subwoofer Distance setting in the receiver. I suggest you start by adding 3 or 4 feet to the Monolith sub Distance. See if that improves the bass. If it does, then keep playing with more or less Distance until you have it optimized as best as possible to your ear.

Better yet, get some measuring equipment and measure your response to get it as optimal as possible.

Good luck. I hope the solution is as simple as this one setting.

Craig
Excellent detective work! This probably impacts more systems than people realize. Reading through this thread, I know something ‘is going on’. When I connected my PB4000 and played a movie for the first time (Rampage, I believe) I literally scared myself. There was no confusion as to whether my subwoofer was on.

SPEAKERS: 7.1 Def Tech Mythos ST L/R | Mythos 10 C | Mythos Gem XL S/R
SUB: SVS PB4000

RECEIVER: Cambridge Audio 751R
DISPLAY: Sony 75" XBR900E SOURCES: Sony UBP-X800 4K disc player, PS3, PS4
MISC: Harmony Elite remote
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post #72 of 72 Old 10-09-2019, 10:54 PM
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Hey @C4Suke , how was the replacement Monolith 15? I'm having an issue similar to the one you had.

https://www.avsforum.com/forum/113-s...l#post58667008
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