Monolith 13 THX Subwoofer - Question and concerns

[fmw]

That's difficult to nail down for certain as it sounds like you have different rooms for each sub and that's more of a factor than the design. That said, it's not too hard to believe a good, powerful sealed homebrew can wipe the floor with some commercial ported models. That's completely believable.

I've listened to all of them on the home theater. Give me a bigger driver in a sealed box every time.

 

[Vankyra]

Update:

I got my hands on my new Monolith 13! Herniated discs aside, we managed to get it upstairs.

Something that worries me, is that during the first hour, I could hear a sound from the driver itself, even at really low levels. It was distracting and audible from 2 meters or so and felt like something it was damaged behind the cone. But after an hour or so, it loosened up a bit (I guess) .Could it be glue that slowly melts or something? Now I can still hear it, but only during the bigger driver movements (I haven't cranked my main volume more than -30dB's btw so I guess I'm not pushing it more than it could handle). However I have the dynamic eq enabled on my Denon).

Here's a video of the problem: it's a random song (gain knob at THX ref and Main Volume at -45dB's - really low, the driver is barely moving).

20220419_131602.mp4

Visit this link to download: 20220419_131602.mp4

files.fm

 

[Danzilla31]

Update:

I got my hands on my new Monolith 13! Herniated discs aside, we managed to get it upstairs.

Something that worries me, is that during the first hour, I could hear a sound from the driver itself, even at really low levels. It was distracting and audible from 2 meters or so and felt like something it was damaged behind the cone. But after an hour or so, it loosened up a bit (I guess) .Could it be glue that slowly melts or something? Now I can still hear it, but only during the bigger driver movements (I haven't cranked my main volume more than -30dB's btw so I guess I'm not pushing it more than it could handle). However I have the dynamic eq enabled on my Denon).

Here's a video of the problem: it's a random song (gain knob at THX ref and Main Volume at -45dB's - really low, the driver is barely moving).

20220419_131602.mp4

Visit this link to download: 20220419_131602.mp4

files.fm

Is that sound that crackling like sound like rattling that I hear?

If so that is not normal you should contact Monoprice immediately.

The only sound a driver should make on a sub is bass.

Hopefully they can help you troubleshoot and if it's not fixable set you up with a replacement

 

[shadyJ]

Update:

I got my hands on my new Monolith 13! Herniated discs aside, we managed to get it upstairs.

Something that worries me, is that during the first hour, I could hear a sound from the driver itself, even at really low levels. It was distracting and audible from 2 meters or so and felt like something it was damaged behind the cone. But after an hour or so, it loosened up a bit (I guess) .Could it be glue that slowly melts or something? Now I can still hear it, but only during the bigger driver movements (I haven't cranked my main volume more than -30dB's btw so I guess I'm not pushing it more than it could handle). However I have the dynamic eq enabled on my Denon).

Here's a video of the problem: it's a random song (gain knob at THX ref and Main Volume at -45dB's - really low, the driver is barely moving).

20220419_131602.mp4

Visit this link to download: 20220419_131602.mp4

files.fm

It almost sounds like a lead is loose and tapping the cone. I would take the driver out and inspect it. Take pictures and post them here. Look for loose wires.

 

[Pogre]

It almost sounds like a lead is loose and tapping the cone. I would take the driver out and inspect it. Take pictures and post them here. Look for loose wires.

Exactly my first thought. This could be an easy fix.

 

[Vankyra]

Is that sound that crackling like sound like rattling that I hear?

If so that is not normal you should contact Monoprice immediately.

The only sound a driver should make on a sub is bass.

Hopefully they can help you troubleshoot and if it's not fixable set you up with a replacement

It's like a rattling but I can't really be sure.

It almost sounds like a lead is loose and tapping the cone. I would take the driver out and inspect it. Take pictures and post them here. Look for loose wires.

Hmm that I could do. But wouldn't it ruin the Monoprice warranty? I'm hoping it's something easy to solve. I contacted Monoprice, sent them the same video and they immediately asked me if a replacement sub would suit me (!)

Exactly my first thought. This could be an easy fix.

I'm so hoping it's an easy fix..

 

[shadyJ]

I dunno if it void the warranty, but there is already something wrong there, and how much worse can it be made by pulling out the driver to take a peek?

 

[Vankyra]

I was of town for work these days. When I got home I worked the sub for 1 more hour or so and now that sound is completely gone.

I rewatched some bass heavy movie scenes, listened to some bass heavy music aaand I even tried a 10hz sweep (for 4-5seconds at moderate volume of course) and the sub's driver was moving without any issues.

The same song I used on the video I linked you, now plays crystal clear. Monoprice wanted to replace the sub with a new one. Should I let them know that it's all good now, or could it cause any problems in the future?

The thing is that I don't really know how much I can safely push this sub in my room, so that I can stress test it. The gain knob is different than in those from SVS or Arendal. During my tests, I had the knob at THX ref option (where it clicks), used Extended Mode, 3 ports opened, Dynamic Eq enabled and the main volume at -35dB's during movies and even -15dB's for some music tracks.

I ran Audyssey for one more time but I left the gain knob at 12 o'clock. My AVR set the sub trim at -8dB's. From there, during this Preset, how much could I increase the sub trim level and the sub's gain knob?

 

[shadyJ]

I was of town for work these days. When I got home I worked the sub for 1 more hour or so and now that sound is completely gone.

I rewatched some bass heavy movie scenes, listened to some bass heavy music aaand I even tried a 10hz sweep (for 4-5seconds at moderate volume of course) and the sub's driver was moving without any issues.

The same song I used on the video I linked you, now plays crystal clear. Monoprice wanted to replace the sub with a new one. Should I let them know that it's all good now, or could it cause any problems in the future?

The thing is that I don't really know how much I can safely push this sub in my room, so that I can stress test it. The gain knob is different than in those from SVS or Arendal. During my tests, I had the knob at THX ref option (where it clicks), used Extended Mode, 3 ports opened, Dynamic Eq enabled and the main volume at -35dB's during movies and even -15dB's for some music tracks.

I ran Audyssey for one more time but I left the gain knob at 12 o'clock. My AVR set the sub trim at -8dB's. From there, during this Preset, how much could I increase the sub trim level and the sub's gain knob?

You can push this sub really hard, and it is protected. Go ahead and crank the gain to max and then do a sweep. Of course, you don't want to run it on full blast all the time, but it will not bottom out or die from just a momentary sweep.

 

[Vankyra]

You can push this sub really hard, and it is protected. Go ahead and crank the gain to max and then do a sweep. Of course, you don't want to run it on full blast all the time, but it will not bottom out or die from just a momentary sweep.

Wow! I was used to my old PB1000 where at -30dB's MV, Dynamic Eq on and +6dB's boost, it would chuff badly and seemed that it was reaching its limits.

I've read that many people run their subs hot at around +3dB's to 6dB's. The more capable the sub, the more bass boost it can handle as it seems.

 

[shadyJ]

Wow! I was used to my old PB1000 where at -30dB's MV, Dynamic Eq on and +6dB's boost, it would chuff badly and seemed that it was reaching its limits.

I've read that many people run their subs hot at around +3dB's to 6dB's. The more capable the sub, the more bass boost it can handle as it seems.

Port chuffing isn't exactly reaching its limits (unless you count sound quality). Chuffing just means that the air in the port has lost its cohesion as a mass and is turning chaotic. That doesn't necessarily mean the sub is in danger or is about to be destroyed. It's normally a pretty good sign that you should probably back off in the volume, but in these days of exacting DSP limiters, most subs can get into chuffing without putting themselves in danger.