Monoprice Monolith THX-365T Mini-Tower and THX-365C Center Speaker Review

Kingnoob

Kingnoob

Audioholic Samurai
Hard to say. It is THX Ultra certified, so it should be able to hit 105 dB peaks in a 3,000 square foot room at a listening distance of 12 ft from the speaker with minimal distortion. But who knows how they derived that. I will say it can certainly get louder than a traditional bookshelf speaker, probably on the level of a three-way tower.
Wow well that’s loud regardless of wattage , it’s like a professional audio speaker loud. ??

If they sell enough maybe the will make a larger version? That sub is powerful the new double 15” hopes someday I can afford it
Ultimate bass lover !! si ht15 dvc.
Cannot get anymore big subs until I can move out though ...
Free the reptile aliens
 
S

shadyJ

Speaker of the House
Staff member
Wow well that’s loud regardless of wattage , it’s like a professional audio speaker loud. ??

If they sell enough maybe the will make a larger version? That sub is powerful the new double 15” hopes someday I can afford it
Ultimate bass lover !! si ht15 dvc.
Cannot get anymore big subs until I can move out though ...
Free the reptile aliens
That's loud but not pro-audio loud. Live sound speakers could probably hit 115 to 125dB within those limits. But listen at those volume levels for more than a moment and you risk permanent hearing damage.
 
Kingnoob

Kingnoob

Audioholic Samurai
That's loud but not pro-audio loud. Live sound speakers could probably hit 115 to 125dB within those limits. But listen at those volume levels for more than a moment and you risk permanent hearing damage.
Yeah wonder how many people who go to concerts leave deaf ...


Ultimate bass lover !! si ht15 dvc.
Free the reptile aliens
 
A

Adam2434

Audioholic Intern
Posted the following on AVS, but thought I might get some input here possibly because it involves the Monolith THX center. This is more of a curiosity and not something I'm really too concerned about.

Looking at Audyssey MultEQ app “before” plots for 2 different center channel speakers, I’m curious about what might be causing dips in the 200-600 Hz range. From other threads, I’ve learned that the MultEQ “before” subwoofer plots track with REW plots, but not sure how accurate the MultEQ “before” plots are for other channels in the 200-600 Hz range.

So, this topic kind of assumes that the MultEQ app “before” plots for the center are accurate enough to make some observations in the 200-600 Hz range. I’m not obsessing over these plots, but really just have some intellectual curiosity about them, wondering if they show anything meaningful about the speaker performance and interaction with the room.

The first plot is the new center speaker, the Monolith THX 3-way. The second plot is my old center, a Polk CS400i 2.5-way (tapered crossover on the two 6.5” drivers). Mic positions were very similar for both plots: 8 mic positions centered around the MLP, which is in-line with the center speaker.

I guess I was expecting a bit better “before” plot with the Monolith THX center, given the 3-way design and very good measurements in the Audioholics review. The “before” plots show ~7 dB dips in the 200-600 Hz range. The old Polk center shows a larger dip centered around 200 Hz.

I attached a couple pics of the center speaker position in the room. It is flush with the shelf and is angled up a bit with rubber bumpers. The shelf is about 23” off the ground. My processor and one amp are on the same shelf, a few inches back from the shelf edge.

Anyway, assuming the “before” plots are accurate enough, I’m just curious about what could be causing dips in the 200-600 Hz range. Maybe a comb filtering effect from floor or ceiling bounce? Or something else?

Just curious to hear some thoughts on this.
 

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everettT

everettT

Audioholic Spartan
Posted the following on AVS, but thought I might get some input here possibly because it involves the Monolith THX center. This is more of a curiosity and not something I'm really too concerned about.

Looking at Audyssey MultEQ app “before” plots for 2 different center channel speakers, I’m curious about what might be causing dips in the 200-600 Hz range. From other threads, I’ve learned that the MultEQ “before” subwoofer plots track with REW plots, but not sure how accurate the MultEQ “before” plots are for other channels in the 200-600 Hz range.

So, this topic kind of assumes that the MultEQ app “before” plots for the center are accurate enough to make some observations in the 200-600 Hz range. I’m not obsessing over these plots, but really just have some intellectual curiosity about them, wondering if they show anything meaningful about the speaker performance and interaction with the room.

The first plot is the new center speaker, the Monolith THX 3-way. The second plot is my old center, a Polk CS400i 2.5-way (tapered crossover on the two 6.5” drivers). Mic positions were very similar for both plots: 8 mic positions centered around the MLP, which is in-line with the center speaker.

I guess I was expecting a bit better “before” plot with the Monolith THX center, given the 3-way design and very good measurements in the Audioholics review. The “before” plots show ~7 dB dips in the 200-600 Hz range. The old Polk center shows a larger dip centered around 200 Hz.

I attached a couple pics of the center speaker position in the room. It is flush with the shelf and is angled up a bit with rubber bumpers. The shelf is about 23” off the ground. My processor and one amp are on the same shelf, a few inches back from the shelf edge.

Anyway, assuming the “before” plots are accurate enough, I’m just curious about what could be causing dips in the 200-600 Hz range. Maybe a comb filtering effect from floor or ceiling bounce? Or something else?

Just curious to hear some thoughts on this.
It dosent look bad for the region it's at, definitely better than the other center. Getting a flat response in room vs outdoor or chambered indoors, isn't that common. I think it looks good and wound take much cut to even it out, if you thought it needed.
 
ryanosaur

ryanosaur

Audioholic Overlord
Considering those plots aren't smoothed, the first one looks better than the Polk (second one?).
Keep in mind that the rooms Schroeder Frequency is at play below roughly 300Hz. The room is a resonant chamber that low and will behave differently than above the Schroeder Frequency.
My main comment on your placement would be to move the speaker ever so slightly more forward so that the Baffle is about 3/4-1" in front of the edge of the shelf. I don't necessarily think that what you are seeing is diffraction effects caused by the gear there, but it is a possibility. Likewise, it could be a cancellation effect caused by another speaker or reflected soundwave coming back at that as the source. But even then... it's not like you have a -20 or -30 dB suckout happening.
 
S

shadyJ

Speaker of the House
Staff member
Posted the following on AVS, but thought I might get some input here possibly because it involves the Monolith THX center. This is more of a curiosity and not something I'm really too concerned about.

Looking at Audyssey MultEQ app “before” plots for 2 different center channel speakers, I’m curious about what might be causing dips in the 200-600 Hz range. From other threads, I’ve learned that the MultEQ “before” subwoofer plots track with REW plots, but not sure how accurate the MultEQ “before” plots are for other channels in the 200-600 Hz range.

So, this topic kind of assumes that the MultEQ app “before” plots for the center are accurate enough to make some observations in the 200-600 Hz range. I’m not obsessing over these plots, but really just have some intellectual curiosity about them, wondering if they show anything meaningful about the speaker performance and interaction with the room.

The first plot is the new center speaker, the Monolith THX 3-way. The second plot is my old center, a Polk CS400i 2.5-way (tapered crossover on the two 6.5” drivers). Mic positions were very similar for both plots: 8 mic positions centered around the MLP, which is in-line with the center speaker.

I guess I was expecting a bit better “before” plot with the Monolith THX center, given the 3-way design and very good measurements in the Audioholics review. The “before” plots show ~7 dB dips in the 200-600 Hz range. The old Polk center shows a larger dip centered around 200 Hz.

I attached a couple pics of the center speaker position in the room. It is flush with the shelf and is angled up a bit with rubber bumpers. The shelf is about 23” off the ground. My processor and one amp are on the same shelf, a few inches back from the shelf edge.

Anyway, assuming the “before” plots are accurate enough, I’m just curious about what could be causing dips in the 200-600 Hz range. Maybe a comb filtering effect from floor or ceiling bounce? Or something else?

Just curious to hear some thoughts on this.
There is no doubt that the in-room Monolith response is better. Smoother mids, much smoother treble, and not as pronounced dip in upper bass. The dip itself is probably due to ground bounce cancellation among other room cancellations. It could also be partly due to lobing cancellation from the horizontally oriented bass drivers, if that measurement involves off-axis responses.
 
Pogre

Pogre

Audioholic Slumlord
I'd be very surprised to see any speaker measure flat in room without any eq. It's more a reflection of the room acoustics than it is the speaker, tho the Monolith definitely looks better.
 
A

Adam2434

Audioholic Intern
Thanks for the input, guys.

I do plan to move the center forward a bit so that the baffle is slightly in front of the shelf edge. I don't expect much of an effect, but it can't hurt. I'll probably do this and then do another calibration when the Monolith floorstanders are available (planning to buy them).

Those "before" plots were made by the MultEQ app (Monolith first, Polk CS400i second) and I use a pretty tight mic spacing for the calibrations, so the plots are pretty much on axis with the center.

With the app, if I apply correction to 800 Hz, the Monolith "after" plot shows a flattening of the response in the 200-600 Hz region, so yes, applying correction (XT32) is an option. I usually try to apply minimal correction to the LCR, by limiting the correction range to 350 Hz, but the Monolith center would need correction to about 800 Hz, if I want to flatten the region with dips.

Assuming the dips are from ground bounce, interesting that 2 different models in same location would produce different ground bounce effects and/or other cancellation effects. But, then again, they are different designs: a sealed 3-way vs. a ported 2.5-way.

I do not expect a flat "before" response in-room, although I have seen some better looking app "before" center plots from others. A guy with a KEF Reference center comes to mind.

BTW, the Monolith center sounds great - no complaints. I think is has a bit of an edge on the Polk for vocal clarity, but not a huge difference from my initial impressions.

Anyway, this is an informational topic for me, not an issue thing.
 
S

shadyJ

Speaker of the House
Staff member
Thanks for the input, guys.

I do plan to move the center forward a bit so that the baffle is slightly in front of the shelf edge. I don't expect much of an effect, but it can't hurt. I'll probably do this and then do another calibration when the Monolith floorstanders are available (planning to buy them).

Those "before" plots were made by the MultEQ app (Monolith first, Polk CS400i second) and I use a pretty tight mic spacing for the calibrations, so the plots are pretty much on axis with the center.

With the app, if I apply correction to 800 Hz, the Monolith "after" plot shows a flattening of the response in the 200-600 Hz region, so yes, applying correction (XT32) is an option. I usually try to apply minimal correction to the LCR, by limiting the correction range to 350 Hz, but the Monolith center would need correction to about 800 Hz, if I want to flatten the region with dips.

Assuming the dips are from ground bounce, interesting that 2 different models in same location would produce different ground bounce effects and/or other cancellation effects. But, then again, they are different designs: a sealed 3-way vs. a ported 2.5-way.

I do not expect a flat "before" response in-room, although I have seen some better looking app "before" center plots from others. A guy with a KEF Reference center comes to mind.

BTW, the Monolith center sounds great - no complaints. I think is has a bit of an edge on the Polk for vocal clarity, but not a huge difference from my initial impressions.

Anyway, this is an informational topic for me, not an issue thing.
The Monolith speaker will certainly have a dynamic range advantage over the Polk speaker. It will also have a more even sound off axis. A design like the Polk speaker is bound to have a odd off-axis response.
 
A

Adam2434

Audioholic Intern
The Monolith speaker will certainly have a dynamic range advantage over the Polk speaker. It will also have a more even sound off axis. A design like the Polk speaker is bound to have a odd off-axis response.
Just curious - by dynamic range advantage do you mean max volume before compression/distortion because of what was required to meet the THX certification?

Or, do you mean something more inherent to the design of a sealed 3-way (forget THX)?

Of course, the Monolith has a dedicated midrange driver, which would spread the work over more drivers vs. the Polk.
 
S

shadyJ

Speaker of the House
Staff member
Just curious - by dynamic range advantage do you mean max volume before compression/distortion because of what was required to meet the THX certification?
This. The Monolith speakers will be able to remain clean and undistorted at much higher loudness levels than the Polk speakers would manage.
 
A

Adam2434

Audioholic Intern
Not much buzz/love for this Monolith THX line on the interwebs, it seems. I'm a little surprised by that, but maybe it's because they are from Monoprice and not a well-known speaker company. I wonder how well they are doing, in terms of sales numbers. Any other owners out there?

I ordered the center last month when it was on sale for $350, and it is currently on sale again for that price. Still seems like a heck of a center for $350. Not sure I can think of a better center for $350, based on objective performance criteria. Would others tend to agree, or know of better centers for $350?

The non-Atmos floorstanders are supposed to be available in a month. Hopefully, they will run a sale on them when they come out, and I will likely be in for a pair, which is why I bought the center when it was on sale.

I like that the floorstanders are designed to be run sealed (if one chooses), which could provide some additional flexibility/advantage with sub integration.
 
J

JRED 1219

Audioholic
I recently grabbed the front three thx speakers and am very impressed considering how much I paid for them. I guess I got lucky but I was able to get them all up here in Canada for under $1,500 Canadian taxes and shipping included. I am thoroughly impressed with how they sound and they can play louder than I will ever need them to be played.

Even though they are 4ohm, my Denon x3600 has no issue driving them to very loud levels.

Would like the 365ts to lose the upfiring Atmos drivers because I will never use them. I feel like they would sell more without the top firing speakers.
 
everettT

everettT

Audioholic Spartan
Not much buzz/love for this Monolith THX line on the interwebs, it seems. I'm a little surprised by that, but maybe it's because they are from Monoprice and not a well-known speaker company. I wonder how well they are doing, in terms of sales numbers. Any other owners out there?

I ordered the center last month when it was on sale for $350, and it is currently on sale again for that price. Still seems like a heck of a center for $350. Not sure I can think of a better center for $350, based on objective performance criteria. Would others tend to agree, or know of better centers for $350?

The non-Atmos floorstanders are supposed to be available in a month. Hopefully, they will run a sale on them when they come out, and I will likely be in for a pair, which is why I bought the center when it was on sale.

I like that the floorstanders are designed to be run sealed (if one chooses), which could provide some additional flexibility/advantage with sub integration.
If you believe the measurements, there is no problem.
 
J

JRED 1219

Audioholic
I think everyone just focuses on the "bouncy house" Atmos drivers. Really wish they could ditch those so people would stop talking about them when they look at these speakers...
 
Kingnoob

Kingnoob

Audioholic Samurai
The Monolith speaker will certainly have a dynamic range advantage over the Polk speaker. It will also have a more even sound off axis. A design like the Polk speaker is bound to have a odd off-axis response.
How does mixing brands work ? Don’t they have the same tweeters?? Very cool mono-price stuff looks so good .


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