Seeking advice on building 3 identical speakers for Home Theater's front stage

Greetings everyone,

I'll try to mostly use bullets for easier reading.
  • Current setup: Denon X-2700H, Dual Monolith 13inch subwoofers, Monolith THX 365C, Monolith THX 365T's, two small satellite speakers for surrounds.
  • Wants: Upgraded front stage (L,C,R speakers).
  • Usage: both movies and music.
  • Room: dedicated one, 13ft x 13ft, with concrete floors, 1 drywall and 3 walls of cement.
  • Budget: I can go for 1.000euros per speaker give or take (I'm at the Europe market).

Two videos got my attention on Youtube and gave me some ideas but I have no idea what to choose and why.

<--- This one is a 2way speaker with a 15inch Eminence driver and the new Textreme Eminence Compression driver.

<--- And this one is again a 2way speaker inspired by JTR Noesis dual 12's, using SB Audience drivers.

Should I go for a 3-way design? I read that some BMS coaxial compression drivers are epic since you get both the mid and the high frequencies coming from a single unit.

I want something really sensitive as it would be awesome if I could drive my new DIY speakers with my current Denon and not have to buy a new AVR with preamps. SPL is really important to me since I love reference volume levels (my current setup can't do that).
 
diyAudio Member
Joined 2007
How close are the seats to the front speakers?
My own set-up is not that good but when listening to my own at -20 it is plenty loud and if I increase the volume to -10dB I'd be deaf inside an hour.
Perhaps what you need are a couple or three more subwoofers and room treatment
 
13ft x 13ft, with concrete floors, 1 drywall and 3 walls of cement.
That is not a very big room for refrigerator-sized loudspeakers that usually have a large minimum listening distance required for proper integration of LF/HF. And with concrete, there's going to be lots of treble going around (and round), and so lots of treatment needed, as already mentioned above. Also, if you want a front 'stage' you mostly want a baffle wall or in-wall speakers.

Between the choices you've shown, I'd pick the first (smaller) one as opposed to the MTM.

Should I go for a 3-way design? I read that some BMS coaxial compression drivers are epic since you get both the mid and the high frequencies coming from a single unit.
If you can, I think you should, as coaxial drivers solve the integration and spacing problem mentioned above (to some extent).
 
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Will there be a high-pass filter on the speakers?

ex. My HT Receiver has a 100Hz cross-over.

Also what is your height restriction relative to the bottom of your screen?

If by high-pass filter you mean that crossovers, then yes, I always cross my speakers to my subs at around 80-100Hz. If not, sorry for not understanding, I'm not that experienced.

As far as the height restriction, I can have max 3,9ft (for the center speaker). Left and right speakers can be even higher.

How close are the seats to the front speakers?
My own set-up is not that good but when listening to my own at -20 it is plenty loud and if I increase the volume to -10dB I'd be deaf inside an hour.
Perhaps what you need are a couple or three more subwoofers and room treatment

The seats are 10-11ft away from the front speakers.

More room treatment is always on my plans, yes. More subwoofer, even thought I'm a bass head, I feel that those dual Monolith 13's are more than enough for this room and the gain knob is at half setting even. After completing my front stage, I'll set sail for dual 18's subs, maybe full Marty's or something.

As for the volume levels, I agree that -20 is plenty loud, but when it comes to Youtube music or anything else besides UHD disks that have amazing sound, I find myself pushing it at -5dB's and wanting much much more (party animal here).

Ideally, I'd love to have the headroom to turn my speakers to the side, facing a huge window on the left side of the room and throw a garden party.

When one of my daughters was getting married, my current setup couldn't get loud enough for anything outside that room and even when I moved them outside, they weren't strong enough. So, professional theater speakers/PA systems, anything of that nature is my next step.
 
That is not a very big room for refrigerator-sized loudspeakers that usually have a large minimum listening distance required for proper integration of LF/HF. And with concrete, there's going to be lots of treble going around (and round), and so lots of treatment needed, as already mentioned above. Also, if you want a front 'stage' you mostly want a baffle wall or in-wall speakers.

Between the choices you've shown, I'd pick the first (smaller) one as opposed to the MTM.

Should I go for a 3-way design? I read that some BMS coaxial compression drivers are epic since you get both the mid and the high frequencies coming from a single unit.
If you can, I think you should, as coaxial drivers solve the integration and spacing problem mentioned above (to some extent).


It's not a very big room for sure.
The first choice (that you picked), those speakers are 12inches deep, extremely shallow for a 15inch speaker. Thing is, are they going to be better quality, more sensitive and louder than the MTM design on the second choice?

Hmm so I could go for the Eminence 15inch woofer and a coaxial driver from BMS using the same design, correct?
 
As for the volume levels, I agree that -20 is plenty loud, but when it comes to Youtube music or anything else besides UHD disks that have amazing sound, I find myself pushing it at -5dB's and wanting much much more (party animal here).
This is because YouTube has a lower signal strength than Blu-rays.
Currently, YouTube videos normalise their full audio mix (all audio combined) between -12db to -20db.
https://filmstro.com/blog/how-to-se...n all agree,recommend never hitting that high.

You should take an SPL measurement to see what output levels you’re at so you can get an idea of what you want to achieve.
Ideally, I'd love to have the headroom to turn my speakers to the side, facing a huge window on the left side of the room and throw a garden party.
There’s conflicting information going on. Your theater setup sounds like it gets plenty loud for movies, but not loud enough for outdoor parties.

If you want music for a party, leave your theater setup alone, but add room treatments so it sounds better. Buy a pair of JBL Control 30 speakers, mount them outside pointing at the garden party area and power them with your AVR. Unless your guests are a long ways away, you’ll have more sound than you can comfortably talk over.
 
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The first choice (that you picked), those speakers are 12inches deep, extremely shallow for a 15inch speaker. Thing is, are they going to be better quality, more sensitive and louder than the MTM design on the second choice?
Looking at your room (13 ft), shallower would be better, as cabinet volume could be easily met by making the baffle wider. It is generally difficult to predict the sound quality without listening to the speakers in person.
Hmm so I could go for the Eminence 15inch woofer and a coaxial driver from BMS using the same design, correct?
Yes, a 15 incher and a horn (coax if 3-way) is probably the way to go. However, besides Eminence, there are many other brands that perform well (e.g. Faital Pro). You may also consider cloning some commercial studio / cinema speakers, like the Asathor that is popular on this forum.

https://www.diyaudio.com/community/threads/asathor-a-jbl-4367-clone.367215/
 
This is because YouTube has a lower signal strength than Blu-rays.
Currently, YouTube videos normalise their full audio mix (all audio combined) between -12db to -20db.
https://filmstro.com/blog/how-to-set-the-right-audio-levels-for-youtube#:~:text=But we can all agree,recommend never hitting that high.

You should take an SPL measurement to see what output levels you’re at so you can get an idea of what you want to achieve.

There’s conflicting information going on. Your theater setup sounds like it gets plenty loud for movies, but not loud enough for outdoor parties.

If you want music for a party, leave your theater setup alone, but add room treatments so it sounds better. Buy a pair of JBL Control 30 speakers, mount them outside pointing at the garden party area and power them with your AVR. Unless your guests are a long ways away, you’ll have more sound than you can comfortably talk over.

I now see why Youtube's audio mix is lower in volume.

For the SPL measurement that you mentioned, I tried using a phone app but it surely does a bad job when it comes to peaks. Should I go for a Umik-1?

This is a good idea, buying an other pair of speakers for the garden area, but I have bad experience using such speakers. I have a pair of Electrovoice SX100+E and I tried what you suggested. My AVR wasn't properly powering them, even at max volume levels the sound was terrible and it wasn't even loud (I need to mention here that I ran Audyssey before using them).


Looking at your room (13 ft), shallower would be better, as cabinet volume could be easily met by making the baffle wider. It is generally difficult to predict the sound quality without listening to the speakers in person.

Yes, a 15 incher and a horn (coax if 3-way) is probably the way to go. However, besides Eminence, there are many other brands that perform well (e.g. Faital Pro). You may also consider cloning some commercial studio / cinema speakers, like the Asathor that is popular on this forum.

https://www.diyaudio.com/community/threads/asathor-a-jbl-4367-clone.367215/

I couldn't agree more with that, that it's difficult to predict the sound quality without listening to the speakers in person.

I'll definitely take a look at other brands as well. And that project by Asathor look amazing to me! Could you please explain why a 15inch and a horn would be better than an MTM design? I've read some posts that 12inch woofers are much better than 15's, especially if you're crossing them to dedicated subwoofers.



https://www.thomann.de/gr/ev_sx100x...C0XwsYOFzhdszBLh7Vwa1xoCl-sQAvD_BwE#bewertung
 
Ok, final question:

-what is it that you are hoping to achieve that is an “upgrade” over what you already have?

(basically what you already have is more than good enough for your use-case, at least objectively.)

The "upgrade" I'm hoping to achieve is just SPL. I have no complains about sound quality, since my current 3-way THX little Monolith speakers are great. They just won't give me that "oommpphh" I want.

Audioholics review of those Monolith speakers mention that someone could have a house party if they wanted to using these speakers.

Could it be my AVR being unable to fully power my current speakers?
 
Could you please explain why a 15inch and a horn would be better ...?
In general, the 15 incher could cross much lower (say 800Hz) to a slightly larger compression driver like a BMS, rather than above 1kHz, as with the 12 inchers. A 15 incher is also likely to be more efficient and would have lower excursions for the same SPL. Besides, the market for 15 inchers is much bigger than that for 12s, making it easier to find drivers with good parameters.

Could it be my AVR being unable to fully power my current speakers?
Unlikely, since there are many readymade cinema units with dual 15s that maybe easily driven by an AVR (say 50W/ch), at least in a room like yours. It is however very likely that your current speakers themselves are unable to put out the SPLs you expect, at least not efforlessly.
 
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Should I go for a 3-way design?
No. If you are not an experienced builder, stick with a 2-way. And anyway, both cinema and HT were 2-way for decades. Coax could be nice since you are fairly close, but coax crossovers and be tricky to get just right. For your needs and room you should look at the Econowave project, both here and on other forums. It's a 1" horn and woofer 2-way, much like your first choice.
 
Could it be my AVR being unable to fully power my current speakers?
Yes IF you are using the AVR to power all channels and your AVR doesn’t handle the speaker’s load well (that’s the Impedance vs phase angle).

My own AVR has this problem past a certain spl with any type of surround use (Pioneer Elite). ..and I made my speakers fairly efficient with an easy Impedance, and it depends on the surround input for my AVR where most of my use over streaming is OK but a quality B-Ray DVD has a more distinct sp-level for compression.

Try your system ONLY in STEREO (2-channel) with the same cross-over to hear if there is any improvement.

Note: check to see if your AVR has pre-amp OUT for adding an amplifier.

IF it’s not the amplification then an easier path to Pano’s suggestion is:

https://www.diysoundgroup.com/home-theater-speaker-kits/ht-10-kit.html
 
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The "upgrade" I'm hoping to achieve is just SPL. I have no complains about sound quality, since my current 3-way THX little Monolith speakers are great. They just won't give me that "oommpphh" I want.

Could it be my AVR being unable to fully power my current speakers?
I own Peavey's equivalent of the 2 way speakers top video post #1, in a 14'x15' x12' room. I listen from 9' away on my couch, or 33' away eating in my kitchen through the double door opening. I like the setup; distortion is extremely low at the 1/8 watt I typically listen to. I allow peaks of up to 50 w in my music room. However, if I want to throw a party in the yard, the SP2(2004) will put out 500 w each AES (pink noise). I use a 70 w/ch amp indoors, a 260 w/ch amp outdoors.
So yes, I would suggest your party failure was lack of amp, or lack of sensitivity of the speakers. My pair are 98 db 1w1m which is extremely efficient. I can drive myself out of the room with earplugs in at 72 w/ch. The speakers in video 1 could be that efficient, the N314X-8 is 110.5 db 1w1m and the eminence Deltapro15's I have for a project are 101.6 db 1w1m. Peavey does a lot of cabinet tricks to make the SP2(2004) spray evenly over 45 deg off axis (6 db down 54 hz-17.5 khz) with the woofer carrying to 1800 hz. But with a N314X-8 CD rated at 150 W AES you could let the horn carry down to 800 hz and still get 500 w out of the cabinet AES without the difficult wedge shaped construction and 45 deg elastomer folds I see inside my SP2(2004).
Many home theater systems are rated maybe 40 w/ch 4 channels and 100 w sub, but the fine print is the power supply will not put that much out all at once. Maybe yours has that problem. You need 200 w/ch stereo to throw a yard party with 98 db 1w1m speakers, and 400-500 W/ch with less sensitive speakers and a rowdy crowd. Porting the theater signal sources out to a party amp could be a solution for that scenario, even if you use the same speakers inside (1/8-50w/ch) as outside.(10-200 w/ch).
I don't know why you would need all the bass of CD+15" speakers on all 3 front channels. My SP2(2004) go to 54 hz - 3 db, which is great for classical and rock&roll music without a sub. My music room setup is stereo. But 200 hz up response should be adequate for a center channel IMHO. I don't have an opinion about the rear channels in a theater setup, I don't own a home theater amp and am very not impressed by rear channels when I do visit a theater.
BTW a real sub is something like the Eminence Lab12 driver built into the large vented cabinet in the cabinet drawings on the eminence website. You'll need a real electronic crossover to cut below 20 hz 18 db/octave, and those devices from Rane, Nady, Peavey, also merge the bass of 2 channels for the single sub channel, give you a top rolloff frequency of the sub adjustable with a knob or rotary switch, and send the 2 main channels out to the power amp with the sub frequencies aubtracted off, which saves your amp power for what the main corner speakers can actually reproduce. Having more than 1 sub channel is IMHO silly, since the wavelength is longer than your room and the ear cannot locate those frequencies indoors.
Happy shopping and later building.
 
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Seeking advice on building 3 identical speakers ... As far as the height restriction, I can have max 3,9ft (for the center speaker). Left and right speakers can be even higher.
The above points seem to be contradictory. So what is your mechanism for video delivery ? Identical LCR typically has a good front stage but often works better with projection systems as opposed to TVs, due to placement issues.

I want something really sensitive as it would be awesome if I could drive my new DIY speakers with my current Denon and not have to buy a new AVR with preamps. SPL is really important to me since I love reference volume levels (my current setup can't do that).

I think your current speakers are 90dB/W/m, and that you'd like to listen to 85dB (avg) per screen channel. If the LP is assumed to be 13 feet (4 metres), you would need an average power of about 5W/ch, which an AVR can easily provide. Now, considering a peak SPL of 105dB per channel (as per cinema standards), the power would be 500W (peak), which the AVR may or may not be able to provide, depending on the capabilities of its power section.

Now, if the speakers were simply 97dB/W/m, the power for 105dB peak / ch would be down to 100W (peak)/ch, which most AVRs can easily supply. So, I would agree with the idea of changing speakers vs changing amplification.

Nevertheless, it is important to ask what model and what average/peak power per channel your Denon AVR is. And, are you regular 5.1 or some other advanced setup like Atmos?

EDIT: Please note that the above calculations do not consider the power compression phenomenon that is likely to be much higher for the smaller HiFi driver with a small voice coil, when compared to that in a professional high efficiency one.
 
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