Hello all, I need some help determining a design for a center speaker for movie and tv use. I currently have the Polk s35 as a center which I think is a WMMTMMW array, the bass presence is non existence, voices are difficult to hear, and I'm not to happy with its dispersion.
My L and R are the Polk es50. I understand for 5.1 all the speakers should be the same, financial constraints and space prevent me from buying another es50.
The amp used is a Yamaha v477 set at 8 ohms
Room size is large and open
My main goals are:
I have:
Thank you for your time,
Please don't spend too much of your time, again I'm only looking for guidance, I don't have the means to measure my design or anything like that yet.
My L and R are the Polk es50. I understand for 5.1 all the speakers should be the same, financial constraints and space prevent me from buying another es50.
The amp used is a Yamaha v477 set at 8 ohms
Room size is large and open
My main goals are:
- Create a center that has a better overall presences than the s35
- Increase dispersion
- limit spending
I have:
- two 4 ohm 8 inch woofers,
- two 4 ohm 5 inch mids
- two 6 ohm tweeters.
- an inexpensive 3 way crossover
- Access to woodworking materials and tools
Thank you for your time,
Please don't spend too much of your time, again I'm only looking for guidance, I don't have the means to measure my design or anything like that yet.
Sideways MTMs do not work, this one is going to be a disaster.
The XO would need to be specific to the drivers used. And if you use them only 1 mid + 1 tweeter.
A centre channel does not really need much below 80 Hz.
dave
Good news!….
First….matching front and center is a myth…..always has been….
Second…..as Dave pointed out, speakers in a horizontal configuration are worst case…..dispersion is narrowed dramatically and the more drivers, the worse the effect due to interactions from each drivers wavefront….known as comb filtering
……there’s no surprise your center channel sounds aweful
Easy and inexpensive solution….no build required…..a single KEF Q150 coax speaker on its side. The driver is round and centered so this really doesn’t matter….it will just help to fit under your screen as it’s smaller across than it is tall.
Done, problem solved and you won’t be able to build something for less that will outperform this solution.
If you use a subwoofer, the KEF Q150 comes with a foam port plug…..plug it up and cross to your sub at 80hz or so.
Enjoy!
First….matching front and center is a myth…..always has been….
Second…..as Dave pointed out, speakers in a horizontal configuration are worst case…..dispersion is narrowed dramatically and the more drivers, the worse the effect due to interactions from each drivers wavefront….known as comb filtering
……there’s no surprise your center channel sounds aweful
Easy and inexpensive solution….no build required…..a single KEF Q150 coax speaker on its side. The driver is round and centered so this really doesn’t matter….it will just help to fit under your screen as it’s smaller across than it is tall.
Done, problem solved and you won’t be able to build something for less that will outperform this solution.
If you use a subwoofer, the KEF Q150 comes with a foam port plug…..plug it up and cross to your sub at 80hz or so.
Enjoy!
But if the centre is voiced to match L+R you are way firther ahead.
Or a good FR.
dave
What are the drivers you have?
You won’t find a decent coax that cheap, but this FR is close (and really a siuperb driver, especially when price takeninto consideration.
https://www.madisoundspeakerstore.com/approx-6-fullrange/markaudio-chn110-silver-6.75-full-range/
dave
If you can stretch an extra $20, there's this one
SB Acoustics SB16PFCR25-4
https://www.madisoundspeakerstore.c...cr25-4-coax-6-paper-cone-coaxial-4-ohm-round/
They have 4 and 5 inch versions also, but they're not much cheaper.
They also provide basic crossover designs for use with them: https://www.madisoundspeakerstore.com/pdf/SBAcoustic_PFC_Coaxial_Crossover_Designs.pdf
As others have said, from a function standpoint, using one tweeter above one 5 inch mid is a good approach for that element if you want to use the drivers you have. If you want to add 8 inch woofers to the outside of the central group, you can likely get away with that with a low enough cross point. Unfortunately, the crossover you have isn't really suitable for that.
These are the drivers, they were taken out of a damaged speaker and don't have much in terms of identification on them
- two 4 ohm 8 inch woofers,
- two 4 ohm 5 inch mids
- two 6 ohm tweeters.
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Please ignore the above reference for full range drivers as these suggestions are terrible......full range drivers have worse off axis performance than your Polk and unless these folks can show you their own third party off axis measurements to 45 degrees, disregard.
Would it be possible to add a coil in between the woofer and the crossover? It seems obvious, I just don't want to blow anything up.
have fun!....without either accurate response graphs to model or measuring equipment, the likely hood of success is around the same as a scratch off lottery ticket.
Not looking to discourage or disparage.....complete transparency.......
You can find demo Q150's or used for around $100
You would need to adjust both the midrange high-pass and the woofer low-pass. That would wind up being 4 components if the crossover is 12 dB/octave. Their schematic is a little weird, so I'm not sure what's going on with the midrange circuit in reality.
I just use a pair of coaxial speakers for L & R. No center. But, if you want a multi-way center with wide dispersion, a vertical TM in the middle and woofers to the outside like this would work.
Obviously 100% dead wrong.
Matched speakers makes the smoothest, most beliveable transition. Unmatched speakers obviously does not.
🎺🙂🎸
Yes he his; my main listening position is approx 12ft from front row, less than 5dg off axis from the centre channel driver, and maybe 20dg from the L&R mains (also 10.3s). In well over 6yrs of continuous daily use, I’ve changed receivers and upgraded amps twice, but have no complaints as to the speakers’ performance.
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I completely understand. Its more of a learning experience. I build with hopes that sound will come out of it and I will slightly increase my knowledge and wood working skills.
The term 'centre speaker' refers to a category of wider than taller speakers that was 'invented' by the home theatre in a box (HTiB) manufacturers. The scientifically best centre speaker is always similar to the LR fronts.