Hello Folks,
I've decided to try my hand at making speaker systems and I'm looking for a critique and some guidance moving forward. I have decided I would like to make an MTM speaker system with a 2 channel, bluetooth amplifier as my first project. My goal is to learn the fundamentals through practical application using relatively cheap hardware for this process. I have been pouring through a lot of online resources and find myself in a place of wanting to get my hands dirty. I would appreciate hearing any thoughts or advice on my following plans:
Tweeter: Dayton DCF28F (8 ohm)
Woofer x 2: Dayton DA135 (8 ohm) - I think I made a mistake here (because I already ordered the speakers). The woofers will be installed in parallel which means they will appear to the amplifier as a 4 ohm load. Should I purchase a 4 ohm tweeter or can I use a power dissipating resistor in parallel with the tweeter to bring its load down as well?
Crossover: I need some advice here. The usable frequency for the tweeter is between 1.3 KHz and 20 KHz. The usable frequency for the woofer is 50 Hz and 15 KHz. Would I select the lower end of the tweeter frequency as my crossover point in designing the circuit?
Cabinet: I've been told that cabinets need to be over built so I plan on using 3/4" MDF and venting it. The recommended volume for a single woofer is .43 cubic ft so I will double that to accommodate the two woofers.
Amplifier: I would appreciate some recommendations. I would like to use a single board which can be installed in the cabinet so the system is self contained.
Looking forward to your thoughts and critiques!
I've decided to try my hand at making speaker systems and I'm looking for a critique and some guidance moving forward. I have decided I would like to make an MTM speaker system with a 2 channel, bluetooth amplifier as my first project. My goal is to learn the fundamentals through practical application using relatively cheap hardware for this process. I have been pouring through a lot of online resources and find myself in a place of wanting to get my hands dirty. I would appreciate hearing any thoughts or advice on my following plans:
Tweeter: Dayton DCF28F (8 ohm)
Woofer x 2: Dayton DA135 (8 ohm) - I think I made a mistake here (because I already ordered the speakers). The woofers will be installed in parallel which means they will appear to the amplifier as a 4 ohm load. Should I purchase a 4 ohm tweeter or can I use a power dissipating resistor in parallel with the tweeter to bring its load down as well?
Crossover: I need some advice here. The usable frequency for the tweeter is between 1.3 KHz and 20 KHz. The usable frequency for the woofer is 50 Hz and 15 KHz. Would I select the lower end of the tweeter frequency as my crossover point in designing the circuit?
Cabinet: I've been told that cabinets need to be over built so I plan on using 3/4" MDF and venting it. The recommended volume for a single woofer is .43 cubic ft so I will double that to accommodate the two woofers.
Amplifier: I would appreciate some recommendations. I would like to use a single board which can be installed in the cabinet so the system is self contained.
Looking forward to your thoughts and critiques!
the difference in imedance should make ittle difference.
MDF is really not the best material to build loudspeakers out of.
Do not trust what PE sys about the alignment without actually doing the modeling work. The highish Q and Fs are someties tricky to get a decent alignment…
I have a pair of the 6.5” version of these drivers, unused, supposed to be good. I expect these will benefit from a coat of modPodge to help deal with their significant ringing above 2k.
XO needs to be designed specificlly for the drivers and the box. You might be able to use the first resonance (a dip) as part of the XO, i would not really like to try using them above that. The tweeter might have issues reaching that low. The woofer does not have a nice smooth rool-off is often not easy to work with (modPodge will help that)The numbers PE gives are sort of ridlculous.
You have the drivers on the way so that is what you have to work with. Not the ones i would have choosen.
dave
MDF is really not the best material to build loudspeakers out of.
Do not trust what PE sys about the alignment without actually doing the modeling work. The highish Q and Fs are someties tricky to get a decent alignment…
I have a pair of the 6.5” version of these drivers, unused, supposed to be good. I expect these will benefit from a coat of modPodge to help deal with their significant ringing above 2k.
XO needs to be designed specificlly for the drivers and the box. You might be able to use the first resonance (a dip) as part of the XO, i would not really like to try using them above that. The tweeter might have issues reaching that low. The woofer does not have a nice smooth rool-off is often not easy to work with (modPodge will help that)The numbers PE gives are sort of ridlculous.
You have the drivers on the way so that is what you have to work with. Not the ones i would have choosen.
dave
Thanks for chiming in, Dave. I appreciate your comments but have to admit the most of what you spoke of went over my head. As I said, I'm just getting started and this process is certainly more complicated than just screwing drivers into a box.
MDF is extremely dense. What makes for better cabinet enclosures? Hardwood stocks?
If you don't mind...what does this mean: "Do not trust what PE sys about the alignment without actually doing the modeling work. The highish Q and Fs are someties tricky to get a decent alignment… "
And what is this about modPog?
I appreciate what you said about not the speakers you would have chosen. My goal is to learn. And I would rather make mistakes with lower end products. If I'm careful, I'm hopeful I can make relatively cheap drivers sound decent enough for a table top MTM system.
Thanks again, Dave.
MDF is extremely dense. What makes for better cabinet enclosures? Hardwood stocks?
If you don't mind...what does this mean: "Do not trust what PE sys about the alignment without actually doing the modeling work. The highish Q and Fs are someties tricky to get a decent alignment… "
And what is this about modPog?
I appreciate what you said about not the speakers you would have chosen. My goal is to learn. And I would rather make mistakes with lower end products. If I'm careful, I'm hopeful I can make relatively cheap drivers sound decent enough for a table top MTM system.
Thanks again, Dave.
I have used some thin strips of a weatherstripping foam (self adhesive) to help tame the cone edge(?) ringing on a similar Klipsch driver. The (8), 3/16” X 3/16” X 1/2” strips were placed neither radially (like spokes), or concentric, but at angles, equally spaced around the perimeter of the cone.
A fuzzy, non-reflective covering on the baffles helped a bit too, at least in my situation.
I don’t have experience with those particular drivers however, so am no help for crossover recommendations…
A fuzzy, non-reflective covering on the baffles helped a bit too, at least in my situation.
I don’t have experience with those particular drivers however, so am no help for crossover recommendations…
On thing I'd recommend is the use of an amplifier with DSP, if you can get one.
The 4-channel Zoudio and Wodom (with the ADAU1701) can output high and low frequency channels setup how you wish, to each speaker's woofer and tweeter. The cost of these amplifiers I believe is competitive with the cost of passive crossover components.
What it allows you to do is easily experiment with - it's just a software value change - various frequency choices to cross at. This would be hard to do with a separate hardware build for each frequency you'd like to try. Once found to your liking, then you can build the hardware component crossover - or "set it and forget it" if you like the sound of the class D amplification.
The 4-channel Zoudio and Wodom (with the ADAU1701) can output high and low frequency channels setup how you wish, to each speaker's woofer and tweeter. The cost of these amplifiers I believe is competitive with the cost of passive crossover components.
What it allows you to do is easily experiment with - it's just a software value change - various frequency choices to cross at. This would be hard to do with a separate hardware build for each frequency you'd like to try. Once found to your liking, then you can build the hardware component crossover - or "set it and forget it" if you like the sound of the class D amplification.
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Dense is not an asset unless it brings considerablly greater stiffness. The usual goto is quality plywood. Stranded bamboo ply one of the best (at a price). Some solids make for good boxes but you really have to know what you are doing.
They are giving a single possibility when there is really a broad range of possibilities depending on what you are looking for.
Sort of a mistruth by withhiolding information.
Speaker Tweeks -- Puzzlecoat & Ductseal
Learning and play ar eboth valid.
dave