Well, speakers... A bunch of drivers on a board is more like it.
And for what it is, I cannot believe how great they sound! (My reference is a set of Polk monitor 60's)
These have a dayton PA310-8 for a woofer, a faital 6fe200-8 for mids, and a dayton pt2c-8 for a tweeter. I guess the way I made the rear it sorta acts like a U baffle.
They are biamped with a minidsp splitting between the woofer and the mid/tweeter, the tweeter has a simple highpass on it, and the mid runs freely up top. Its all driven by "vintage" NAD amps.
I have no measuring equipment beside an app on my phone. If that is to be believed, I'm getting down to about 50Hz with reasonable authority. I only get there because of some massive equalization in DSP, plus tone adjusts on the preamp.
Id like to get some more bass, while reducing the equalization a bit. The plan right now is to build a push pull H frame with two PA310's (I know they're not ideal for OB), and run minidsp's on both sides to make a completely active setup, and even add a few sealed subs just to fill in low, mostly for effects.
In any case, I'm stoked!I'm just blown away by how much better they sound than anything I've ever had. almost a sur(au)real experience!
I'm sure many improvements are possible by correcting errors I made. I'm just really a novice here.
And for what it is, I cannot believe how great they sound! (My reference is a set of Polk monitor 60's)
These have a dayton PA310-8 for a woofer, a faital 6fe200-8 for mids, and a dayton pt2c-8 for a tweeter. I guess the way I made the rear it sorta acts like a U baffle.
They are biamped with a minidsp splitting between the woofer and the mid/tweeter, the tweeter has a simple highpass on it, and the mid runs freely up top. Its all driven by "vintage" NAD amps.
I have no measuring equipment beside an app on my phone. If that is to be believed, I'm getting down to about 50Hz with reasonable authority. I only get there because of some massive equalization in DSP, plus tone adjusts on the preamp.
Id like to get some more bass, while reducing the equalization a bit. The plan right now is to build a push pull H frame with two PA310's (I know they're not ideal for OB), and run minidsp's on both sides to make a completely active setup, and even add a few sealed subs just to fill in low, mostly for effects.
In any case, I'm stoked!I'm just blown away by how much better they sound than anything I've ever had. almost a sur(au)real experience!
I'm sure many improvements are possible by correcting errors I made. I'm just really a novice here.
Those choices look like very good bang for the buck.
Which app?
A Dayton iMM-6 would only be a few $ more, and give slightly more reliable measurements than the in-built mic.
To keep complexity down, I think staying with the current hybrid - keeping the passive crossover between mid & tweeter - is fine, assuming the drivers are nice and happy with low order slopes.
Your plan for improvements seems good to me. Some simple, free things you could try:
- break the symmetry of the 'U'
- partially 'shade' the tweeter with felt or foam to make it more like a point source (if you want broader dispersion)
- chamfer the mid cutout
I'm using "spectroid". Seems to work fine.
I know that mike is pretty cheap, but is it really worth it? I was under the impression that there were some inherent problems with the jack interface that made USB a much better choice. Anyhoo, I think in the future I'll splurge for a umik or partsexpress's counterpart.
What do you mean with "break the symmetry"? Have one leg deeper than the other? Would this also apply to an H frame?
I've not noticed any horizontal problems with the tweeter, but I have noticed that there is a definite plane in the vertical.
Chamfer the rear of the baffle for the mid? I could take a little off, but the're countersunk, there's not a lot of meat left...
Thanks for the suggestions
Your design is not bad at all - it has some characteristics of good OB design:
Baffle not much larger than drivers
Baffle sitting on floor with woofer near floor
Short wings adjacent to woofer
Midrange near top edge of baffle
This can produce an off axis response that is similar to the on axis response. This makes the in-room response much like the direct response, and simple measurement tools like your mic+phone can suffice for quick and dirty frequency response measurements with reasonable accuracy.
Do you have a way to determine when your woofer input (output of the DSP) is clipping? I found this to be a big problem in some miniDSP based OB systems that I have implemented in the past. It helps if the amp input sensitivity is lower, e.g. 0.7V, and I suspect your amp is one of those.
Baffle not much larger than drivers
Baffle sitting on floor with woofer near floor
Short wings adjacent to woofer
Midrange near top edge of baffle
This can produce an off axis response that is similar to the on axis response. This makes the in-room response much like the direct response, and simple measurement tools like your mic+phone can suffice for quick and dirty frequency response measurements with reasonable accuracy.
Do you have a way to determine when your woofer input (output of the DSP) is clipping? I found this to be a big problem in some miniDSP based OB systems that I have implemented in the past. It helps if the amp input sensitivity is lower, e.g. 0.7V, and I suspect your amp is one of those.
I'm glad you are enjoying the sound. Rather than relying on the app, how does the bass sound to your ears? What do you mean by massive EQ? Where is your listening position? This will have a large effect on the bass
Thanks for making me look at this. I have a low shelf before the crossover section, and then on top of that some low EQ through biquads in the crossover itself. putting those two together, and I'm clipping for sure, but it's not been audible.
As far as I know the only inherent problem is the layout - you will get HF reflections off the phone edge and Y-shaped thingo.
Generally you're right - for almost everything, a USB mic is better, particularly for screen dumps and doing before and after comparisons.
The phone mic (and the app I've used, Audio Tool) only shines for quick checks and averaging: you can play noise, move the mic in a small circle and get the average over a small area. This avoids the problem of static position tests, where a small change in mic position can produce a large variance in measured response.
Getting an average takes 5 seconds with iMM-6 and Audio Tool, or a few minutes with a USB mic and REW (where you have to take many spot measurements and then average them, and then delete all the excess measurements).
That, or move one leg to make their spacing from the woofer asymmetric. Or both. Usually perfect symmetry is not ideal: placing a driver dead centre on a symmetrical enclosure or baffle is not quite as good as placement slightly off-centre.
Yea, ditto with the similarly sized Dayton AMT. Probably similar with all planar types of these dimensions. Options include using them in arrays, adding 'abmience' (indirect sound) tweeter(s), other tweaks ...or just accepting that it is what it is.
all good points Charlie
the only thing I would do differently is put a tweeter right above the midrange driver
The next iteration will have one more PA310 driver, a miniDSP, and 4 channels of amplification through two TDA7498E boards per speaker. Connection through bluetooth.
I've been playing this for a while, and at the lowest gain setting, the fan on the amp never comes on (every day listening volume). Annoyingly, the fan on the power supply runs all the time, and i need to fix that.
The smps is a 600w, 36V unit, each speaker will get one.
These speakers were never meant to be extremely HIFI, but the sound is actually very good. I can hear some hiss with my ear at the tweeter at max volume without a source. No way that would contribute to anything I can hear with a source connected.
That looks great! Reminds me of me twenty years ago. You're hooked now for sure!
Just my two cents, but rather than adding another woofer, I'd do a separate subwoofer and use the OB only above 100 Hz. That will greatly increase your dynamic range and reduce the need for massive eq on the woofer which is meaning huge excursion right now. Depending on your music preferences, it can be impractical to get adequate output in the deep bass from OB. personally I need 110db at 1 meter at 35hz. Great job and thanks for sharing. Craig
Just my two cents, but rather than adding another woofer, I'd do a separate subwoofer and use the OB only above 100 Hz. That will greatly increase your dynamic range and reduce the need for massive eq on the woofer which is meaning huge excursion right now. Depending on your music preferences, it can be impractical to get adequate output in the deep bass from OB. personally I need 110db at 1 meter at 35hz. Great job and thanks for sharing. Craig
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