Yes, but I was confused if you may have been talking about folks sometimes adding a large non-polar elec. cap before the xo. Sorry, I'm used to thinking in terms of designing speakers not amplifiers.
Which reported data are you talking about? The (not) parallel diode?
What are you getting at with the drivers fs higher than I think? are you saying this may be the cause of the early roll-off? It's ported so the port should still be extending the frequency some unless it was way higher than expected, but like I said, it isn't
Which reported data are you talking about? The (not) parallel diode?
What are you getting at with the drivers fs higher than I think? are you saying this may be the cause of the early roll-off? It's ported so the port should still be extending the frequency some unless it was way higher than expected, but like I said, it isn't
Fc -3dB is controlled by Q and box tuning, so yes. that's why decreasing the blocking cap can give more bass.
I was just asking if you can confirm which is which. yer throwing lots of numbers around now , just asking for the source.
the port output is acoustic data with microphones, the models are just graphically added to the woofer output.
its the same function here, in addition to blocking the DC.
sometimes people confuse their modeling and real data.
I was just asking if you can confirm which is which. yer throwing lots of numbers around now , just asking for the source.
the port output is acoustic data with microphones, the models are just graphically added to the woofer output.
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Got it, got it, got it
I'll try a different cap and see what happens. If it is indeed creating a corner frequency that high then I probably want to increase the value, lowering fc and q because I already dialed in a bit of a high box q to begin with. I'll have to see it the driver handles the lower frequencies or not
I model with advertised specs just to check feasibility, but when it comes to manufacture's specs I subscribe to the measure and then believe it when I see it camp.
I'll try a different cap and see what happens. If it is indeed creating a corner frequency that high then I probably want to increase the value, lowering fc and q because I already dialed in a bit of a high box q to begin with. I'll have to see it the driver handles the lower frequencies or not
I model with advertised specs just to check feasibility, but when it comes to manufacture's specs I subscribe to the measure and then believe it when I see it camp.
I measured the impedance free air to get it's TS then also measured inbox to verify the port tuning. The phase crosses 0 at 74Hz I believe. This is before the xo was implemented. The added resistance and inductance will change the q and possibly tuning some. I also measured the frequency response of the woofer near field with the port plugged and the port near field and every thing looks OK, if not rolling off a bit sooner that expected
I will say that if you have good data then I find most of the box modeling programs to typically be very accurate except sometimes on the calculated port length. You do really need to model with the xo accounted for though which I think a lot of people don't do.
Mostly I'll use Unibox for it's ease of use and accuracy.
Mostly I'll use Unibox for it's ease of use and accuracy.
that's smart checking the closed box model 1st to confirm
the port output is then added the new woofer output (unblocked port) to extend the LF response.
unibox handles both of these if you check it close
the port output is then added the new woofer output (unblocked port) to extend the LF response.
yup inductor Rdc and the drivers Le all need to be accounted for in the Xo
unibox handles both of these if you check it close
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Yeah, it's hard enough knowing what's real and what's room that low. Then add a port on the back of the box and it's really just guessing when looking at the measurement. I don't like to tune a speaker or adjust eq on the low end based on inroom measurements, but if you measure it sealed and nearfield then you can do a sanity check with the model and also extrapolate what the speakers true response (sans room gain) is likely to be.
Yes, without taking these into account the tendency is to tune too low which I notice some people doing. This will usually result in reduced power handling and reduced bass actually.
I also notice people tuning for the lowest f3, without fail, but that's a whole other discussion.
That's what I use for my subs; multiple sealed 15's in as big a box as was feasible (because I went with drivers that want to in refrigerator size boxes, but I settled on 120 liters). In my opinion the lower q response of sealed matches a typical room's inverse gain better than a super extended ported box, so yes, I think it sounds better, but others think differently and they have their reasons too
It just makes a lot of sense, easier to build, design, lots of room for error. Lower group delay and often similar output to to a woofer a size down in a ported box in about the same size box.
One more question about the amp and caps before I go to bed. The input side has a 100uF 16v, should this be adjusted at all. And also do you know of a way to measure the amplifiers Frequency response without specialized equipment? As in not measuring a speaker's response when connected to it, but instead the direct output? I can't think of anything. Maybe some kind of a loop back like you would measure a computers soundcard response, but I doubt my computers input could handle a high level signal
And a lot to learn. That and the electronics feels like when I was trying to learn speaker design, only maybe more complicated
The amp has an adjustable gain screw. Would this work in place of the attenuator and if so are you saying that I would basically turn it down to nearly 0?
If not is a fixed l pad ok? I think I also have an adjustable 4 ohm l pad or two floating around
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