Sorry.
If you want to roll-your-own frequency chip, you'll need a 14-pin DIP... It's been a while, but I think it's usually called a header. It's just a little plug with terminals for you to solder in whatever components you wish.
Mouser and Digi-Key had them. If you're near AudioLab in ATL, it may be more convenient to get it there if they have them.
Use the formula to calculate the resistor value needed for the desired frequency. Look that up on infinia's link (or web search) to see if it a "standard resistor value". If it isn't, and isn't close enough to be replaced by a standard value, then you can series/parallel to get what you need.
Or just buy the closest chip from AC if it's close enough.
If you're curious about the 90Hz chip, remove it and read resistance with a DMM.
infinia?
If you want to roll-your-own frequency chip, you'll need a 14-pin DIP... It's been a while, but I think it's usually called a header. It's just a little plug with terminals for you to solder in whatever components you wish.
Mouser and Digi-Key had them. If you're near AudioLab in ATL, it may be more convenient to get it there if they have them.
Use the formula to calculate the resistor value needed for the desired frequency. Look that up on infinia's link (or web search) to see if it a "standard resistor value". If it isn't, and isn't close enough to be replaced by a standard value, then you can series/parallel to get what you need.
Or just buy the closest chip from AC if it's close enough.
If you're curious about the 90Hz chip, remove it and read resistance with a DMM.
infinia?
mitchyz250f said:
Hi Mitch
Can we move the port frequency down?
I think you could play with your box tuning to optimize it for a lower Xover freq. (110-150 Hz). Try a smaller box with Fb just below Fr. The box response will roll-off a bit slower, better group delay, and the port unloads a little lower? This will result in tighter mid bass, sacrificing F-3dB. Compare your results to an EBS design and the responses should meet arount F-8 dB or so.
See if you can tune the box to move the port unloading down in freq. Maybe EBS is best, I don't know without playing with a Box program.
Now you can determine the Xover filter frequency.
Once you have the box alignment you want, print the two charts like I posted. Find the frequency where the port unloads (Fpu). (Xmax vs Freq chart). Then on the other chart, use that freq (Fpu) and a slope of 18 dB/oct to find the corner freq. based on how much attenuation you want at Fpu.
Once you build it, you can adjust the port length by measuring the impedance. Find a Zmin between the 2 peaks, Zmin is the Fb.
Edit> Seems like alot of work fine tuning, i.e. getting the lowest midbass freq. at 6 dB louder. Is the difference from halfway on the the volume knob to full tilt.
I have been trying to use Unibox. I am modifying the cabinet tuning and size but I m not sure of the objectives. I have a few questions;
1) How do I use the electronic crossover feature? Can't seem to get it too work.
2) Infinia wrote 'We are talking about hopefully getting 6-10 dB of out band rejection by fine tuning your port and box alignment to the HP filter corner.' At what frequency am I supposed to be 6-10 db down? Is it the point where the cone excursion exceeds the xmax? In your plot I think it was 80 db or so.
3) Infinia: What are my calculated measures that my midbass tightening up my midbass (transients)? Or conversely what are the measures that my midbass is getting looser? I read this in another tread by Chris8 'Transient decay response is directly related to frequency response. The smoother, more gradual roll off will always have better transient 'response' than a steeper roll off. How much? Well, if you want specific software simulation to view step response/tone burst simulation....you can use the Unibox excel spreadsheet from the frd consortium'.
I one point I was trying to get a similar response curve as a 2204. I thought that by modeling the response of a good performing midbass that that would be a good start.
These are the question I have for now.
1) How do I use the electronic crossover feature? Can't seem to get it too work.
2) Infinia wrote 'We are talking about hopefully getting 6-10 dB of out band rejection by fine tuning your port and box alignment to the HP filter corner.' At what frequency am I supposed to be 6-10 db down? Is it the point where the cone excursion exceeds the xmax? In your plot I think it was 80 db or so.
3) Infinia: What are my calculated measures that my midbass tightening up my midbass (transients)? Or conversely what are the measures that my midbass is getting looser? I read this in another tread by Chris8 'Transient decay response is directly related to frequency response. The smoother, more gradual roll off will always have better transient 'response' than a steeper roll off. How much? Well, if you want specific software simulation to view step response/tone burst simulation....you can use the Unibox excel spreadsheet from the frd consortium'.
I one point I was trying to get a similar response curve as a 2204. I thought that by modeling the response of a good performing midbass that that would be a good start.
These are the question I have for now.
If there is a real problem with a mismatch between midbass and midrange I will change the midranges out for something else. I have waited a long time to 'play' with something like these JBL 2123's in my car so for ight now all my energy is going into getting the best sound I can from the MB's.
mitchyz250f said:
Unibox recalc's using T/S so is more accurate at Re(min). I think JBL measures theirs (max) at a higher freq. and converts.
See attached image>> calculate the corner freq to get -10dB at Fpu
Using the plot for the old alignment, Fpu at clear circle.
draw line 18dB/oct from (Fpu-10dB) read corner freq at black circle.
Use Xover set at 120Hz to get 10dB down at 80Hz
edit> Transient will be based on total response of HPF plus driver in box. So for this case I think the HPF dominates and will determine the transient response. ( ie 3rd order cheb. at 120Hz)
Attachments
Lpad's around -8-10 dB at the amp outputs. Otherwise if just relying on a lower input levels, it will increase your noise floor by the amount of atten.
Once you get things kinda settled, you may want to consider building your own. The Orion's phantom power makes is an easier task.
I remember the original 2XS as the first crossover I'd seen to use chips. Others were switch programmable or variable with pots. Much easier to adjust and compare settings.
After researching filter design, AC's reasoning was obvious. Switches have limited settings, and accurate pots aren't practical. Especially when you consider the need for a 4-gang pot to do a single stereo filter.
Anyway, I wait anxiously to hear about your results. I've been considering a similar setup and 3" mids are hard to beat with regards to mounting opportunities and range of operation.
Of course the downside is low sensitivity, limited output at lower frequencies, and limited power handling.
Todays 4" drivers in general have a significant advantage in cone area, excursion, and low end extension. But most are just large enough to prevent them in many locations...
infinia:
I seem to remember the 2XS using a butterworth. But that's a good point.
Gain for the amps driving the speakeers in question should be within a couple dB at most. The midrange amp is 100W/ch and the midbass amp is 80W/ch ( both 4 ohm ratings)
Input sensitivity controls on the amps should have a range of 10dB or so. And fortunateLy, the S/N ratio won't be as important on the midbass amp.
idea's for... mid sensitivity increase
Hi
If you double up on 3" mids side by side, you gain 3 dB for doubling the radiating surfaces.
In addition, you also you gain another 3dB due to halving driver Z using a voltage feedback amplifier.
you also might consider these for mids> see http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-812&ctab=2#Tabs
thus 86 dB/W +6 dB or there abouts at 3.3 ohms
90-92 dB s/b close to tweeter and closes the sens. gap on the midbass.
Hi
If you double up on 3" mids side by side, you gain 3 dB for doubling the radiating surfaces.
In addition, you also you gain another 3dB due to halving driver Z using a voltage feedback amplifier.
you also might consider these for mids> see http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-812&ctab=2#Tabs
thus 86 dB/W +6 dB or there abouts at 3.3 ohms
90-92 dB s/b close to tweeter and closes the sens. gap on the midbass.
Here's a smaller tweeter that you could consider for a MTM pillar mount, using the above 3" mids. Cost under $8 ea.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-030
Good sounding when used in a large floor standing design
see example> http://www.zaphaudio.com/ZDT3.5.html
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=275-030
Good sounding when used in a large floor standing design
see example> http://www.zaphaudio.com/ZDT3.5.html
Why not just go for a 2" dome midranges; those are pretty common in the 90 - 92 db range. But I would have to crossover pretty high, like 5-600 Hz.
Right now I have to stay focused on the midbasses. I just took the baffle out of the quarter panel and removed the IDQ8's. There is a lot of work to be done to make those into ported cabinets. My current thinking is to tune a .35-.4 cu ft box to 70-80 Hz range. Please comment on the box and tuning.
I am going to move my crossover around a bit and let the radio handle the split between the sub and midbass. That will allow me to use a 24 db crossover at 100 or 125 Hz on the MB. It will also allow me to us TA on the sub and MB. I will use the 2XS to separate the mids and MB. I just ordered Chips from 200 to 480.
Ok regarding this;
'So for this case I think the HPF dominates and will determine the transient response. Use Voltage sens. for all drivers and noting the gain for each of power amps. Keeping the V level high at PA inputs preserves the S/N ratio. ( ie 3rd order cheb. at 120Hz).'
OK, so a 24 db crossover should help this. I will start with only 40 watts at 8 ohms on the MB's so I don't really have to worry about this or do I? I plan to have more power later, but right now I am concentrating on building the right MB box.
The woofer I am using has a Le of 1.3. How do you think it will handle higher crossovers at 100 and 125 Hz regarding transient behavior? I will be able to cross the sub over at 36 db if needed.
Right now I have to stay focused on the midbasses. I just took the baffle out of the quarter panel and removed the IDQ8's. There is a lot of work to be done to make those into ported cabinets. My current thinking is to tune a .35-.4 cu ft box to 70-80 Hz range. Please comment on the box and tuning.
I am going to move my crossover around a bit and let the radio handle the split between the sub and midbass. That will allow me to use a 24 db crossover at 100 or 125 Hz on the MB. It will also allow me to us TA on the sub and MB. I will use the 2XS to separate the mids and MB. I just ordered Chips from 200 to 480.
Ok regarding this;
'So for this case I think the HPF dominates and will determine the transient response. Use Voltage sens. for all drivers and noting the gain for each of power amps. Keeping the V level high at PA inputs preserves the S/N ratio. ( ie 3rd order cheb. at 120Hz).'
OK, so a 24 db crossover should help this. I will start with only 40 watts at 8 ohms on the MB's so I don't really have to worry about this or do I? I plan to have more power later, but right now I am concentrating on building the right MB box.
The woofer I am using has a Le of 1.3. How do you think it will handle higher crossovers at 100 and 125 Hz regarding transient behavior? I will be able to cross the sub over at 36 db if needed.
Mid Domes
I like mid domes alot, but they are difficult to get right and they never go as low as you want them to. The 3" cones should be easier to work, wider bandwidth, cheaper, and mechanically smaller than 2" domes. Tiny MTM's would be very cool IMO. It's got me thinking of my own project. An MMTMM using those drivers I suggested above.
Midbass
I was hoping to see you post some new plots of box/port tuning. Try using WinSD? I think using the new Xover at 100 Hz w/24 dB and tweeking the boxes, you could do well. Can you control/calculate midbass box volume in the kick panels? You might have to measure midbass Z and trim the box ports later tho, only if you have excursion problems.
Woofer
Any subwoofer worth its salt should be good to 200Hz.
Steeper filters are not well known for having the best transient behavior ...Yes your right, don't worry about transient and S/N.
Midbass:
I have got Unibox working and have been experimenting with different size boxes and tuning. Sadly I do not know how to post plots yet, maybe Monday. I having been using Winisd for a while, but after using Unibox, Winisd doesn't seem to provide important data.
Will there be a difference in sound between the coreect 2" or 3" or 4" port? Is one louder or tighter or something? I will be using flared ports.
Mids:
Did you check out the 3" Peerless I am using. It has gotten pretty good reviews on DIYMobileaudio and works well in a small box. Very transparent. Sensitivity is a low 84.2. when you say tiny, are you talking about someting smaller than a 3"?
I have got Unibox working and have been experimenting with different size boxes and tuning. Sadly I do not know how to post plots yet, maybe Monday. I having been using Winisd for a while, but after using Unibox, Winisd doesn't seem to provide important data.
Will there be a difference in sound between the coreect 2" or 3" or 4" port? Is one louder or tighter or something? I will be using flared ports.
Mids:
Did you check out the 3" Peerless I am using. It has gotten pretty good reviews on DIYMobileaudio and works well in a small box. Very transparent. Sensitivity is a low 84.2. when you say tiny, are you talking about someting smaller than a 3"?
mitchyz250f said:
The Orion/PPI DIN jacks have a bipolar voltage output (+/-15V) to power their accessories.
No +B or ground leads to connect to the car's system directly, they all run off the amp's power supply.
What this means to a DIY'er is that power supply and signal ground considerations are eliminated with the exception of a couple of small caps.
Note: I think it was PPI who actually called it "Phantom Power." Rockford Fosgate also used it in their DIN's, but was +/-18V.
Thanks for the invite, I'd love to have a listen. Been in the optical business the last 15 yrs, so I don't get too many opportunities to enjoy the fun stuff. I'm in way down south GA, but make it to ATL (~4 hr drive) and Macon (2 hrs) occasionally. Send me an email?
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.