Hi Tony,
Some queries here.
1. What are we looking at, when we do the measurements? Is it to have freq resp curve as flat as possible over the entire audio spectrum?
2. Correct me if I am wrong. I understand that, if there is dip at crossover freq, then reversing the tweeter polarity might solve the issue. Right?
3. In one of your previous replies you had said that any computer sound card will do. Is it so? I have lap top with mic in and line out. will it suffice? I am not sure if M-audio Mobilepre USB sound card is available in India that easily (to me atleast.) or such types may be too costly beyond my budget.
4. what type of mic is needed? The kind that stage performers and public speakers use..will it suffice.?
regards
prashant
Hi Prashant, I'll try to answer your questions.
1. partially 🙂 There are a number of factors, but the two most important are probably flat frequency response, and good phase matching. Both of which can be adjusted with the crossover. off axis frequency response is important too, but if the phase tracking is good it should probably also be good.
2. Yes if the phase tracking between the woofer and the tweeter is good, you should get a deep dip at the crossover frequency, assuming an even order crossover (2nd or 4th order acoustic)
3. I may have been a bit rash if I said that 😉 I suspect I said something along the lines of any on board sound card on a modern motherboard should be ok, I'd qualify that as it being what is generally called "high definition Audio". Laptops are a bit tricky. If you only have a laptop with a mic input and not a line input then you may be best off with a USB measuring microphone like this one Dayton Audio UMM-6 USB Measurement Microphone* | 390-808 I have a focusrite scarlet 2i2 usb sound card which is very good, but you would need to make up cables with one of those.
4. see above. One of the calibrated mics from places like partsexpress is probably your best bet. If you get a non-usb one you will likely also need a microphone preamplifier and a line in input on your sound card, so I think from an economy point of view the USB one is the most practical and cheapest solution.
If you have a web cam with a mic in it, you could do some experimenting with holm impulse and that, but the results will not be reliable enough for crossover modeling.
edit: this post has a comparison between two crossovers one with good phase tracking and one with not so good phase tracking 🙂 http://www.diyaudio.com/forums/multi-way/249702-do-i-just-have-tin-ears-4.html#post3790638
Tony.
1. partially 🙂 There are a number of factors, but the two most important are probably flat frequency response, and good phase matching. Both of which can be adjusted with the crossover. off axis frequency response is important too, but if the phase tracking is good it should probably also be good.
2. Yes if the phase tracking between the woofer and the tweeter is good, you should get a deep dip at the crossover frequency, assuming an even order crossover (2nd or 4th order acoustic)
3. I may have been a bit rash if I said that 😉 I suspect I said something along the lines of any on board sound card on a modern motherboard should be ok, I'd qualify that as it being what is generally called "high definition Audio". Laptops are a bit tricky. If you only have a laptop with a mic input and not a line input then you may be best off with a USB measuring microphone like this one Dayton Audio UMM-6 USB Measurement Microphone* | 390-808 I have a focusrite scarlet 2i2 usb sound card which is very good, but you would need to make up cables with one of those.
4. see above. One of the calibrated mics from places like partsexpress is probably your best bet. If you get a non-usb one you will likely also need a microphone preamplifier and a line in input on your sound card, so I think from an economy point of view the USB one is the most practical and cheapest solution.
If you have a web cam with a mic in it, you could do some experimenting with holm impulse and that, but the results will not be reliable enough for crossover modeling.
edit: this post has a comparison between two crossovers one with good phase tracking and one with not so good phase tracking 🙂 http://www.diyaudio.com/forums/multi-way/249702-do-i-just-have-tin-ears-4.html#post3790638
Tony.
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Hi Tony,
Thanks for your replies.
Parts express doesnt deliver in India. What I will do is, I will try experimenting with a webcam with built-in microphone first, just to ensure the that the set-up works and get a rough idea of measurement procedure. Then refine the equipments and set-up to accurately measure the freq-resp and model the cross over .
Here is the list of equipment I will be using (could you add to the list any missing equipments?)
1. Laptop
2. USB webcam with built-in microphone
3. Holmimpulse and ARTA
4.
Any other hardware or software?
Thanks for your replies.
Parts express doesnt deliver in India. What I will do is, I will try experimenting with a webcam with built-in microphone first, just to ensure the that the set-up works and get a rough idea of measurement procedure. Then refine the equipments and set-up to accurately measure the freq-resp and model the cross over .
Here is the list of equipment I will be using (could you add to the list any missing equipments?)
1. Laptop
2. USB webcam with built-in microphone
3. Holmimpulse and ARTA
4.
Any other hardware or software?
Hi Prashant, I've just realised that to do impedance measurements the standard way you need a line in input. I did see a post here on diyAudio by someone who has developed a solution for doing these measurements with the mic input on a laptop though http://www.diyaudio.com/forums/multi-way/216150-t-s-jig-limp-using-laptop.html.
I personally prefer REW for doing impedance measurements, but for acoustic measurements and getting used to how to how to do them the above + and amplifier (and hearing protection) should be all you need to get started.
Tony.
I personally prefer REW for doing impedance measurements, but for acoustic measurements and getting used to how to how to do them the above + and amplifier (and hearing protection) should be all you need to get started.
Tony.
Since I have just written it, you might also want to have a read of this post 🙂 http://www.diyaudio.com/forums/mult...ccurate-frd-zma-measurements.html#post3863078
Tony.
Tony.
Hi TONY,
I have taken my first measurement as per the first link that u had sent me. Red Spade Audio: How to measure your crossover with Holm Impulse.
I measured it with USB web cam (I dont know the quality of mic in it.) But the set up works!!!!
I did not measure the individual drivers (as they are in cabinet and wires are soldered)
I measured the overall response. I don't know what to make of the graphs. I am attaching one of the graphs ... Can tell me anything and what to do next?
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Hi tony,
what do u make of the dips at 3.5k, 8k and 15kHz? is it caused by mic quality . or the dip at 3.5 k is due to cross over?
regards
prashant
what do u make of the dips at 3.5k, 8k and 15kHz? is it caused by mic quality . or the dip at 3.5 k is due to cross over?
regards
prashant
Hi Pashant, more than likely 3.5Khz is due to crossover. Try reversing the polarity of the tweeter and re-measure. The dip is rather broad so if it is due to tweeter being wrong polarity it also indicates that the phase tracking is not the best, but not awful either. Ideally you should have a deep null when the tweeter is reversed.
The 8K and 15K dips may be diffraction effects, most likely due to the shape of the webcam. They are outside the range that would effect voice quality so webcam manufacturer would not be concerned by them. You could try angling the webcam to the speaker (say 45 deg) and see whether that changes the position of the dips.
The response up to 2Khz is very good!
Tony.
The 8K and 15K dips may be diffraction effects, most likely due to the shape of the webcam. They are outside the range that would effect voice quality so webcam manufacturer would not be concerned by them. You could try angling the webcam to the speaker (say 45 deg) and see whether that changes the position of the dips.
The response up to 2Khz is very good!
Tony.
Hi Tony,
You are great. I think you gave me the solution. After reversing the tweeter polarity, The dip is almost gone. i am attaching the image.
Should I ignore the dips at 8k and 15k ? I have see the F-R of tweeter and it quite flat from 1000 upto 20kH.
regards
prashant.
You are great. I think you gave me the solution. After reversing the tweeter polarity, The dip is almost gone. i am attaching the image.
Should I ignore the dips at 8k and 15k ? I have see the F-R of tweeter and it quite flat from 1000 upto 20kH.
regards
prashant.
Attachments
Looking at your speaker I very much doubt that the dips at 8K and 15K are due to the speaker. You don't really want those dips for doing crossover modelling though. I'm thinking that after reversing the tweeter they are going to be sounding a lot better now!
This shows that even without a decent measurement microphone you can use simple tools to idenitfy problems. This post from when I was going down the same initial path http://www.diyaudio.com/forums/multi-way/23465-speaker-workshop-microphone-invaluable.html 😀
I'll have a think about what the next steps should be. You may be better off with a usb sound card with mic inputs (that have phantom power). But cost is obviously a constraint.
Tony.
Tony.
This shows that even without a decent measurement microphone you can use simple tools to idenitfy problems. This post from when I was going down the same initial path http://www.diyaudio.com/forums/multi-way/23465-speaker-workshop-microphone-invaluable.html 😀
I'll have a think about what the next steps should be. You may be better off with a usb sound card with mic inputs (that have phantom power). But cost is obviously a constraint.
Tony.
Tony.
Hi Tony,
The speakers sound too good to believe now. Simply amazing...
I guess i will go ahead and buy that damn costly usb microphone. ... But to open assembled speakers again (if there is a problem) is pain I guess . ..... I am pretty lazy, to be frank!!....
Right now, I am enjoying my speakers with beer... cheers mate!!!
However I am planning to build a subwoofer powered by a plate amp. I will need plenty of help from you. I am hoping you will continue your amazing support ....
Again thanking you very much!!
prasi
The speakers sound too good to believe now. Simply amazing...
I guess i will go ahead and buy that damn costly usb microphone. ... But to open assembled speakers again (if there is a problem) is pain I guess . ..... I am pretty lazy, to be frank!!....
Right now, I am enjoying my speakers with beer... cheers mate!!!
However I am planning to build a subwoofer powered by a plate amp. I will need plenty of help from you. I am hoping you will continue your amazing support ....
Again thanking you very much!!
prasi
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Hi Prashant, If you are very happy with the result then perhaps leave the purchase of the microphone. Just enjoy the speakers you have built. If you get the itch to build some new speakers, or to try and optimize the ones you have (for potentially even better sound) then look at getting the mic then 🙂
When it comes to the sub, you should start a thread in the subwoofers forum. This is not really an area I have experience in (I'm going to build stereo subs for my MTM's The subs being the stands). But I can try to help out with what I know.
Tony.
When it comes to the sub, you should start a thread in the subwoofers forum. This is not really an area I have experience in (I'm going to build stereo subs for my MTM's The subs being the stands). But I can try to help out with what I know.
Tony.
Hi Prasi, I think that you need to work out whether you can do impedance measurements with your laptops built in sound before you buy any microphone. I'm not sure whether the circuit I linked to in post 44 will work with all laptops. I was not aware that laptop mic inputs had left and right channels, which nnx's jig seems to use.
If you cannot do impedance measurements you will not really be able to make proper use of accoustic measurements.
There are two paths you can go down if you can't do the impedance measurements with the built in sound card in your laptop.
a) buy something like the woofer tester II (which I think is around $160 US)
b) buy a USB sound card with proper line in and line out and make up a simple cable jig
option b will quite possibly be cheaper, and if you get a unit with mic preamps and phantom power you can get a proper mic (rather than USB) which will actually be cheaper than the USB one.
I have a focusrite scarlet 2i2 which is very good for doing measurements. I actually use it with my own mic preamp and home made mic, but I think something like the dayton EMM6 Dayton Audio EMM-6 Electret Measurement Microphone Allows For Accurate Acoustic Measurements At A Fraction Of The Price 390-801
Once you start down the measurement gear road the price will add up. I think realistically for a scarlett 2i2 one of the above mics and an XLR cable for the mic you would probably be looking at around $250 US.
If you can get the jig in post 44 to work then you could buy the US $60 usb mic and the jig would probably only cost maybe $5. so you would have the tools you need for around $65 US.
If you are happy with what you have, then spending more on test gear may not be necessary 🙂
Tony.
If you cannot do impedance measurements you will not really be able to make proper use of accoustic measurements.
There are two paths you can go down if you can't do the impedance measurements with the built in sound card in your laptop.
a) buy something like the woofer tester II (which I think is around $160 US)
b) buy a USB sound card with proper line in and line out and make up a simple cable jig
option b will quite possibly be cheaper, and if you get a unit with mic preamps and phantom power you can get a proper mic (rather than USB) which will actually be cheaper than the USB one.
I have a focusrite scarlet 2i2 which is very good for doing measurements. I actually use it with my own mic preamp and home made mic, but I think something like the dayton EMM6 Dayton Audio EMM-6 Electret Measurement Microphone Allows For Accurate Acoustic Measurements At A Fraction Of The Price 390-801
Once you start down the measurement gear road the price will add up. I think realistically for a scarlett 2i2 one of the above mics and an XLR cable for the mic you would probably be looking at around $250 US.
If you can get the jig in post 44 to work then you could buy the US $60 usb mic and the jig would probably only cost maybe $5. so you would have the tools you need for around $65 US.
If you are happy with what you have, then spending more on test gear may not be necessary 🙂
Tony.
Hi Tony,
Getting the "Itch" to improve my measurement set-up, so troubling you again.
Kindly have a look at this page and suggest if the unit is being sold here will serve the purpose.
Buy Online | Lowest Price | Free Shipping| SM Pro Audio XP200 RIAA EQ Unit with variable Gain - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
OR the both the behringer units (white in color) available here..
Buy Pre Amps Online | Lowest Price | Free Shipping - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
For the microphone, is this is suitable (USB)...
Buy Online | Lowest Price | Free Shipping| Samson Q1UCW Dynamic USB Microphone - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
or for XLR microphone, is this suitable
Buy Online | Lowest Price | Free Shipping| Samson C-05 CL Handheld Vocal Condenser Microphone - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
I dont know about inter connections /cables between these units and assuming I can find those from somewhere.
Also Somewhere in near future, I am planning to buy Zaph Audio ZA5.2 Kit from madisound and want to use them as my reference speakers. The Madisound Speaker Store
Am I right in doing so? I have read somewhere "Zaph audio kits are one of the top end true audiophile systems".
Prashant
Getting the "Itch" to improve my measurement set-up, so troubling you again.
Kindly have a look at this page and suggest if the unit is being sold here will serve the purpose.
Buy Online | Lowest Price | Free Shipping| SM Pro Audio XP200 RIAA EQ Unit with variable Gain - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
OR the both the behringer units (white in color) available here..
Buy Pre Amps Online | Lowest Price | Free Shipping - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
For the microphone, is this is suitable (USB)...
Buy Online | Lowest Price | Free Shipping| Samson Q1UCW Dynamic USB Microphone - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
or for XLR microphone, is this suitable
Buy Online | Lowest Price | Free Shipping| Samson C-05 CL Handheld Vocal Condenser Microphone - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India
I dont know about inter connections /cables between these units and assuming I can find those from somewhere.
Also Somewhere in near future, I am planning to buy Zaph Audio ZA5.2 Kit from madisound and want to use them as my reference speakers. The Madisound Speaker Store
Am I right in doing so? I have read somewhere "Zaph audio kits are one of the top end true audiophile systems".
Prashant
Hi Prasi, didn't get a chance to look at this yet, except the first link. You definitely don't want an RIAA device, that is for LP's 🙂 Might get a chance later tonight.
Tony.
Tony.
OK I think this is more like what you want if you want a budget external sound card for your laptop Buy Online | Lowest Price | Free Shipping| Behringer UCA222 U-Control - Summer Sale - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment in India review here NwAvGuy: Behringer UCA202 Review Note I did some searching and apparently the only difference between the 202 and the 222 is the colour, and the software bundled. The 222 is normally more expensive, but this one is actually cheaper.
It's only 16 bit 48Khz but for doing impedance measurements that would be more than enough. Even if you got a microphone and microphone preamp it would be fine for doing audio measurements as well. The other two you linked were also phono preamplifiers.
This is what I have Buy Online | Lowest Price | Free Shipping| Focusrite Scarlett 2i2 USB 2.0 Award Winning Audio Interface - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment but significantly more expensive and probably overkill. I wanted the 24bit 96Khz and balanced in and out, mainly because I intend to use it for measuring amplifiers and other electronics, not just for speaker measurements.
None of the microphones look like the sort of thing you want. That site does have the berhinger EMC8000 and I found this one too Buy Dayton Audio EMM-6 Electret Measurement Microphone at best price in india | ShopYourWorld both XLR mics, but would need a preamp, as the sound card above doesn't have a mic preamp.
I've not heard any zaph kits, but they are often mentioned as being good.
I've got to head for bed!
Tony.
It's only 16 bit 48Khz but for doing impedance measurements that would be more than enough. Even if you got a microphone and microphone preamp it would be fine for doing audio measurements as well. The other two you linked were also phono preamplifiers.
This is what I have Buy Online | Lowest Price | Free Shipping| Focusrite Scarlett 2i2 USB 2.0 Award Winning Audio Interface - Buy online at the guaranteed lowest price in India - BAJAAO - Buy online and Review Musical Instruments, Pro Audio, Studio, P.A. Audio Equipment but significantly more expensive and probably overkill. I wanted the 24bit 96Khz and balanced in and out, mainly because I intend to use it for measuring amplifiers and other electronics, not just for speaker measurements.
None of the microphones look like the sort of thing you want. That site does have the berhinger EMC8000 and I found this one too Buy Dayton Audio EMM-6 Electret Measurement Microphone at best price in india | ShopYourWorld both XLR mics, but would need a preamp, as the sound card above doesn't have a mic preamp.
I've not heard any zaph kits, but they are often mentioned as being good.
I've got to head for bed!
Tony.
Hi Tony
Thanks. The items suggested by you are within my budget. how ever pre-amp is a problem. I tried searching for the pre-amp but no results. So the measurement project is in jeopardy....:-(
reg
prashant
Thanks. The items suggested by you are within my budget. how ever pre-amp is a problem. I tried searching for the pre-amp but no results. So the measurement project is in jeopardy....:-(
reg
prashant
Hi Prasi, If you can get one of the dayton usb mic's then you don't need a preamp. You can use the USB sound card for generating your test tones and do accoustic measurements with the usb mic.
You can make a simple cable up to do impedance measurements using the line out and line in of the USB sound card. That will take care of all of your measurement needs.
Tony.
You can make a simple cable up to do impedance measurements using the line out and line in of the USB sound card. That will take care of all of your measurement needs.
Tony.
Dear Tony,
I request you to kindly visit the following link
http://www.diyaudio.com/forums/subwoofers/254327-subwoofer-dayton-audio-sd270a-88-dvc.html
The link is about the ported sub that I am going to build. I have taken some help from "Inductor" but I also would like to have your inputs as well. As you have helped a lot for my bookshelf (though I admit I did not go through with measurement suggestions because of availability of hardware and budget constraints; sorry for that.) , I would like to have your help in this project also.
regards
Prasi
I request you to kindly visit the following link
http://www.diyaudio.com/forums/subwoofers/254327-subwoofer-dayton-audio-sd270a-88-dvc.html
The link is about the ported sub that I am going to build. I have taken some help from "Inductor" but I also would like to have your inputs as well. As you have helped a lot for my bookshelf (though I admit I did not go through with measurement suggestions because of availability of hardware and budget constraints; sorry for that.) , I would like to have your help in this project also.
regards
Prasi
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