I've almost got myself convinced to purchase a Radio Shack Sound Pressure Level Meter. Though it is hard to justify on my poverty level income.
And poverty is the reason for this post.
Is there anything better for the money that either of the Radio Shack Meters?
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=sound meter&origkw=sound meter&sr=1
The stated frequency response is 30hz to 10khz which seem better than most economy SPL meters.
So, now the choices are analog meter or digital read-out.
I would think with an analog meter display I would get a better sense of the dynamics of the music, but couldn't take such precise readings.
The Digital has precision, but lacks the display dynamics.
I'm open to opinions on the Radio Shack, and to suggestions for better SPL meters for similar money.
Though, since I am already stretching my budget, I can't spend much more that $50.
Suggestions? Opinions? Ideas? Options? Whatever?
Thanks.
Steve/bluewizard
And poverty is the reason for this post.
Is there anything better for the money that either of the Radio Shack Meters?
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=sound meter&origkw=sound meter&sr=1
The stated frequency response is 30hz to 10khz which seem better than most economy SPL meters.
So, now the choices are analog meter or digital read-out.
I would think with an analog meter display I would get a better sense of the dynamics of the music, but couldn't take such precise readings.
The Digital has precision, but lacks the display dynamics.
I'm open to opinions on the Radio Shack, and to suggestions for better SPL meters for similar money.
Though, since I am already stretching my budget, I can't spend much more that $50.
Suggestions? Opinions? Ideas? Options? Whatever?
Thanks.
Steve/bluewizard
What do you want it for? They are fun to play with, but not as useful as real measurements. They are flat from ~60-1k, then rise about 6+dB to ~6kHz, then drop back to 0dB by 10kHz and are -12 to -20 at 20kHz. Analog is better than digital, IMO, except that you can bust the analog movement if you aren't careful.
The Audio society of MN (www.audiomn.org) is having a meeting Tuesday the 17th, if you can make it.
The Audio society of MN (www.audiomn.org) is having a meeting Tuesday the 17th, if you can make it.
fwater said:
Sorry, we are in the process of moving, need to change our domain registration - a better link would be:
http://sites.google.com/site/audiosocietyofminnesota/
This link is on the original page I linked to. A successful tweeker is going to talk about equipment mods and tweeks and such - see the meeting announcement by clicking the link in the sidebar on the front page. Aside from the meeting topics there are often side room discussions of value.
I'm in sunny southern Minnesota, or as I like to call it audio hell.
Though, I've never had an exceptionally expensive system, it's always been the best system of anyone I knew. But that says more about the quality of my friends, than it does about my stereo equipment.
I have some speakers I built back in college, and while they have served me well for many many years, they are not that well balanced.
Last summer I rebuilt them hoping to improve the bass, and tame an overly aggressive midrange. So, I re-ported the cabinet, put a fixed L-Pad attenuator in the tweeter and the midrange. But now I think I've tone down the treble too much, and the midrange not enough, and I'm wondering about the port tuning.
Also, when I pleaded poverty, I wasn't kidding. So, I'm working on a dirt poor budget here.
First, I though I could do a general frequency response on the speakers, though 10khz would probably be adequate for the speakers I have. That is, the mid to high crossover is 5khz, so if I can get significantly above that, it's probably close enough.
Plus the only source of test signal I have are test tones burned onto a CD (actually, 3 CD's - 10hz to 300hz, 1/3 octave tones, 1/6 octave tones)
Next, I'd like to check the actual port resonance. It seem if I put the SPL meter right up to the port and ran a low end frequency sweep, I could determine the actual resonance point, and re- tune it if necessary.
Finally, I like to run some Pink Noise and measure the woofer, midrange, and tweeter individually at close range to determine the real loudness balance between them. Which in turn would allow me to determine the right attenuation to use to balance the three component speakers.
Again, my speakers are old. I don't think it is possible to get the specs on the woofers. I've already contacted CTS to no avail. But the design book I used has some margin notes indicating that the woofer has a resonance of 25hz. It is a 12" CTS with a 32 ounce magnet. The midrange is a 4" x 10" horn, and the tweeter is a 3" x 3" piezo horn. The piezo tweeter has an 8 ohm resistor across the terminals to stabilize the load and it connected to a 3-way crossover crossing at 800hz and 5khz.
The cabinet is about 2.5 cubic feet with a 2" diameter by 4" deep flared port. When I tuned the port, to correct for components taking up room inside the cabinet, I used 2.3 cu.ft. as the internal volume.
Because the midrange horn is so loud, something like 108db/1 watt, I have an L-Pad on it, and it is turned down nearly as far as it will go. But still isn't quite right.
I've considered just getting some software and using my computer to test the speakers, but the entry cost is too high. Even a half-a$$ed job of it is going to cost $150 minimum. But in reality, if I were going to do it even remotely right, it would be more like $500. That's out of my league unless I win the lottery. So, it seems like the SPL meter might be the only option for me. But it is hard to justify the cost when that money could go for groceries, or car repairs, or other unexpected expenses.
I currently have my speakers sitting along side some JBL Venue Stadiums (2x8", 3" cone mid, 1" done high). The JBL seem long on bass but weak in midrange, and my 12" DIY CTS speakers are lean, but clear, on bass and long on midrange. Between the two of them, they sound pretty good.
Still, I either obsess over the idea until it drives me nuts, or just just spend the money and do what needs to be done.
How consistent is the frequency response of the Radio Shack Digital Meter? Are there response correction files for it that I could use to manually correct the readings I take?
One thing I will say about my woofers is that for having been purchase in the very early 80, the cones and surrounds are in pristine condition. The surrounds are as soft and pliable as the day I bought the speakers; not a hint of decay or deterioration.
So, that is my long sad story.
So, I'm looking to maximize my money. Hence the question, is there anything better for the money than the Radio Shack?
Thanks for the info about the Minnesota Audio Society, if I ever win the lottery, I'll come knocking.
Steve/bluewizard
Though, I've never had an exceptionally expensive system, it's always been the best system of anyone I knew. But that says more about the quality of my friends, than it does about my stereo equipment.
I have some speakers I built back in college, and while they have served me well for many many years, they are not that well balanced.
Last summer I rebuilt them hoping to improve the bass, and tame an overly aggressive midrange. So, I re-ported the cabinet, put a fixed L-Pad attenuator in the tweeter and the midrange. But now I think I've tone down the treble too much, and the midrange not enough, and I'm wondering about the port tuning.
Also, when I pleaded poverty, I wasn't kidding. So, I'm working on a dirt poor budget here.
First, I though I could do a general frequency response on the speakers, though 10khz would probably be adequate for the speakers I have. That is, the mid to high crossover is 5khz, so if I can get significantly above that, it's probably close enough.
Plus the only source of test signal I have are test tones burned onto a CD (actually, 3 CD's - 10hz to 300hz, 1/3 octave tones, 1/6 octave tones)
Next, I'd like to check the actual port resonance. It seem if I put the SPL meter right up to the port and ran a low end frequency sweep, I could determine the actual resonance point, and re- tune it if necessary.
Finally, I like to run some Pink Noise and measure the woofer, midrange, and tweeter individually at close range to determine the real loudness balance between them. Which in turn would allow me to determine the right attenuation to use to balance the three component speakers.
Again, my speakers are old. I don't think it is possible to get the specs on the woofers. I've already contacted CTS to no avail. But the design book I used has some margin notes indicating that the woofer has a resonance of 25hz. It is a 12" CTS with a 32 ounce magnet. The midrange is a 4" x 10" horn, and the tweeter is a 3" x 3" piezo horn. The piezo tweeter has an 8 ohm resistor across the terminals to stabilize the load and it connected to a 3-way crossover crossing at 800hz and 5khz.
The cabinet is about 2.5 cubic feet with a 2" diameter by 4" deep flared port. When I tuned the port, to correct for components taking up room inside the cabinet, I used 2.3 cu.ft. as the internal volume.
Because the midrange horn is so loud, something like 108db/1 watt, I have an L-Pad on it, and it is turned down nearly as far as it will go. But still isn't quite right.
I've considered just getting some software and using my computer to test the speakers, but the entry cost is too high. Even a half-a$$ed job of it is going to cost $150 minimum. But in reality, if I were going to do it even remotely right, it would be more like $500. That's out of my league unless I win the lottery. So, it seems like the SPL meter might be the only option for me. But it is hard to justify the cost when that money could go for groceries, or car repairs, or other unexpected expenses.
I currently have my speakers sitting along side some JBL Venue Stadiums (2x8", 3" cone mid, 1" done high). The JBL seem long on bass but weak in midrange, and my 12" DIY CTS speakers are lean, but clear, on bass and long on midrange. Between the two of them, they sound pretty good.
Still, I either obsess over the idea until it drives me nuts, or just just spend the money and do what needs to be done.
How consistent is the frequency response of the Radio Shack Digital Meter? Are there response correction files for it that I could use to manually correct the readings I take?
One thing I will say about my woofers is that for having been purchase in the very early 80, the cones and surrounds are in pristine condition. The surrounds are as soft and pliable as the day I bought the speakers; not a hint of decay or deterioration.
So, that is my long sad story.
So, I'm looking to maximize my money. Hence the question, is there anything better for the money than the Radio Shack?
Thanks for the info about the Minnesota Audio Society, if I ever win the lottery, I'll come knocking.
Steve/bluewizard
someone else will be able to provide a link, but I believe you can build your own with a panasonic capsule. that should be cheap enough!
\
a few bibs and bobs to get the signal into your computer (also described I think) and you're away.
anyway, download rew and forget all that cd's with sine waves business. use their generic cal file for the rs meter, and if all you are doing is checking relative driver levels it may be all you need.
while you are at it, you cN NOW measure your in room response, rs meter perfectly adequate for that.
\
a few bibs and bobs to get the signal into your computer (also described I think) and you're away.
anyway, download rew and forget all that cd's with sine waves business. use their generic cal file for the rs meter, and if all you are doing is checking relative driver levels it may be all you need.
while you are at it, you cN NOW measure your in room response, rs meter perfectly adequate for that.
BlueWizard said:
I have frequency response measurements I made with 1/3 octave pink noise and a RS SPL meter on some speakers I own and they don't look anything like accurate frequency response curves on the same speakers do, with or without corrections.
If you can burn a CD, you can play test tones through your computer.
An RS SPL meter is not useful for measuring port resonance by putting it on the port, the port output may be broad or narrow - the best way is to close mike the woofer and look for a notch.
You can calculate port resonance from what you have provided.
To measure Frequency response a DIY mic with a panasonic capsule and the program Speaker Workshop will be much better than even a RS SPL and a generic "calibration". Pretty low cost of entry.
Again ... Poverty.
REW?
Real Estate World?
REW: Summary for ULTRASHORT TECHNOLOG... ?
*Rew* ... NYC's Punk Sweetheart. ... often called …a ‘female Velvet Underground’.
Rew Materials ...distributes interior and exterior construction products,
How about the full name and possibly a link?
Next, while the base Pansonic Mic can be had for very little. I think about $1.86 from Digi-Key (Panasonic WM-61A, Digi-Key P9925-ND), I'm pretty sure Digi-Key has a minimum order. I used to be $25, though I haven't done business with them in a long time.
But then I have to make some kind of case to hold the Mic. PVC pipe isn't that bad, but for pipe that small, I probably have to buy a whole pipe. The mics I've seen built into PVC pipe have a small section then flare into a larger section. So, I have to buy two pipes and assorted junctions and caps.
Then I have to buy a connector (XLR or stereo phone) for the pipe/mic, about $5. Then I need shielded cable ($10). Then I need so type of mixer, or at least a box to add phantom power, and to beak out the signal to the computer (+$20). Throw in an adapter or two and the price is up there.
Or, I could just buy the Behringer ECM8000 mic for $50. But I still need additional parts to get it to work with my computer.
Then I need a new sound card. The one I have is a very basic card built on to the motherboard (RealTek). It is adequate for most general computer use, but is marginal for audio testing. Still, I could probably get by with what I have.
Next, I have to either bring my desktop computer to my stereo, or my stereo to my desktop computer. That certainly can be done, but it is less than ideal.
It may sound like I am simply making excuses, but what I'm trying to say is I have contemplated all the possibilities and their associated costs.
I'm really only trying to find out a few basic things. I think I can find the port's peak output easy enough regardless of whether it is broad or narrow. I know I can calculate the theoretical resonance, and that is exactly how I arrived at the port I have. I don't need a precise frequency response, though that would certainly be nice to have; all I really need is to balance low, mid, and high. So, pink noise plus three readings and I'm there.
Trust me, if there was anyway I could pull it off with a real microphone, associated equipment, and my computer, I would be on it.
I haven't completely discounted the Panasonic microphone at some point in the future. But it is not as simple has having the mic. There are other bits and bobs that go along with it, and like any project, I see a massive price creep. It starts out at $2 and creep up well over $100.
I rebuilt these speakers last summer, nothing too complex, a new port, new insulation, used the same crossovers but rewired them to make the speaker easier to work on, re-enforced the cabinets, new connector plate, etc.... The final price crept up around $200, and again, that is using the same crossovers, the same drivers, and the same box. I know about price creep.
The basic M-Audio 'Audio Buddy' Pre-Amp can be had for $100 or less, and the Behringer mic can be had for $50. That would take me a long way toward being ready to go, but that is still $150. Which is what I said would be the entry level cost to use a computer.
Again, at this stage, I only need some very basic information to help me move to the next level with these speakers. The speakers do sound generally good, I happily listen to them everyday, but I think I can improve them further, but I have to do it at minimum cost.
If I has a steady flow on significant income, I wouldn't hesitate to drop $1,000 on software and equipment to design and test speakers. But, I really don't see that happening anytime soon.
Thanks again for all the responses. I do understand the points you are making and have considered them.
Steve/bluewizard
REW?
Real Estate World?
REW: Summary for ULTRASHORT TECHNOLOG... ?
*Rew* ... NYC's Punk Sweetheart. ... often called …a ‘female Velvet Underground’.
Rew Materials ...distributes interior and exterior construction products,
How about the full name and possibly a link?
Next, while the base Pansonic Mic can be had for very little. I think about $1.86 from Digi-Key (Panasonic WM-61A, Digi-Key P9925-ND), I'm pretty sure Digi-Key has a minimum order. I used to be $25, though I haven't done business with them in a long time.
But then I have to make some kind of case to hold the Mic. PVC pipe isn't that bad, but for pipe that small, I probably have to buy a whole pipe. The mics I've seen built into PVC pipe have a small section then flare into a larger section. So, I have to buy two pipes and assorted junctions and caps.
Then I have to buy a connector (XLR or stereo phone) for the pipe/mic, about $5. Then I need shielded cable ($10). Then I need so type of mixer, or at least a box to add phantom power, and to beak out the signal to the computer (+$20). Throw in an adapter or two and the price is up there.
Or, I could just buy the Behringer ECM8000 mic for $50. But I still need additional parts to get it to work with my computer.
Then I need a new sound card. The one I have is a very basic card built on to the motherboard (RealTek). It is adequate for most general computer use, but is marginal for audio testing. Still, I could probably get by with what I have.
Next, I have to either bring my desktop computer to my stereo, or my stereo to my desktop computer. That certainly can be done, but it is less than ideal.
It may sound like I am simply making excuses, but what I'm trying to say is I have contemplated all the possibilities and their associated costs.
I'm really only trying to find out a few basic things. I think I can find the port's peak output easy enough regardless of whether it is broad or narrow. I know I can calculate the theoretical resonance, and that is exactly how I arrived at the port I have. I don't need a precise frequency response, though that would certainly be nice to have; all I really need is to balance low, mid, and high. So, pink noise plus three readings and I'm there.
Trust me, if there was anyway I could pull it off with a real microphone, associated equipment, and my computer, I would be on it.
I haven't completely discounted the Panasonic microphone at some point in the future. But it is not as simple has having the mic. There are other bits and bobs that go along with it, and like any project, I see a massive price creep. It starts out at $2 and creep up well over $100.
I rebuilt these speakers last summer, nothing too complex, a new port, new insulation, used the same crossovers but rewired them to make the speaker easier to work on, re-enforced the cabinets, new connector plate, etc.... The final price crept up around $200, and again, that is using the same crossovers, the same drivers, and the same box. I know about price creep.
The basic M-Audio 'Audio Buddy' Pre-Amp can be had for $100 or less, and the Behringer mic can be had for $50. That would take me a long way toward being ready to go, but that is still $150. Which is what I said would be the entry level cost to use a computer.
Again, at this stage, I only need some very basic information to help me move to the next level with these speakers. The speakers do sound generally good, I happily listen to them everyday, but I think I can improve them further, but I have to do it at minimum cost.
If I has a steady flow on significant income, I wouldn't hesitate to drop $1,000 on software and equipment to design and test speakers. But, I really don't see that happening anytime soon.
Thanks again for all the responses. I do understand the points you are making and have considered them.
Steve/bluewizard
REW = room equalization wizard from home theater shack, IIRC
I think you need to get out of your "can't afford it" mode and get into git'r'done mode. Someone here might have a capsule laying around they could send you for <$5 - all you need do is ask. For <$5 you can build a "good enough" powering circuit for it - even less if you have a broken pair of stereo headphones laying around with a decent cord. You can even use the mic input on your sound card and forget about the powering ckt, but that isn't ideal.
A piece of brass or aluminum tubing costs a buck or two - or you could use the barrel of a freaking pen, FWIW....
RS SPL is for making noise measurements in a factory and possibly for balancing a Home theater or setting a sub level. For speaker frequency response measurements I am telling you I have tried it and found it wanting...
I'm done, good luck.
I think you need to get out of your "can't afford it" mode and get into git'r'done mode. Someone here might have a capsule laying around they could send you for <$5 - all you need do is ask. For <$5 you can build a "good enough" powering circuit for it - even less if you have a broken pair of stereo headphones laying around with a decent cord. You can even use the mic input on your sound card and forget about the powering ckt, but that isn't ideal.
A piece of brass or aluminum tubing costs a buck or two - or you could use the barrel of a freaking pen, FWIW....
RS SPL is for making noise measurements in a factory and possibly for balancing a Home theater or setting a sub level. For speaker frequency response measurements I am telling you I have tried it and found it wanting...
I'm done, good luck.
You can buy a Behringer mic preamp/mixer or other inexpensive preamp for about $50. As long as your onboard soundcard does full duplex measurements, you should be able to measure with a tool like speaker workshop (free) or other freeware/demo software such as ARTA.
I normally measure in my garage or in the driveway and leave my PC in my office. You can run pretty long patch cables from the mic preamp to the PC, just keep the mic to preamp cable relatively short.
Regards,
Dennis
I normally measure in my garage or in the driveway and leave my PC in my office. You can run pretty long patch cables from the mic preamp to the PC, just keep the mic to preamp cable relatively short.
Regards,
Dennis
I use the panasonic capsules all the time. The design from linkwitz's site (http://linkwitzlab.com/sys_test.htm#Mic) costs under $20, and includes a preamp. I modify his design to include a volume control in the preamp. They are very accurate (the only caveat being that they usually have a 2-3dB bump centered around 10k - usually not a big problem), more so than the Behringer, and way more than the radio shack meter - but it can only tell you dB SPL unless you have it calibrated, which isn't at all necessary.
The software is another thing though - I tried Speaker Workshop, which is free, but doesn't work very well, so I bought Soundeasy. ARTA is a free program people seem to like - http://www.fesb.hr/~mateljan/arta/
Building the panasonic mic is pretty easy (IMO). If you want, I have a capsule I could send you (already modified, with wires attached!). Send me a PM. Also, if you do the linkwitz mic (which my capsules are modified for), you can get away with a 5532 opamp, rather than the OPA2134 Linkwitz suggests (its cheaper). Neither Mouser or Digikey has minimum orders.
The software is another thing though - I tried Speaker Workshop, which is free, but doesn't work very well, so I bought Soundeasy. ARTA is a free program people seem to like - http://www.fesb.hr/~mateljan/arta/
Building the panasonic mic is pretty easy (IMO). If you want, I have a capsule I could send you (already modified, with wires attached!). Send me a PM. Also, if you do the linkwitz mic (which my capsules are modified for), you can get away with a 5532 opamp, rather than the OPA2134 Linkwitz suggests (its cheaper). Neither Mouser or Digikey has minimum orders.
I've built plenty of Panasonic mikes. Go to a hobby shop and buy a brass tube, maybe 12" long, mount it in that. You can wrap the tube in black vinyl tape for looks and to damp it.
Cut the end of a shielded RCA cable and solder the unterminated end to the microphone capsule.
You will need power, 4 AA or a 9V battery in a little plastic box with RCA connectors in and out is fine. Get all this from Digi-key or Rat shack. In most cases you wont need an amp behind the microphone. You can cheap out and skip the box if looks are not essential.
Use your "marginal" sound card. It will probably never limit you in any way except for very low end response. If not full duplex, make a test CD.
Another free program is the 1/3 octave free mode of the software from liberty instruments. get it here
http://www.libinst.com/
Only reason to get the Rat Shack meter is if you want to get a somewhat calibrated feel for how load the speakers are playing, i.e. is it 85dBA or 100dBA? That's about all it's good for in my opinion. I would never trust any signals coming out of it for analysis for a lot of reasons, especially over 3-5KHz.
Cut the end of a shielded RCA cable and solder the unterminated end to the microphone capsule.
You will need power, 4 AA or a 9V battery in a little plastic box with RCA connectors in and out is fine. Get all this from Digi-key or Rat shack. In most cases you wont need an amp behind the microphone. You can cheap out and skip the box if looks are not essential.
Use your "marginal" sound card. It will probably never limit you in any way except for very low end response. If not full duplex, make a test CD.
Another free program is the 1/3 octave free mode of the software from liberty instruments. get it here
http://www.libinst.com/
Only reason to get the Rat Shack meter is if you want to get a somewhat calibrated feel for how load the speakers are playing, i.e. is it 85dBA or 100dBA? That's about all it's good for in my opinion. I would never trust any signals coming out of it for analysis for a lot of reasons, especially over 3-5KHz.
sounds like you have had some good advice and offers of help on the how to for that panasonic.
here is rew http://www.hometheatershack.com/
if you get the ecm (only $50 you said) then the cheapest mixer is xenyx 602 (??), again $50 over there?
program is free, and you are out of trouble.
here is rew http://www.hometheatershack.com/
if you get the ecm (only $50 you said) then the cheapest mixer is xenyx 602 (??), again $50 over there?
program is free, and you are out of trouble.
I have one (actually a couple) of the Panasonic mics using the Linkwitz pre I would be willing to sell. I used a 9v battery for power. Has an on/off switch as well. Aluminum arrow shaft for a boom, PVC pipe to house the battery and delrin plastic ends. I even put in a 4 ft cord with a 1/8 mini plug that will go right into a standard sound card. I can post a pic if your interested. $30.00 ($25.00 + $5.00 shipping.)
Thanks again for all the replies, I do appreciate it, and appreciate you are trying to get me to 'upgrade'.
I did contact Digi-Key, which is in Minnesota, and they do NOT currently have a minimum order.
Can anyone tell me the diameter of the Panasonic mic. I think I have an exaggerated view of it. Is it 1/4"? 3/8"? 1/2"?
Still even on the cheap, it cost nearly the price of a new mic to build your own. Agian, price creep. My theory is the Theory of Three. How long will it take? Make you best guess and multiply by three. How much will it cost? Make your best guess and multiply by three. It actually comes very close.
I will admit the Panasonic option is becoming more appealing. And I will look into it further.
I think I might actually have ARTA and Speaker Workshop installed, but haven't played with them much because I don't have a mic and mixer.
Again, thanks for the replies.
Steve/bluewizard
I did contact Digi-Key, which is in Minnesota, and they do NOT currently have a minimum order.
Can anyone tell me the diameter of the Panasonic mic. I think I have an exaggerated view of it. Is it 1/4"? 3/8"? 1/2"?
Still even on the cheap, it cost nearly the price of a new mic to build your own. Agian, price creep. My theory is the Theory of Three. How long will it take? Make you best guess and multiply by three. How much will it cost? Make your best guess and multiply by three. It actually comes very close.
I will admit the Panasonic option is becoming more appealing. And I will look into it further.
I think I might actually have ARTA and Speaker Workshop installed, but haven't played with them much because I don't have a mic and mixer.
Again, thanks for the replies.
Steve/bluewizard
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.