2 Way speakers - Suggestions on improvements?

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Yea =)

I think their prices are great, i don't know how many components or whatever i need in the end but im sure i can find something there that will do well. They seem to have everything from "budget" to the highest of highend. I guess i can choose what "level" to get when i sum it all up 🙂

Okey, i will leave them totally unmodified to start with!

The caps i have put in now is new and all identical:
http://www.farnell.com/datasheets/1723232.pdf
I use 2x10uF to make a bipolar 5uF cap =)

I will use only the "right speaker" for experiments and measurements, its the speaker that has the best seal from speaker to baffle.

So, i will start with these measurements:
Circumstances:
  • 3ft in front of tweeter
  • Tripod for mic
  • All screws in place
  • Max 2,85v output level
  • Tweeter on top
  • Full - Left Speaker
  • Full - Right Speaker
  • Tweeter only with 5uF bipolar cap in box - Right Speaker
  • Woofer only in box - Right Speaker

Good start? =)
 
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Yep. I would turn the speaker around so the tweeter is on top for measurements.

Yes, but we'll only need 1 full set (Full, Tweet only, woofer only) for interferometry. The distance will be the same. Up to you if you want to do them all.

Best,

Erik
 
Oh, wait.

We can use the 5uF cap with the tweeter for interferometry but we'll still need a full range tweeter measurement for proper simulation. Again, those particular tweeters are pretty rugged. Just keep your power low or eliminate test signals < 500 Hz and you'll be good.

Best,


Erik
 
Missed one more thing. 🙂 if you can get as close as possible to 2.828 V it's ideal, because then we can simulate with real power figures. If not, let's say you can only measure 2.8V, just keep the volume from changing between measurements so it's all at the same level.
 
2.828 V = 1W into 8 Ohms. So it's a standard sensitivity measurement which is what XSim and other tools are expecting. It's fine if your speakers are 4 or even 1 ohm. What's important for this is being close to the reference voltage. If you can't be, you can still do all your crossover design, but you will only have relatively accurate SPL simulation instead of absolutely accurate. 🙂

Erik
 
Missed one more thing. 🙂 if you can get as close as possible to 2.828 V it's ideal, because then we can simulate with real power figures. If not, let's say you can only measure 2.8V, just keep the volume from changing between measurements so it's all at the same level.
Ill do my best but i dont know how accurate my multimeter is, its not a fancy one unfortunatley. But i will set the level with a 50Hz tone as close as possible.
EDIT - I have 2digits accuracy on the display.
 
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Ah, okey. I will do one full range sweep with the cap and one limited to 500Hz+?

Or, my plan was to do all measurements with the 2.83V so then i can do a full sweep of the tweeter without the cap at that level then?

Let's keep this simple since you have a rugged tweeter. The fact that it hasn't blown by now is a good indicator it never will. 🙂

Do a full range with the cap now just so you can remember where you started from. 😉 This will help you see how far you've come when you're done.

Jumper around the cap, and do your 3 measurements. Full, tweet only, woofer only at 2.83V.

Best,

Erik
 
Let's keep this simple since you have a rugged tweeter. The fact that it hasn't blown by now is a good indicator it never will. 🙂

Do a full range with the cap now just so you can remember where you started from. 😉 This will help you see how far you've come when you're done.

Jumper around the cap, and do your 3 measurements. Full, tweet only, woofer only at 2.83V.

Best,

Erik
Haha, great!

Yea, i will do that and print the results and hang them on the wall next to the new once 😉

Okey, i will do it like that then!
 
Circumstances:
  • 3ft in front of tweeter
  • Tripod for mic
  • All screws in place
  • Max 2,85v output level
  • Tweeter on top

Measurements:
  • Full - Left Speaker
  • Full - Right Speaker
  • Full no cap - Right Speaker
  • Tweeter only in box no cap - Right Speaker
  • Woofer only in box - Right Speaker
 
Hum, im not getting any reading what so ever from the multimeter when i try to measure the output voltage. I have tried with the speaker connected as well without results, tried 50Hz 500Hz and music all in different volume settings. Meter shows 0.00 no matter what at all different settings, DC and AC. Tried to measure a regular AAA battery and it reads 1,49V. Am i stupid?
 
Hum, im not getting any reading what so ever from the multimeter when i try to measure the output voltage. I have tried with the speaker connected as well without results, tried 50Hz 500Hz and music all in different volume settings. Meter shows 0.00 no matter what at all different settings, DC and AC. Tried to measure a regular AAA battery and it reads 1,49V. Am i stupid?

Use ac only. you shou,d start with volume off, then increase slowly. Use a speaker to listen for output.
 
Setmeter on ac. rub on and off battery. you should get something. If not maybe meter is not working. If that works, trycarefully on wall outlet.

Make sure you measurr AC Volts and that auto range hold is not on.
 
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I think i need to get another multimeter, its an none auto range one so AC range is 200 or 600V. I guess you need a multimeter with true RMS to measure it? Unfortunately the shops are closed for the night now =/
Hum, maby i could smoothen the signal and measure it in DC? Or hack something together with the ADC on an arduino to get something at least.
 
I think i need to get another multimeter, its an none auto range one so AC range is 200 or 600V. I guess you need a multimeter with true RMS to measure it? Unfortunately the shops are closed for the night now =/
Hum, maby i could smoothen the signal and measure it in DC? Or hack something together with the ADC on an arduino to get something at least.

oooh, no wonder. 🙂 That range is a little high. 🙂 You need something that can read 0 to 10 V or something as part of it's range. 🙂

True RMS is cool, but we don't need it since your test generator will generate a clean 60 Hz sine wave, any working V meter will read correctly.

True RMS meters are more accurate only when your signal is not guaranteed to be a low distortion sine wave. Also, different meters have different sensitivities to high frequency (> 60 Hz) AC, but ALL modern mutlimeters read accurately between 50 and 60 Hz to make sure they can read wall outlet voltage correctly. Fancier one's will read up to the kHz or beyond. This is why I suggested a 50 to 60Hz test signal. In this range, there's no reason to pay more for "True RMS" but of course those meters tend to come with more cool features. 🙂

I happen to have an old Fluke 77 which reads accurately up to around 3-5kHz (forgot exactly) and has True RMS but at 60 Hz with a sine wave is no more accurate than others.

It's OK for us to be a little off too. We're not selling your speaker design. The goal is just to make sure we're in the ballpark and that all measurements occur at the same volume for the initial driver to driver measurements and that we don't run the risk of overloading anything.
 
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Haha, this cheap multimeter has always been good enought for my needs but i haven't tried to measure waves before ^^

Thanks for the explination of True RMS =)

This would do just fine then? Uni-Trend Group Limited
I was thinking of getting a meter with autorange anyway, nice to have when probing resistors!

For us that looks great! It has a very useful 4V range. Look at the accuracy figures. Maybe if you work for the AC company and need to decide whether to redistribute power to a low or high voltage area that is too much, but for us, 1.3% is just fine.

Best,


Erik
 
Great, then ill get it tomorrow after work!

I did a full sweep on both speakers before i tried to set the voltage, ill post it here as a comparison of the two:

Full no voltage limit - Right Speaker
IT6cLgu.png


Full no voltage limit - Left Speaker
KjWjNFg.png


I think they look quite similar? 🙂
 
They were in the "middle" of the room, or rather in the middle of the empty space in front of the tv/stereo. Wall was 1m from the side and 1,5m from the back.

The graphs above is limited to 50db, here is one with 100db to fit the entire result:

Full no voltage limit 100db - Right Speaker
WNRavFp.png


Full no voltage limit 100db - Left Speaker
wfwMUmV.png
 
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