Measuring the SPL of loudspeaker at home.

Pano · 2013-10-06 5:16 pm

Cool! You're getting there. Looks good. :up:

Now we just need to look at the individual driver responses. Do you know how to do that?

Pano · 2013-10-06 5:24 pm

Targets

FYI, here is a HOLM file with 2 target response slopes in it. This is the target I use for my room, it sounds the most natural. As you system is similar, this may work for you. One is rolled off at the ends to match what my system is capable of, the other is just a straight slope.

You might find this curve handy as an in room target.

RamJBL · 2013-10-06 5:30 pm

Pano said:
Cool! You're getting there. Looks good. Now we just need to look at the individual driver responses. Do you know how to do that?

I don't think so, but with your help, I think I can.

Pano said:
FYI, here is a HOLM file with 2 target response slopes in it. This is the target I use for my room, it sounds the most natural. As you system is similar, this may work for you. One is rolled off at the ends to match what my system is capable of, the other is just a straight slope.

You might find this curve handy as an in room target.

I don't know how to open and use these files. Should I somehow open them with HOLM? Can you give me a hint.

RamJBL · 2013-10-06 5:35 pm

Pano said:
Cool! You're getting there. Looks good. Now we just need to look at the individual driver responses. Do you know how to do that?

Can I just turn off the other drivers and do the same measurements with only one driver?

Pano · 2013-10-06 6:16 pm

Check your private messages

a.wayne · 2013-10-06 6:38 pm

Again , i suggest you drag it outside and compare curves , by doing so you have a reference to compare to your gated response. You can of course measure the drivers separately as suggested by pano, gated may get good accuracy down to 500 hz and then measure the woofer in its pressure zone , scale and splice ...

RamJBL · 2013-10-06 6:50 pm

a.wayne said:
Again , i suggest you drag it outside and compare curves , by doing so you have a reference to compare to your gated response. You can of course measure the drivers separately as suggested by pano, gated may get good accuracy down to 500 hz and then measure the woofer in its pressure zone , scale and splice ...

The problem is, it is almost impossible for me to drag them out. They are too heavy and too many stairs.

BlueWizard · 2013-10-06 7:01 pm

What software you use, depends on the potential for Return on Investment.

By that I mean, if you are going to build a single pair of $200 speakers, it doesn't make much sense to invest $1000 in software and hardware to test it. On the other hand, if you anticipate several speaker projects and the software serving you over an extended period of time and over numerous projects, then perhaps a bit more money invested is worth it.

REW (Room EQ Wizard) is first and foremost FREE. It is a very sophisticated program and does a lot more than Room Frequency Plots. There are Videos on YouTube demonstrating how to calibrate and use REW. They are certainly worth a look. It really doesn't look like that complicated a program to use.

However you will need a Calibration Level Microphone and perhaps a audio mixer. Though those don't have to be all that expensive, and the software is free.

REW - Room EQ Wizard Room Acoustics Software

True Audio RTA is a decent program at a very modest price, and with several options -

True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software

TrueRTA Audio Spectrum Analyzer Software

TrueRTA Audio Spectrum Analyzer Software - Comparison Guide

Again, it gets down to how much budget is justified. If you can justify hundreds of dollars then -

Dayton Audio OmniMic V2 Precision Audio Measurement System 390-792

Dayton Audio DATS Dayton Audio Test System 390-806

Keep in mind, the price of software can literally run into the thousands.

If you want or need design software, there are options here too, from free (WinISD) to moderate to expensive to REALLY expensive -

About WinSpeakerz: Loudspeaker Design software for Windows

BassBox 6 Pro/X-Over 3 Pro Software Set CD-ROM 500-927

SoundEasy Loudspeaker Design Software USB Key 500-912

LinearTeam- WinISD

LinearTeam- WinISD Pro

The question that must first be answered is - How far do you want to take it and how much money can be reasonably justified?

Probably the lowest cost, yet highly effective, method for testing is a mic and the REW software.

Though there are other options as well.

Steve/bluewizard

Pano · 2013-10-06 7:12 pm

From your plovts it doesn't look like the top end would sound edgy. Maybe it's that peak a ~650Hz and dip aboe it? Something not right going in there. Do you know where the crossover points are set? With a sweep you can also look at distortion, which might be giving you the edge your hear.

RamJBL · 2013-10-06 7:26 pm

Pano said:
From your plovts it doesn't look like the top end would sound edgy. Maybe it's that peak a ~650Hz and dip aboe it? Something not right going in there. Do you know where the crossover points are set? With a sweep you can also look at distortion, which might be giving you the edge your hear.

That could be. I am suspicion of that too.

I haven't design the xo myself. I think measuring the drivers individually should help find out the points. So, I think I should just disconnect all other drivers and do the gated measurement. Is that correct?

For distortion, do you mean THD? I can click on that after the measurements (THD, Phase plot...).

RamJBL · 2013-10-06 7:28 pm

To measure the tweeter or midrange, how close should the mic be located to them?

Pano · 2013-10-06 8:17 pm

You can be 1 meter (39 inches) away. That's standard.

If you click on the distortion drop down you will able to see each harmonic. H2, H3, H4, etc. But start with THD

a.wayne · 2013-10-06 9:11 pm

Pano said:
From your plovts it doesn't look like the top end would sound edgy. Maybe it's that peak a ~650Hz and dip aboe it? Something not right going in there. Do you know where the crossover points are set? With a sweep you can also look at distortion, which might be giving you the edge your hear.

I don't believe his setup is accurate down to 650hz , it looks like room reflections to me and he never gave his reflective path distance, of his gated setup.

Pano · 2013-10-06 9:13 pm

True, might be bounce that we see.

a.wayne · 2013-10-06 9:13 pm

RamJBL said:
To measure the tweeter or midrange, how close should the mic be located to them?

Whats your reflective path distance and could you post up impedance magnitude and phase ...

RamJBL · 2013-10-06 9:50 pm

a.wayne said:
I don't believe his setup is accurate down to 650hz , it looks like room reflections to me and he never gave his reflective path distance, of his gated setup.

How can I do that? I tried to adjust the gate in the pulse-response... Sorry for the dumb questions. I am new to this software and these measurements.

Pano · 2013-10-06 10:13 pm

What is good to know is the distance of the path a major reflection might take from speaker to microphone. That reflection will arrive later than the direct sound, of course, and can cause nulls. Often the nearest large surface is the floor. For example, at my listen position the floor bounces causes a null at about 350Hz.

Look at your set up. How far is the mic from the speaker? How far is the mic from the nearest reflection point?

RamJBL · 2013-10-07 1:28 am

Pano said:
What is good to know is the distance of the path a major reflection might take from speaker to microphone. That reflection will arrive later than the direct sound, of course, and can cause nulls. Often the nearest large surface is the floor. For example, at my listen position the floor bounces causes a null at about 350Hz.

Look at your set up. How far is the mic from the speaker? How far is the mic from the nearest reflection point?

The mic is 39 inch away from the speaker and at the midrange-driver level. The mic is ~69 inch away from the wall behind the speaker. I have attached a photo.

a.wayne · 2013-10-07 1:49 am

Place the speaker on the table where you have the mic now or best out into the middle of the room, get a mic stand for the mic . Next measure the distance from tweeter to floor , double it , this is your nearest reflective path , i would also place mic at tweeter level directly facing tweeter .

With such a setup , you will have ok accuracy down to 800 hz

RamJBL · 2013-10-07 2:04 am

The speaker is too heavy. I think it's 60 kg or something. It is also on spikes. I will try, but I don't think I am strong enough to put them on the table.

I can move the speaker to middle of the room and make a measurement. I have a thick insulation (you can see it the photo, in the back of the speaker). I can place it front of the speaker.

Tomorrow I am planning to give the tweeters to a pro to give their titanium domes (052Ti) a coating. I am very happy with the sound of these speakers. The only "minor" issue is that they are a little bit sharp in high region.

Measuring the SPL of loudspeaker at home.

Administrator

Administrator

Attachments

Disabled Account

Disabled Account

Administrator

Member

Disabled Account

Member

Administrator

Disabled Account

Disabled Account

Administrator

Member

Administrator

Member

Disabled Account

Administrator

Disabled Account

Attachments

Member

Disabled Account