60 Degree DIY Mid Hi - AKA PM60

[Don J Davis]

Re: 60 Degree DIY Mid Hi

A lot of the people I see using Smaart don’t really understand exactly what they are measuring.

If you use an FFT with a time window that’s big enough to capture the low frequencies you are usually capturing other stuff you don’t want that mucks up your measurement.

There are basically two solutions – measure it in an anechoic chamber – or measure it a long way away from any boundary’s (12ft in the air or more) where the mic is relatively close (6 ft) to the speaker.

Note: this is a mid-Hi box operating from 100Hz up (100Hz wave length = 11.15ft, 10ms per cycle). For low frequency you can place the mic on the ground.

As a practical solution your setup with the ground sloping away looks great.

Would there be interest/benefit in a new thread dealing with testing and tuning the DIY's? I've discussed it with Peter and he's in favor. I've been working on some FIR and IIR settings and have lots of questions for the more experienced Smaart/SIM users here.

Would that thread belong in the DIY Forum? Maybe Bennett can answer that.

What say you guys?

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Hi Don,

I would like to see two things-

- A bit of a data base of settings for the (DIY) double 12 stick horn for people to try and;
- A tread on how to measure and created suitable settings for any DIY.

Creating settings if you happen to have a large anechoic chamber is relatively easy but for those building DIY projects it can be tricky. It has certainly be the most difficult part of this project for me.

There are a whole bunch of topics:

- How and where to measure
- Phase alignment through the crossover
- What is a suitable crossover point
- The use of out of band filters to control resonances and phase
- The use a target curves for normal in room EQ- ing.
- etc

There have been a few recent articles about some of these topics. There is a good AES publicationJuly / August 2015 by Toole, and there is an article on this board at the moment by Raimonds Shuruls https://soundforums.net/content/3636-Equalizing-loudspeakers

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

Hi Don,
I would like to see two things-

-A bit of a data base of settings for the (DIY) double 12 stick horn for people to try and;
-A thread on how to measure and created suitable settings for any DIY.

Creating settings if you happen to have a large anechoic chamber is relatively easy but for those building DIY projects it can be tricky. It has certainly be the most difficult part of this project for me.

There are a whole bunch of topics:

-How and where to measure
-Phase alignment through the crossover
-What is a suitable crossover point
-The use of out of band filters to control resonances and phase
-The use a target curves for normal in room EQ- ing.
-etc

There have been a few recent articles about some of these topics. There is a good AES publicationJuly / August 2015 by Toole, and there is an article on this board at the moment by Raimonds Shuruls URL="https://soundforums.net/content/3636-Equalizing-loudspeakers"https://soundforums.net/content/3636-Equalizing-loudspeakers

Peter,
Excellent! I for one have a lot to learn about this. And since I know I'll be building more DIY projects I want to learn as much as possible.

On the database, what would be the best way/format to do that? Excel spreadsheets? I'd be happy to post all my processor settings and help keep the DB up to date with others.

Also, I'll be using the 90 deg boxes this evening at the chapel. I plan getting there early to do some room measurements using both the Driverack 480 and the Lake Contour for processing as well as AB'ing the processors. I'll try and take some screen shots.

And, that article by Raimonds is excellent.

Here is the link for the AES article you mentioned. I haven't had time to read it yet.
http://www.aes.org/e-lib/browse.cfm?elib=17839

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

More testing on the DIYs, at least I had room for the pizza.

As I knew beforehand, building the box is the easy part, coming up with meaningful settings is much more difficult.

This is just some testing I did in my garage over the weekend using low levels of pink. I'm mainly trying to get a handle on phase through the crossovers.

One thing I did find out was that the reference mic I have been using had been dropped a few too many times and was no longer registering HFs well. So much for my earlier settings...

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Peter,
Excellent! I for one have a lot to learn about this. And since I know I'll be building more DIY projects I want to learn as much as possible.

On the database, what would be the best way/format to do that? Excel spreadsheets? I'd be happy to post all my processor settings and help keep the DB up to date with others.

Also, I'll be using the 90 deg boxes this evening at the chapel. I plan getting there early to do some room measurements using both the Driverack 480 and the Lake Contour for processing as well as AB'ing the processors. I'll try and take some screen shots.

And, that article by Raimonds is excellent.

Here is the link for the AES article you mentioned. I haven't had time to read it yet.
http://www.aes.org/e-lib/browse.cfm?elib=17839

Yes - the settings are the hard bit, and because the box is so clear and FIR settings sound so real any minor changes / errors stands out. It’seasier to get the IIR settings nice than the FIR settings, but once you get aset if FIR settings right, they are spectacular.

The low frequency end is tricky. It’s difficult to avoid the influence of nearby boundaries. If you are not careful you will end up cutting and boosting things you should not. When you measure the box stacked on top of a sub expect the low frequencies to measure about 6 dB more than the HF because of the boundary effect. There will also be some cancellation notches if the microphone is not on the ground; and if it’s on the ground you can’t measure the HF.

The best results I have achieved have been by measuring thebox at about 4m with the mic (and box) about 4m high (or more) and away from any boundaries. Then listen with music and your voice, make sure it sounds right with both. I typically use 1/6 octave smoothing but I also use 1 octave smoothing to ensure the energy across the spectrum is flat. Your hearing is will notice if the power response is not smooth in the coverage area. I don’t worry too much about things above 16KHz.

Sometimes Smaart / Systune will tell you that there is a dip in the response, but the box will sound better without the apparent correction EQ …. so listen carefully. I often ask someone else which sounds better.

After you have been listening for a while your brain seems to correct for some of the errors so you need to take a break and come back andlisten with fresh ears…

I used 60 degree boxes this weekend for a loud outdoor rock band - 2 per side on some double 18 subs. At 150 feet you could feel the snare drum, toms and kick drum hitting you in the chest! Not bad for a couple of speakers designed to be stick mounted.

It was the first time the bands engineer had used the boxes. He had a big smile on his face and was shaking his head in disbelief at the volume and clarity he was achieving.

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

I was able to finish the 2nd set of boxes this past weekend. This set will have the 60 deg horns all the time and will be used when I need to deploy 2 a side for larger events.
I haven't had time to set up the proper testing rig per Peter's suggestions but I did some quick work on the processing with the box on its back pointing up in my back yard. I was mostly looking at phase and did a quick pass through on the EQ.
I started with Peter's Lake settings and modified them to fit my boxes. His all-pass filters where spot on. The delays where slightly different. Here is a capture of the trace.
I expect things will change when I can fly these and do some proper testing. And I know it can be better!

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

I was able to finish the 2nd set of boxes this past weekend. This set will have the 60 deg horns all the time and will be used when I need to deploy 2 a side for larger events.
I haven't had time to set up the proper testing rig per Peter's suggestions but I did some quick work on the processing with the box on its back pointing up in my back yard. I was mostly looking at phase and did a quick pass through on the EQ.
I started with Peter's Lake settings and modified them to fit my boxes. His all-pass filters where spot on. The delays where slightly different. Here is a capture of the trace.
I expect things will change when I can fly these and do some proper testing. And I know it can be better!

...now add a 24 dB LR high pass filter at about 90Hz to 100Hz and have a look at what it does to the phase between 100Hz and 1KHz ~~:smile:

If you are too close (4ft) you will not get correct delay between the lows and horn / mids ... also the phase response around 16 KHz will be influenced by the phase response of the signal change including the amplifier.

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

...now add a 24 dB LR high pass filter at about 90Hz to 100Hz and have a look at what it does to the phase between 100Hz and 1KHz ~~:smile:

Peter,
I already have the HP engaged and set at 100Hz. Is there something else I should try to flatten the phase a bit? Attached is a screen shot of the controller settings for the Mids.

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Peter,
I already have the HP engaged and set at 100Hz. Is there something else I should try to flatten the phase a bit? Attached is a screen shot of the controller settings for the Mids.

The plot above does not look like the 100Hz HP filter was in ... if it was, it should have been 6 dB down at 100Hz.

What polarity is the MID / HF / VHF - with all pass filters you have shown above, I think they should all be -ve and the sub +ve.

 

[Raimonds Skuruls]

Re: 60 Degree DIY Mid Hi

Hi Don,

I would like to see two things-

- A bit of a data base of settings for the (DIY) double 12 stick horn for people to try and;
- A tread on how to measure and created suitable settings for any DIY.

Creating settings if you happen to have a large anechoic chamber is relatively easy but for those building DIY projects it can be tricky. It has certainly be the most difficult part of this project for me.

There are a whole bunch of topics:

- How and where to measure
- Phase alignment through the crossover
- What is a suitable crossover point
- The use of out of band filters to control resonances and phase
- The use a target curves for normal in room EQ- ing.
- etc

There have been a few recent articles about some of these topics. There is a good AES publicationJuly / August 2015 by Toole, and there is an article on this board at the moment by Raimonds Skuruls https://soundforums.net/content/3636-Equalizing-loudspeakers

Hello friends

The Dr. Toile’s article raised interest to write comments.
Please take a look!

http://aplaudio.com/downloads/Reading_Dr_Toole.pdf

https://soundforums.net/content/379...-and-Calibration-of-Sound-Reproducing-Systems

And let’s continue discussion.

BR,

Raimonds

 

[Mark Wilkinson]

Re: 60 Degree DIY Mid Hi

Hey all, hey Peter, hey Don !
Sorry to 'disappear' for a while.....new fiancee, road trip meeting her family, busted ass getting thrown from horse...all kinds of lame excuses lol

Anyway, really appreciate and want to join in on the testing and tuning ideas outlined above, especially now that I can lift crap again...

And glad to hear the DIY's are working well splayed together...

I've had I chance to listen to a number of smaller systems while traveling around, and I have to say the DIY60 is still the cleanest most alive sound I've encountered.
I know this is just auditory memory and personal preference talking, but really....the dang DIY ROCKS!!

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Hey all, hey Peter, hey Don !
Sorry to 'disappear' for a while.....new fiancee, road trip meeting her family, busted ass getting thrown from horse...all kinds of lame excuses lol

Anyway, really appreciate and want to join in on the testing and tuning ideas outlined above, especially now that I can lift crap again...

And glad to hear the DIY's are working well splayed together...

I've had I chance to listen to a number of smaller systems while traveling around, and I have to say the DIY60 is still the cleanest most alive sound I've encountered.
I know this is just auditory memory and personal preference talking, but really....the dang DIY ROCKS!!

I'm glad you are liking the DIY ... and if I do say so myself, I'm yet to find a speaker that sounds better, and one that goes anywhere near as loud for its size and weight.

What's happening in my part of the world as a result of some Facebook posts from people that have used the system; people are now requesting it over some expensive name brand boxes .... its starting to gain rider acceptance (on a small scale) :smug:

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Hello friends

The Dr. Toile’s article raised interest to write comments.
Please take a look!

http://aplaudio.com/downloads/Reading_Dr_Toole.pdf

https://soundforums.net/content/379...-and-Calibration-of-Sound-Reproducing-Systems

And let’s continue discussion.

BR,

Raimonds

Hi Raimonds,

One of the biggest issues for me has been trying to develop crossover and correction EQ settings for the DIY.

I wanted:

- Flat phase and amplitude response
- Excellent time domain behaviour
- Well controlled directivity especially in the horizontal plane.

Most people think that a flat amplitude response measured at the Front of House (FOH) mixing position is what is required. I often hear the results of this approach and it’s not good.
It does not allow for the effect boundaries have on the response, that we expect some HF roll off with distance, and that the measurement system does to match how we process and hear sound.

Toole’s paper discusses some of this and it seem to align with what I expected … i.e. Most people like 6-8 dB LF boost and a little HF roll off with distance; that’s what sounds natural. Flat (measured at FOH) will sound harsh … it is all of course dependant on the particular space you are in and your personal preference.

The conclusion I have come to is you should EQ the speaker flat as measured in an anechoic chamber … (if you can find one that’s big enough and goes low enough). You may need to make a few minor adjustments as a result of the directivity not being perfect so you still archive the best compromise in a "perfect" room (whatever that is).

In a real room there will be resonate modes with a reverberate field that is not consistent across the frequency spectrum. You will of course need to make system EQ adjustments to find the best compromise for each different room.

Unfortunately the best I have been able to do is fly the speaker so they are far enough away from any boundaries relative to the lowest frequency I’m trying to measure…. and listen.

I also took note of one of Earl Geddes papers where he suggests that horizontal pattern control was more important that the vertical pattern because of our hearing mechanism. He also suggested that a speaker's direct response and power response should match between 700Hz – 7000Hz … Although he is concerned with HiFi speakers I’m inclined to agree with his logic with respect to PA speakers..

https://www.youtube.com/watch?v=fE2nWVwFT9k

Check out the directivity curve on the 60 degree horn I used. Also note that at the crossover point the directive of the LF section (dipole) has an impact and should result in an even better DI.
http://www.eighteensound.it/PRODUCTS/Products/CatID/5/ProdID=180#.VkM-GmkbraQ

With respect to the time domain issues and identify resonances etc, your TDA program was most helpful (thank you). The fundament design criteria was to have all of the drivers operating in their piston range. This helps in eliminating many of the time domain problems that can occur. It also means that any lumps and bumps in the frequency response can be corrected perfectly with EQ without causing other issues.

 

[Raimonds Skuruls]

Re: 60 Degree DIY Mid Hi

Hi Peter,
Thanks for questions!
I am happy to serve your needs in any accuracy level you prefer.

Regarding crossover. For „serious”, pro use (when a work at full power is usual) a use of active FIR crossover must be considered. It means, you will have ability to eq the each particular band speaker to have almost ideal its performance on a crossover point.
For non pro use (speaker is working far from full power) a use of passive crossover should be considered because the risk, of getting crossover out of tune caused by a change of loudspeakers coil resistance, is much less.

Flat FR at FOH.
We should serve our guest performers as good as possible. It means that we must offer the work environment as good as possible to free them from any routine work in concert place. Most serious groups have all they song projects (mix of live and playback tracks and automation) prepared in studio. For most ideal case, the sound engineer of group should not hear difference between studio and concert sound.
I did that almost 17 years ago without use of any measurement technique.
It is much ease to do so with measurement tools available now.
And even by the group’s sound engineer himself, if rental company is just box movers and do not understand anything from sound.
As I wrote in comments to Dr. Toole`s paper, the 7dB fall from LF to HF is usual for studious and if you setup such curve in your concert place, the guest engineer will be very happy. For some cases more drastically curve of 9dB fall and 3...4...5 dB dip at 3.15kHz will help (it is called „mp1” in APL tools).
But first of all we must „see” haw it is (FR of your system) and then we can talk about flat or any other target.

What to do with „room”?
Nothing, if you are working with live sound in parallel – some sounds are reaching listeners directly from stage, some – by help of sound reinforcement system.
If everything is „plugged”, you can try to compensate HF losses and accumulation of LF. The ordinary parametric EQ is good for that. No look at some narrow band issues on FR if you are using ordinary RTA.
It is possible to do that based on measurement also. The paper „Equalizing loudspeakers” is describing some concepts.

Directivity.
It is very nice to have narrow vertical directivity pattern and wide and smooth horizontal. Narrow vertical pattern will give you much better acoustic relationship (direct sound / reverberant sound) and the clarity as a result.
But I would like to invite to tune up basic thing at first and than turn to directivity issues that are taking much serious efforts to introduce some changes.

It is a very nice but expensive idea to have all drivers working in a piston range. And this is connected to directivity such way that only small membrane (in relation to wavelength) is working in piston range and creating wide smooth directivity pattern.

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

I finally had a chance to use the 2 per side set up at an outdoor event yesterday. It was a inner city Thanksgiving dinner provided by some local churches.
The coverage was a bit of a stretch with a venue this wide but it was pretty acceptable considering.
The tops were powered by itech 4000's and there were 8 SRX718 subs across the front powered one sub per channel of itech 4000s. The tops easily out ran the subs.
IMO it sounded amazing. There were both live acts and a DJ. It is a very responsive system to mix on.
All in all I couldn't be more pleased with Peter's design!
I wasn't sure how to post a video on the forum so here its a Facebook link. Hope it works.
https://www.facebook.com/don.davis.522/videos/1060677433976416/
Also a screen shot of the set up.

 

[David Chrapla]

Re: 60 Degree DIY Mid Hi

Don did you use the Driverack or Lake for processing?

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

Don did you use the Driverack or Lake for processing?

Hi David,
I was using the Lake. I'm becoming more familiar with it and really am starting to like it.

 

[Don J Davis]

Re: 60 Degree DIY Mid Hi

Hello friends

The Dr. Toile’s article raised interest to write comments.
Please take a look!

http://aplaudio.com/downloads/Reading_Dr_Toole.pdf

https://soundforums.net/content/379...-and-Calibration-of-Sound-Reproducing-Systems

And let’s continue discussion.

BR,

Raimonds

Hi Raimonds,
I've read your article and Dr. Toole's and am trying to take it all in. I'm primarily doing live SR so I'm trying to make that application.

I downloaded the trail version of your TDA software to give it a try and see how it would help a DIYer like me on a project like this. I ran a test on one of the DIYs with a 60 deg horn in it. Not exactly sure what I'm looking at though. Here are some screen captures of the TDA, AFR and DFR plus the Smart trace from the same session. There are no subs used during this test.

 

[David Chrapla]

Re: 60 Degree DIY Mid Hi

Thanks Don. While I would love to have the Lake setup its not in my cards anytime soon. SO I will have to keep following and see what I can come up with/

 

[Peter Morris]

Re: 60 Degree DIY Mid Hi

Hi Raimonds,
I've read your article and Dr. Toole's and am trying to take it all in. I'm primarily doing live SR so I'm trying to make that application.

I downloaded the trail version of your TDA software to give it a try and see how it would help a DIYer like me on a project like this. I ran a test on one of the DIYs with a 60 deg horn in it. Not exactly sure what I'm looking at though. Here are some screen captures of the TDA, AFR and DFR plus the Smart trace from the same session. There are no subs used during this test.

Hi Don,

The "heat plot" is showing you the amplitude & time response against frequency.
You can see the time delay caused by the 100Hz IIR high pass filter as the response trace swings to the left around 100Hz.

You can also see other time problems and resonances. In this case because all the drivers are operating linearly and in their piston range, nearly all the time issues can be corrected with EQ provided it’s in the correct place. If things are linear, the amplitude, phase and time domain response are all mathematically related. This is not the case when things are non - linear.

The picture I posted compares your results with mine, and the perfect response on the far right. Note that the perfect response does not include a 100Hz hi pass filter.

Looking at your results this would be my best (first) guess. You also have to consider that you will get different results depending on where you measure – i.e. on axis and off axis.

+2 dB @ 12K – 14K BW 0.33

+ 1 dB @ 4K9 BW 0.33

-1.5 dB @ 3K9 BW 0.4

+ 1 dB @ 990 Hz BW 0.5

- 2 dB @ 600 Hz – 650 Hz BW 0.33 – This is around the crossover so there are three options, input EQ, Mid band EQ and Low band EQ. – My best guess is try it in the Low band EQ. You may need to increase the depth of some of the cuts or reduce some of the out of band boosts.

- 1 dB @ 380 Hz BW 0.5

It also needs a bit more of a boost around 80 Hz, it is rolling off too fast with 100Hz crossover.

There is also an issue around 190 Hz – may need a little dip around there as well.