MTM RS180 Seas H1212 tester finished\Too revealing? (threads merged)

[AJINFLA]

The cheap, immediate band aid would be rotating (no joke) you standard treble knob on your pre -4 to -8db, watching the effect on the RTA. That should flatten out the sizzle a bit. Adjust by ear if necessary.
As Jon suggests, the hash from the mids will still be coming through, but it won't be shown clearly in the summed response.
The real fix, if you are to continue measuring inside, is to download ARTA (free) and obtain gated individual driver magnitude and phase response as mounted in the baffle. Then use the FRD tools to (re)design the XO. Tweak. Listen. Measure on and off axis. Listen. Tweak more if necessary. Welcome to the (real) world of building your own loudspeakers. Enjoy.

cheers,

AJ

[TurboFC3S]

I disagree. That's a huge rise at the top end that should not be there.

Yea, if you look at the scale that's about almost a 10db rise ...

[JonMarsh]

The cheap, immediate band aid would be rotating (no joke) you standard treble knob on your pre -4 to -8db, watching the effect on the RTA. That should flatten out the sizzle a bit. Adjust by ear if necessary.
As Jon suggests, the hash from the mids will still be coming through, but it won't be shown clearly in the summed response.
The real fix, if you are to continue measuring inside, is to download ARTA (free) and obtain gated individual driver magnitude and phase response as mounted in the baffle. Then use the FRD tools to (re)design the XO. Tweak. Listen. Measure on and off axis. Listen. Tweak more if necessary. Welcome to the (real) world of building your own loudspeakers. Enjoy.

cheers,

AJ

Good suggestions, AJ.

Maybe you can help me, too; I've never been able to find the tone controls on my Ayre preamp..... :W

[---k---]

Maybe you can help me, too; I've never been able to find the tone controls on my Ayre preamp..... :W

Jon, even the junk at RS has tone controls. Maybe it is about time you invested in some decent gear.

[JonMarsh]

Jon, even the junk at RS has tone controls. Maybe it is about time you invested in some decent gear.

You could have a point, there, what with my current hifi gear, vintage motorcycles and the reputation I've got from that Delorean thingie, I'm a bit behind the times.

Probably ThomasW would tell me I need to get some sort of digital EQ, particularly if I want to get my Denon turntable with Linn Itok arm back from him and get serious about some 180 gram vinyl. :W

[4thSeason]

I have had enough. I came here to learn, enjoy the company, to get constructive advice and to perhaps add something to the community if I could.


When we start making accusations of fantasy land and incompetence, I will , as opposed to lowering myself to certain others individuals mentality or arrogance will find enjoyment elsewhere. If my questions are so incomprehensible perhaps I should be banned. I mean hey we don't want stupid people on here sullying our board- they just make us look dumb.

I must say AJ your arrogance is impressive, it really is. But I'm off to fantasy land to endeavor in some good old fashioned incompetence. It's people like you who make this world truly great, really. I am blessed to read your writing.

[Dennis H]

4th Season,

Thanks for the graph. I think you may have overreacted a bit. I didn't see any personal insults aimed at you. I think AJ was talking about the designer, not you, but it's easy to misunderstand something typed in a forum. We all appreciate your measurements. It would be helpful if you could expand the graph so it shows something like 50dB total range (say 30-80) and uses a bit less smoothing, say 1/12 octave. That would make it easier to see what's going on.

[TurboFC3S]

When we start making accusations of fantasy land and incompetence, I will , as opposed to lowering myself to certain others individuals mentality or arrogance will find enjoyment elsewhere. If my questions are so incomprehensible perhaps I should be banned. I mean hey we don't want stupid people on here sullying our board- they just make us look dumb.

I must say AJ your arrogance is impressive, it really is. But I'm off to fantasy land to endeavor in some good old fashioned incompetence. It's people like you who make this world truly great, really. I am blessed to read your writing.

Awesome, another overcompensating cyber-bully gets what he deserves! :nutkick: :dancenana:

[dlneubec]

Anyone venture to guess that 4thseason is directly related to Jay_WJ, back for another attempt to impress? Maybe reincarnation is real, at least on the internet.

[probillygun]

4th Season,

Thanks for the graph. I think you may have overreacted a bit. I didn't see any personal insults aimed at you. I think AJ was talking about the designer, not you, but it's easy to misunderstand something typed in a forum. We all appreciate your measurements. It would be helpful if you could expand the graph so it shows something like 50dB total range (say 30-80) and uses a bit less smoothing, say 1/12 octave. That would make it easier to see what's going on.

Dennis, 4th season IS the designer. That's why he is taking offense, and I can certainly understand why.

[JonMarsh]

Anyone venture to guess that 4thseason is directly related to Jay_WJ, back for another attempt to impress? Maybe reincarnation is real, at least on the internet.

Oh, it's very real, though I have no idea in this particular case.

It's an interesting thing, working in an international company, between German and American engineers you have have very frank discussions with disagreement about technical issues and rarely does anyone take it personally, but with some of our Asian colleagues in our own company, more sensitivity is needed.

In this case, I see (as a moderator) no personal attacks, just a frank discussion of the limitations of the measurement and to what degree you can make any realistic assessment of the sound quality based on those measurements.

We don't want anyone run off, but there is a lot of science to this hobby.

Certainly one must take baby steps before playing in the minor leagues and then moving up to something more serious, but it is best NOT to confuse an attempt at constructive criticism (which I've certainly received around here, too) with a personal attack. In fact there's nothing AT ALL resembling a personal attack in AJ's comments, just some frank advice.

Some of us are new to this hobby, some have been doing it almost 40 years. We're not making it up when we draw attention to the fact that certain development protocols are needed to avoid typical beginner's problems- there's a reason we point out these things, many of us (at least myself) have made those same mistakes in the past.

There's a reason I've done over 50 speaker projects. Generally, there's not too many of them I'd want to post here... :W even if most of them have been musically satisfying- at least for a while. Wasn't until the late 70's I'd say I really started to get the hang of it, and unfortunately there's a lot of things I've done since then that were certainly "Different", but NOT necessarily "better".

Live and learn....

[AJINFLA]

Keep in mind that the XO was designed incompetently in fantasy land. No measurements

I was clearly referring to the designer of the XO, not you. My apologies if you feel personally insulted by this. I take it WJ a close friend or perhaps a relative, as suggested.

I came here to learn, enjoy the company, to get constructive advice and to perhaps add something to the community if I could.

This is a great place to learn. If WJ had stuck around long enough, you probably wouldn't have been in need of a complete revision of your XO.
Clearly, you are not satisfied his design.

cheers,

AJ

[Dennis H]

Dennis, 4th season IS the designer. That's why he is taking offense, and I can certainly understand why.

Well, if 4th Season is really an alter-ego for Jay, we didn't know that. Some people can't handle constructive criticism; such is life. He started this thread about what could be wrong with his speakers so he obviously knows there is a problem his sims didn't show. Unfortunately, he didn't provide enough information for us to get to the bottom of it. The posted measurement was a good start but not enough to nail it down. Sorry if he got offended and went away. I think we were getting closer to understanding what is going on......

[4thSeason]

No not a close friend. Acquaintance perhaps. Many are so quick to bash and embarrass here. The truth is I consider failures greater learning experiences than victories. It's not what you said but how you said it. Yes he took a Zaph design and modded it. I took my FRD and ZMA files and simmed and built it so -I DO- take offense in so much as I had much more vested in this than he did. I honestly don't know where I got those FRD or impedance files but I do remember this they were tested in that PE baffle in this config. I didn't just trace the factory spec sheets. No one ever asked that.
At the time I started this project I had no test equipment or even a Jasper jig for that matter I just started reading, buying, and learning on the fly. I have never complained that my speakers were terrible just that what I really need is direction not criticism ...Just because I didn't test this setup doesn't mean it had never been done or documented.

It is said that a little knowledge is dangerous and I am defiantly in this phase. Uncomfortable discussing intricacies of design and testing. But I will learn more and the truth is these speakers sound good most of the time. I can sincerely say that I have never ever heard a speaker that cost $250 dollars a pair that can hold a candle to the way these sound albeit sometimes problematic.
In saying that I am going to try some things in the coming days. Some here have tons of time to dedicate to this passion. I however, have been swamped trying to get tennants in my vacancies. I am a single father, I work full time for the Federal Govt. I am soldier and I'm buying a Pizza shop and 23 more apartments as we speak. I try hard to find time here because I love music and I love learning new things. It just feels like somtimes we are assumed to know certain things easy to some, but foriegn to us newbie builders.

Blessings

Bri

P.S. No alter ego here my last name is Winter thus the 4th season. I do like costructive advice but not when it comes out in a condescending tone

[Dennis H]

Okay, thanks for the post Bri. I get it now. Jay helped you with the design but it wasn't 'his' design. Stick around. Once everyone cools down, we'll figure out what's going on with your speaker and hopefully help you make it sound better.

[AJINFLA]

Well, I appear to be not alone in misunderstanding. I was under the impression that you built this loudspeaker, but the design of the XO was done by WJ.
We could go on and on about this point, or you could accept my apology that the slight was directed at Jay, not you - and post some further measurements so we might all learn something. I'll leave that choice up to you.

cheers,

AJ

[4thSeason]

Dennis I have cooled out abit and the truth is I have thick skin for joking but didn't feel that was the case, but thank you for saying what you did. I respect your opinion . I do want to do more here. If you asked someone close to me my OCD often times compells me to go way to hard at things somtimes. I am sure before I move to another hobby or passion I will destroy plenty of MDF.
It is like I said though somtimes on this board people say that you should just GET THINGS.
Jay emailed me this morning and said that I should test the speakers with individual drivers in them to confirm what the crossover is doing. My quandry is this if I remove a load from the crossover it should screw up impedance in a parallel circuit. I may try it though.
I downloaded ARTA but am not sure what differently. If someone could direct me as to how to do this bench test that we can show more specific problem areas.

[4thSeason]

Okay I now understand that slight was not directed at me. I am not getting into trying to defend other people for whatever conflict others share. I accept and I will do my best to plod forward with this project. And BTW thanks for clarifying.

B

[Jed]

What questions do you have regarding ARTA. I could probably help you. Did you make a jig yet and what soundcard are you using?

[4thSeason]

What questions do you have regarding ARTA. I could probably help you. Did you make a jig yet and what soundcard are you using?

I am using my laptop with and Maudio Pre usb. Behringer ECM8000 mic. Jig. okay now I am feeling like I am missing somthing. Please advise.

Never mind I found the link to building a JIG for LIMP. Can do.

As to questions just direct me to where the instructions for what tests people want to see me run on ARTA and how to run the setup if necessary

Bri

[Jed]

As to questions just direct me to where the instructions for what tests people want to see me run on ARTA and how to run the setup if necessary

Bri

Ok, once you have the Jig setup, I'd like you to take some impedance measurements of the individual drivers in box. Then, once you get that far, we'll take it to the next step, which will be FR measurements on axis of the individual drivers. We can take a screen shot, trace the data with the SPL tracing tool, and with the FRD tools calculate mininum phase, import the files into Speaker workshop and create a crossover together. This would be a lot easier if you buy the ARTA software versus demo mode because you could save the files and bypass the need to use the FRD tools etc, but it'll work either way.

Jed

[Dennis H]

Ok, once you have the Jig setup, I'd like you to take some impedance measurements of the individual drivers in box. Then, once you get that far, we'll take it to the next step, which will be FR measurements on axis of the individual drivers. We can take a screen shot, trace the data with the SPL tracing tool, and with the FRD tools calculate mininum phase, import the files into Speaker workshop and create a crossover together. This would be a lot easier if you buy the ARTA software versus demo mode because you could save the files and bypass the need to use the FRD tools etc, but it'll work either way.

Jed

Way cool, Jed. :T This might be worth a new thread. If you guys keep it here on the forum rather than going offline, this could turn into a nice Crossover Design 301 tutorial.

[PoorboyMike]

Way cool, Jed. :T This might be worth a new thread. If you guys keep it here on the forum rather than going offline, this could turn into a nice Crossover Design 301 tutorial.

I agree. I would be very interested in following a thread like this! ;x(

[cjd]

Though it is a different headache, it may be worth checking out Speaker Workshop. I found the plain wire "jig" setup to be quite simple to assemble and work with. That will gain you the ability to measure the various drivers in position with perfect relative phase (i.e. no need for the few extra sim steps).

I have to go through setup again on this since I moved things to a new computer. Way "fun".

C

[4thSeason]

Ok, once you have the Jig setup, I'd like you to take some impedance measurements of the individual drivers in box. Then, once you get that far, we'll take it to the next step, which will be FR measurements on axis of the individual drivers. We can take a screen shot, trace the data with the SPL tracing tool, and with the FRD tools calculate mininum phase, import the files into Speaker workshop and create a crossover together. This would be a lot easier if you buy the ARTA software versus demo mode because you could save the files and bypass the need to use the FRD tools etc, but it'll work either way.

Jed

Okay Jed I will be looking into both the ARTA and SW jig. But before we shift gears and redesign this crossover(which I'm not saying I won't) I would like to get to the heart of my issues via all testing methods short of you guys coming over and listening to my gear, but that said I want to ferret out what we have now before throwing it away. I can only learn from the process of testing and posting results.
It was mentioned that I should do individual driver test with crossover to see what my curve looked like in the breakup region. I am wondering if I remove my tweeter from the circuit I need to add a resistor.
If everyone wants to see a new thread I will also do individual tests as you mention while I rip these apart.
I understand you said we could design new networks together should we discuss goals? I would think many hear think it would be prudent just to build the Modula network.

[cjd]

No problem pulling the tweeter. Impedance of the network approaches infinity (or something like that) out of its range.

FWIW, measuring loudspeakers is probably the most technically miserable and difficult process, because you can't share that work. You can show a network, a response, even data files, and get help. But measuring... ugh. I hate it.

C

[Jed]

Though it is a different headache, it may be worth checking out Speaker Workshop. I found the plain wire "jig" setup to be quite simple to assemble and work with. That will gain you the ability to measure the various drivers in position with perfect relative phase (i.e. no need for the few extra sim steps).



C

Yeah I like this suggestion better, actually. It would be good practice to use the FRD tools though.

Jed

[Jed]

I understand you said we could design new networks together should we discuss goals?

The goal is to design a speaker after taking your own measurements. It's not about the end product. Can you tell I'm a HS teacher? :B

[Jed]

But measuring... ugh. I hate it.

C

I had the same sentiments when I was using SW. Now with ARTA and JustMLS it is a snap. . . well at least a lot more intuitive.

[Dennis H]

Dumb software questions alert.

How does ARTA handle phase? Could you, say, measure all the drivers of an MTM on the tweeter axis with ARTA, plug the magnitude and phase info into SW with the drivers located at 0,0,0 as far as SW is concerned and get accurate phase summing for the XO? Assuming all that works, where would you subtract the time of flight (distance from mic to baffle), in ARTA or in SW?

Edit: ARTA really looks like a bargain, thus the questions. Sort of a poor-man's Praxis -- 90% of the stuff you really care about for 10% of the price.

[Jed]

Dumb software questions alert.

How does ARTA handle phase? Could you, say, measure all the drivers of an MTM on the tweeter axis with ARTA, plug the magnitude and phase info into SW with the drivers located at 0,0,0 as far as SW is concerned and get accurate phase summing for the XO? Assuming all that works, where would you subtract the time of flight (distance from mic to baffle), in ARTA or in SW?

Edit: ARTA really looks like a bargain, thus the questions. Sort of a poor-man's Praxis -- 90% of the stuff you really care about for 10% of the price.

I'm running ARTA in demo mode and have taken measurements on axis only with the drivers all together with crossovers in place. Basically to cross reference my outcomes in JustMLS to verify accuracy, etc. That said, there are limitations with SW in regards to phase calculations so I would review www.claudionegro.com (SW phase tab- in particular) and take the measurements as outlined on axis, then use minimum phase (FRC), and offset the drivers acoustic center in SW to reflect the distance variations.

Here is what I like about LSPCAD and JustMLS, it does this work for you without having to use minimum phase data. Just type in the driver coordinates and you are good to go after measuring on axis. Dennis, I thought you were using LSPCAD?

[Dennis H]

Hmmm, that's a bit discouraging. I was hoping ARTA would do 'real' phase data that SW could use if you didn't move the mic from driver to driver. There's really no way to accurately know the acoustic center of a driver so you get into simulationland if you have to estimate it as opposed to using real phase measurements.

JustMLS is nice but swept-sine measurements are better in theory. But you gotta have the phase data to make it worthwhile.

[Jed]

Hmmm, that's a bit discouraging. I was hoping ARTA would do 'real' phase data that SW could use if you didn't move the mic from driver to driver. There's really no way to accurately know the acoustic center of a driver so you get into simulationland if you have to estimate it as opposed to using real phase measurements.

I think SW is the real limitation. That said, I can't tell you if ARTA will generate phase that SW will recognize with a fixed mic location. Haven't tried it and probably won't unless for some reason LSPcad isn't doing what I need it to-NOT likely.

Why not just use SW to do those measurements with a fixed mic location? That's how Roman does it so I know it works.

[Dennis H]

I think SW is the real limitation. That said, I can't tell you if ARTA will generate phase that SW will recognize with a fixed mic location. Haven't tried it and probably won't unless for some reason LSPcad isn't doing what I need it to-NOT likely.

Why not just use SW to do those measurements with a fixed mic location? That's how Roman does it so I know it works.

Okay, cool. Back on topic, we need a 'real' measurement method for 4th Season to use. I've got a feeling that the phase/AC thing is one of the things that bit Jay in his sims so avoiding Hilbert transforms would be a good thing for this project.

[Jed]

Okay, cool. Back on topic, we need a 'real' measurement method for 4th Season to use. I've got a feeling that the phase/AC thing is one of the things that bit Jay in his sims so avoiding Hilbert transforms would be a good thing for this project.

Fixed mic location in speakerworkshop will work-it'll do real phase and it looks like ARTA will too after reading this in the manual. Besides, I don't get the impression 4th Season wants to buy ARTA when he can just use SW for free- even if it is a pain. CJD mentioned he should take his measurements in speakerworkshop, and I am changing my tune and agree with this suggestion, unless he wants to get to know how to use the FRD tools, which is a great learning experience. To take measurements in SW follow Roman's tutorial at www.rjbaudio.com. Just go to his links page and you'll find his tutorials on a variety of subjects. No need to reinvent the wheel. Also, take a look at SW page on Claudionegros page. He has a good tutorial as well. www.claudionegro.com. I like Dennis's recommendation of the fixed mic location if using SW, even though Claudio mentions there are some limitations using this method, it'll get him close enough!

From the ARTA manual about phase:

Besides Magnitude and Phase plots user can view Minimum Phase plot and Group Delay plot. Manipulations with frequency response plotting modes are handled with menu View. It has following
pop-up items:
Magnitude - shows the frequency response magnitude
Magn+Phase - shows the frequency response magnitude and phase
Phase - shows the frequency response phase
Group delay - shows the group delay
Minimum phase - check to show the system minimum phase
Unwrap Phase - check to show the unwrapped phase
Excess phase - check to show excess phase
Excess group delay - check to show the excess group delay
Sound pressure units
dB re 20uPa/1V - unit for pressure level in acoustical standards
dB re 20uPa/2.83V - usual unit for the loudspeaker sensitivity
dB re 1Pa/1V - unit for pressure level in ITU_T recommendations
Setup - activates the dialog box for plot margins setup
Time-Bandwidth Requirement - if checked, curves are plotted only for frequencies where timebandwidth product is larger than 1.

A simple definition of minimal phase is: A system phase characteristics for which the equivalent system with the same magnitude characteristics and a minimal phase changes can be realized (over all requencies). The difference between the phase and the minimal phase characteristics is usually called
excess phase. Mathematically, the minimal phase can be estimated from the magnitude of the frequency response using the Hilbert transform. The ARTA, as well as other similar programs, use the DFT to calculate the Hilbert transform. It introduces periodicity in the estimation of the minimal phase and gives the result that is close to the true minimal phase only at frequencies below fs/4.

[4thSeason]

Though it is a different headache, it may be worth checking out Speaker Workshop. I found the plain wire "jig" setup to be quite simple to assemble and work with. That will gain you the ability to measure the various drivers in position with perfect relative phase (i.e. no need for the few extra sim steps).

I have to go through setup again on this since I moved things to a new computer. Way "fun".

C

Help I thought I found a resource for a simple jig but now I can't seem to locate could someone let me know if they have specs or design for one.

Bri

[dlneubec]

I don't know how Speaker Workshop does it, but this is the one I put together for SoundEasy.

[Dave Bullet]

4th season,

I don't know if this has been suggested yet... but does the forward sound on the worst recordings stay with the same speaker? Flick the amp into mono if possible. Is one speaker or the other more forward?

This would indicate driver or more likely crossover anomalies.

The problem with the 14uH inductor. It's such a small value and a precision notch that unless you measured them yourself, the notch could be off. ie. with a 10% tolerance the inductor could be 12.6uH in one speaker and 15.6uH in the other.

I don't have time to sim the effect of this right now, but something worth looking at.

david.

[Jed]

Help I thought I found a resource for a simple jig but now I can't seem to locate could someone let me know if they have specs or design for one.

Bri

www.claudionegro.com has 2 jigs documented