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Yamaha NS-6490 improvement project

No. 5

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A couple questions to get started with: do you have any equipment to measure the impedance curves and acoustic response of the drivers? And what kind of budget do you want to keep this project around (including test equipment if you don't have any)?
 
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richardbruce

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No.

A modest investment. The crossovers are $25 for both. I'm looking for thin rockwool batting now but thinking no more than $25.

I don't have any fancy audio measuring equipment. This is a mostly shooting from the hip, and listening with the ears project.
 

No. 5

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Well test equipment don't need to be fancy, it just needs to give you useful data. Enthusiasts get told they need to spend $100 or more on a calibrated measurement microphone to EQ their subwoofers all the time when a free app on a smartphone will do the job just fine. For what you want to do, you can use the tools you have: I saw in those pictures on the other thread that you have a multimeter and I assume that you have a smartphone? With appropriate expectations, those could be put into service for your project here. Although for impedance measurement, I'd highly recommend a simple (and cheep!) jig if you have a computer because although a multimeter can be used, it has potential for errors.

I'll tell you from experience, shooting from the hip and listening often results in undesirable results. Case in point: you had mentioned some new crossover points that you wanted to try, but in order to select the right components to do that, you need to know what the driver's impedance is around the desired crossover frequency. Otherwise your crossover frequency will be somewhere else. On top of that, the impedance of all the components will interact with each other, so it really helps to have the right data to simulate the results.

This doesn't mean that you need a laboratory and to become proficient in simulating crossovers, or that you can't go by ear (and at least somewhat by the hip), it's just that the right tools help help get better results. And myself and others are willing to help.
 
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richardbruce

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Well test equipment don't need to be fancy, it just needs to give you useful data. Enthusiasts get told they need to spend $100 or more on a calibrated measurement microphone to EQ their subwoofers all the time when a free app on a smartphone will do the job just fine. For what you want to do, you can use the tools you have: I saw in those pictures on the other thread that you have a multimeter and I assume that you have a smartphone? With appropriate expectations, those could be put into service for your project here. Although for impedance measurement, I'd highly recommend a simple (and cheep!) jig if you have a computer because although a multimeter can be used, it has potential for errors.

I'll tell you from experience, shooting from the hip and listening often results in undesirable results. Case in point: you had mentioned some new crossover points that you wanted to try, but in order to select the right components to do that, you need to know what the driver's impedance is around the desired crossover frequency. Otherwise your crossover frequency will be somewhere else. On top of that, the impedance of all the components will interact with each other, so it really helps to have the right data to simulate the results.

This doesn't mean that you need a laboratory and to become proficient in simulating crossovers, or that you can't go by ear (and at least somewhat by the hip), it's just that the right tools help help get better results. And myself and others are willing to help.
Thanks! Yours are the only really helpful comments, and I appreciate them.

Yes, I have an iPhone 11XR, microphones, an interface to convert their analog output to digital, and a laptop.
 

No. 5

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Thanks, just sharing some experience with a fellow enthusiast. :)

Now we're getting somewhere! Can you give me the make/models of your interface and mics? Hopefully the interface has two inputs, otherwise you won't be able to use it with an impedance jig. I'll go on a limb and guess that your mics are for vocals and instruments, if so, I'd be pretty hesitant to use them for this project, but we'll see. I'm not really an Apple guy, so I'm kinda blind when it comes to a good spectrum analyzer app for this project, this one looks like it might do what you need... but again, I haven't tried it.
 
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richardbruce

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Yes, all music equipment. PreSonus Audiobox USB (2 input), AKG Perception 200 condenser, EV N/D767a, Shure SM58 and SM57, Sennheiser 609 Silver.

Downloaded that app. What about a frequency generator app? There are many available in the App Store.
 

No. 5

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For a frequency generator, you should be able to go with about any, all you need is something that will do pure tones and pink or white noise. That being said, and I hate to change direction on you, but since you have a laptop and a nice interface, I'd recommend using that and a free software called REW. It has all the functionality (and more!) than you'll need for this project. That interface should work perfect for this purpose, both for measuring the drivers impedance and acoustic response.

For measuring impedance with a simple jig, REW's help files gives directions on that and how to use the software for that purpose. Basically, you'll need two 1/4" mono connectors (for the inputs), a 10 ohm resistor (as a sort of sensor), a stereo 1/4" connector (to use the headphone output to power the whole thing), and some wire to connect everything. A pair of alligator clips might make connecting to the driver's easier too, but it's not necessary. It's only a couple bucks in parts. And you can let me know if you need assistance, I find the schematic in the help file to be a little unclear. Edit: upon reflection, instead of buying raw connectors, you could just get some cables and cut them up (like one of these and one of these), you'll still need the resistor, of course.

For your microphones, the AKG or EV might work with suitably low expectations, if the data of them online is to be believed. I have actually measured a N/D767a before, and roughly comparing that particular one to my primarily measurement microphone, they tracked very closely between 400Hz and 3kHz. Below 400Hz there was a gentle roll-off, but that's fine for your purposes. Above 3kHz... they don't track, but the set up methods between two measurements aren't exactly apples to apples, so it's hard to say definitively. The EV appears to at least be pretty smooth, which is good. You'll definitely still need to use your ears, this will be something of a candle in the darkness so you're not shooting completely blind.
 
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richardbruce

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For a frequency generator, you should be able to go with about any, all you need is something that will do pure tones and pink or white noise. That being said, and I hate to change direction on you, but since you have a laptop and a nice interface, I'd recommend using that and a free software called REW. It has all the functionality (and more!) than you'll need for this project. That interface should work perfect for this purpose, both for measuring the drivers impedance and acoustic response.

For measuring impedance with a simple jig, REW's help files gives directions on that and how to use the software for that purpose. Basically, you'll need two 1/4" mono connectors (for the inputs), a 10 ohm resistor (as a sort of sensor), a stereo 1/4" connector (to use the headphone output to power the whole thing), and some wire to connect everything. A pair of alligator clips might make connecting to the driver's easier too, but it's not necessary. It's only a couple bucks in parts. And you can let me know if you need assistance, I find the schematic in the help file to be a little unclear. Edit: upon reflection, instead of buying raw connectors, you could just get some cables and cut them up (like one of these and one of these), you'll still need the resistor, of course.

For your microphones, the AKG or EV might work with suitably low expectations, if the data of them online is to be believed. I have actually measured a N/D767a before, and roughly comparing that particular one to my primarily measurement microphone, they tracked very closely between 400Hz and 3kHz. Below 400Hz there was a gentle roll-off, but that's fine for your purposes. Above 3kHz... they don't track, but the set up methods between two measurements aren't exactly apples to apples, so it's hard to say definitively. The EV appears to at least be pretty smooth, which is good. You'll definitely still need to use your ears, this will be something of a candle in the darkness so you're not shooting completely blind.
Ugh - I had to pay $8 for the app on my iPhone. But maybe it'll come in handy someday for... well, something.

I've got all kinds of cables, so that shouldn't be a problem.

What wattage resistor? One of those ceramic 10w ones?
 

No. 5

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Blast! I linked that one because it was supposedly free. But it may still be useful for this project since you won't be using a real measurement microphone, you can compare the results from your EV (or whatever mic you use) with the iPhone to hopefully get a clearer look at what's happening acoustically.

Oh good, that makes this a more affordable project.

1 watt will be sufficient, but if you have a 10 watt on hand it won't hurt anything. As long as it's non-inductive, you'll be fine. Also, I have to correct an error I made: the resistor in question needs to be 100 ohms, not 10. And it would be good to have a second one on hand to use to calibrate the jig. My bad, it's been awhile since I made one of these.
 
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richardbruce

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While I try to digest all (or even some) of what is REW, I plan to install the crossovers at the bottom of the cabinet. It's easier to just submit to gravity right off, and go with it, rather than attempt to secure the crossovers on the back inside wall of the cab.

Q: Can I just stuff the cabs with polyfill after installing the crossovers? I'm concerned about any heat that those big-a$$ resistors might generate. I hear polyfill is fire-resistant but... I hear a lot of things these days with my hearing aids ;-)
 

No. 5

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Yes, the bottom of the cabinet is a good place for the crossover.

Sure, and you can take a piece of thin carboard and make a little house over the top if you're concerned about it. Large, high wattage resistors should present less of a problem with that since it'll take a lot more power for them to heat up than small low wattage ones. Plus, if you don't listen very loud, that'll further reduce the potential issue.
 

alex-z

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Looking at the speaker measurement by amir, trying to fix these speakers is putting lipstick on a pig. Mineral wool is not going to fix the many resonances caused by the incredibly thin cabinet walls with no bracing. If you ever want these things to sound good, you need to take the drivers out of the cabinet, and build one with better bracing and damping. Crossover design could be perfect and they would still suck.

At which point the project spirals into a ship of theseus. If you are going to replace the cabinets, why not spend $15-30 per speaker on better tweeters?

The stock crossovers are so bad you will need to start from scratch. You need a mic that is at least mostly accurate, and an impedance sweeper. No way around spending that $80 unfortunately.



Then to do the measurements you need a reflection free area, and a measurement stand. Two key requirements, the speaker is far away from hard surfaces, and neither is the mic body, it should be on the end of a boom arm.


With good quality measurements, you can export the data into VituixCAD, design a crossover, and be ready to buy parts and solder.

If this sounds like a pain in the ass, it is. If you try to cut corners you will just end up with mediocre speakers, in which case you should just buy something like a pair of JBL Stage A130 and let the Yamaha NS-6490 be someone else's problem. Using pre-fab crossovers counts as cutting corners, utter waste of money.
 
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richardbruce

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Looking at the speaker measurement by amir, trying to fix these speakers is putting lipstick on a pig. Mineral wool is not going to fix the many resonances caused by the incredibly thin cabinet walls with no bracing. If you ever want these things to sound good, you need to take the drivers out of the cabinet, and build one with better bracing and damping. Crossover design could be perfect and they would still suck.

At which point the project spirals into a ship of theseus. If you are going to replace the cabinets, why not spend $15-30 per speaker on better tweeters?

The stock crossovers are so bad you will need to start from scratch. You need a mic that is at least mostly accurate, and an impedance sweeper. No way around spending that $80 unfortunately.



Then to do the measurements you need a reflection free area, and a measurement stand. Two key requirements, the speaker is far away from hard surfaces, and neither is the mic body, it should be on the end of a boom arm.


With good quality measurements, you can export the data into VituixCAD, design a crossover, and be ready to buy parts and solder.

If this sounds like a pain in the ass, it is. If you try to cut corners you will just end up with mediocre speakers, in which case you should just buy something like a pair of JBL Stage A130 and let the Yamaha NS-6490 be someone else's problem. Using pre-fab crossovers counts as cutting corners, utter waste of money.
Look - another totally negative comment! Ok, so I get it - these speakers couldn't be much worse. But they're what I have, and I'm convinced that if they can't sound any worse, they can be made to sound better. So please - while I appreciate your expertise, I don't appreciate people trying to discourage me. If you don't have a helpful comment, I prefer no comment at all - ok? Thanks!
 

alex-z

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Look - another totally negative comment! Ok, so I get it - these speakers couldn't be much worse. But they're what I have, and I'm convinced that if they can't sound any worse, they can be made to sound better. So please - while I appreciate your expertise, I don't appreciate people trying to discourage me. If you don't have a helpful comment, I prefer no comment at all - ok? Thanks!

If you choose to interpret a comment giving you detailed information on how to accomplish your goal as negative and unhelpful, not my problem.

I have been in your shoes before, trying to fix $100 speakers like Celestion 5 MKII and Micca MB42X. Putting in pre-fab crossovers and extra absorption material, only to come back years later with real measurement equipment and realize that after the mods they still didn't match up with $150 speakers.

I absolutely encourage DIY to learn more about audio, but fixing speakers in this fashion is precisely the same amount of work as designing a speaker from scratch. Like deciding you want to put a V8 engine in a FWD Honda Civic, there aren't many corners you can cut without disappointing yourself in the end.

If you decide to go the DIY route and get some measurements of the individual drivers, I would be happy to help you with the design work of the crossover.

If you decide to avoid that process, I recommend bracing the inside of the box with 1" wooden dowel, lightly stuffed it with polyfill, and using EQ to improve the response. EQ is always free, and in the case of the HS-6490 just pulling down 3dB above 600Hz with a high-shelf filter, and then 2 PEQ filters centred at 1000Hz and 3500Hz should yield a dramatic improvement.
 
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richardbruce

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If you choose to interpret a comment giving you detailed information on how to accomplish your goal as negative and unhelpful, not my problem.

I have been in your shoes before, trying to fix $100 speakers like Celestion 5 MKII and Micca MB42X. Putting in pre-fab crossovers and extra absorption material, only to come back years later with real measurement equipment and realize that after the mods they still didn't match up with $150 speakers.

I absolutely encourage DIY to learn more about audio, but fixing speakers in this fashion is precisely the same amount of work as designing a speaker from scratch. Like deciding you want to put a V8 engine in a FWD Honda Civic, there aren't many corners you can cut without disappointing yourself in the end.

If you decide to go the DIY route and get some measurements of the individual drivers, I would be happy to help you with the design work of the crossover.

If you decide to avoid that process, I recommend bracing the inside of the box with 1" wooden dowel, lightly stuffed it with polyfill, and using EQ to improve the response. EQ is always free, and in the case of the HS-6490 just pulling down 3dB above 600Hz with a high-shelf filter, and then 2 PEQ filters centred at 1000Hz and 3500Hz should yield a dramatic improvement.
So this is your idea of a positive comment to help me achieve my goal?

"trying to fix these speakers is putting lipstick on a pig"

Again, if they're as bad as Amir stated, then there's only one direction to go and that's up.

"Mineral wool is not going to fix the many resonances caused by the incredibly thin cabinet walls with no bracing"

I said that I was looking at/for mineral wool - not that I had decided on that. Acousti-fil seems to be the right solution for suspension speakers.

And surprise - when I opened the cabinet, there is bracing. Not much, but some. So there's that...

Turns out I found inexpensive mid-range speakers that match the crossovers I've got in mind perfectly.

So the total budget for this project is about $100. Where am I going to find 3-way speakers that can handle 100w for $150/pair? I live in an apartment, and don't have a wood shop filled with thousands of dollars worth of tools, let alone valuable tonewoods just laying around.

I'm quite happy with the suggestions I'm getting from No. 3 and I prefer to hear from him - or anyone else with helpful suggestions. Not highly technical one. Nor ones that recommend using an EQ that I don't have, and that I'm not going to buy. Not suggestions that are going to cost me a couple hundred dollars. And not ones that start out by trying to discourage me. This is the second time I've asked, and asked politely. But there is a limit to my patience with negative and overly technical audiophiles or audio snobs.

Thanks!
 
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richardbruce

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Alex-z, it appears as though your most recent comment was removed. Not sure if you deleted it, or an admin did. But your comments in general do not make a new member feel welcome nor comfortable. And in fact, I receive notification in my email of (and the content of) every comment when that comment is posted. Removing it from here does not keep it from my eyes. And in my eyes, your comments are both overly technical and unwelcome. I have a degree in electronics engineering - but I also live in an apartment. I don't have a woodshop nor the funds where I can buy and cut expensive tonewoods to the kind of exact tolerances required to make a great or even good speaker cabinet. That's not in my wheelhouse. My 1991 JVC has very limited "software" EQ. But matching crossover frequencies to speaker frequency curves is well within my wheelhouse. In addition, the physical size and sensitivity of this midrange not only fit the characteristics of the crossover and the Yamaha NS-6490 in general, but enhance it slightly. After 30+ years of experience in the electronics/electromechanical field, that is my ignorant, layman opinion.


Specifications
NS-6490
Type3-way acoustic suspension speaker system magnetic shielding type
Driver8" Cone Woofer, 4" Cone Mid-Range, 7/8" Balanced Dome Tweeter
Frequency Response45 Hz - 23 kHz
Nominal Impedance8 ohms
Nominal Input Power70W
Maximum Input Power140W
Sensitivity90 dB/2.83 V/m
General Crossover Frequency2.5 kHz, 8 kHz


Selected Crossover specifications:

Power: 180w
Impedance: 4Ω---8Ω
Frequency response: 850Hz/4800Hz
Treble filter characteristics: 12db/oct

Mid-range speaker specifications:
  • Paper cone and dustcap with cloth accordion surround
  • Natural vocal reproduction
  • Handles up to 80 watts RMS with 12 dB, 800 Hz high pass filter
  • Closed back design, requires no enclosure
    Impedance
    Frequency Response450 to 13,000Hz
    Sensitivity90dB 2.83V/1m




Another comment like the deleted one will be reported as inappropriate for a "senior" member of this group to make to a new member. Here it is for all to read:

How on earth do you think these crossovers match perfectly? You have no electrical or acoustic data on the drivers, you are shooting in the dark.

3 way speakers with 100 watt power handling, neither of those statistics has any relationship with speaker quality. For $150 a pair, the JBL Stage A120, or the C-Note DIY kit would both be good candidates.

https://www.crutchfield.com/p_109SA120AM/JBL-Stage-A120.html
https://www.parts-express.com/C-Note-MT-Bookshelf-Speaker-Kit-Pair-with-Knock-Down-Cabinets-300-7140
You absolutely don't need thousands of dollars in tools or materials to build speakers.

You don't need to use external EQ, just do it in software.

Go ahead, lose your patience if you think someone explaining the absolute basics of speaker design is an overly technical snob.
 
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alex-z

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Alex-z, it appears as though your most recent comment was removed. Not sure if you deleted it, or an admin did. But your comments in general do not make a new member feel welcome nor



Another comment like the deleted one will be reported as inappropriate for a "senior" member of this group to make to a new member. Here it is for all to read:
I deleted it because I realized I was wasting my effort trying to help you in any manner. Go ahead and report whatever you want, have a nice day.
 

ROOSKIE

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Alex-z, it appears as though your most recent comment was removed. Not sure if you deleted it, or an admin did. But your comments in general do not make a new member feel welcome nor comfortable. And in fact, I receive notification in my email of (and the content of) every comment when that comment is posted. Removing it from here does not keep it from my eyes. And in my eyes, your comments are both overly technical and unwelcome. I have a degree in electronics engineering - but I also live in an apartment. I don't have a woodshop nor the funds where I can buy and cut expensive tonewoods to the kind of exact tolerances required to make a great or even good speaker cabinet. That's not in my wheelhouse. My 1991 JVC has very limited "software" EQ. But matching crossover frequencies to speaker frequency curves is well within my wheelhouse. In addition, the physical size and sensitivity of this midrange not only fit the characteristics of the crossover and the Yamaha NS-6490 in general, but enhance it slightly. After 30+ years of experience in the electronics/electromechanical field, that is my ignorant, layman opinion.


Specifications
NS-6490
Type3-way acoustic suspension speaker system magnetic shielding type
Driver8" Cone Woofer, 4" Cone Mid-Range, 7/8" Balanced Dome Tweeter
Frequency Response45 Hz - 23 kHz
Nominal Impedance8 ohms
Nominal Input Power70W
Maximum Input Power140W
Sensitivity90 dB/2.83 V/m
General Crossover Frequency2.5 kHz, 8 kHz


Selected Crossover specifications:

Power: 180w
Impedance: 4Ω---8Ω
Frequency response: 850Hz/4800Hz
Treble filter characteristics: 12db/oct

Mid-range speaker specifications:
  • Paper cone and dustcap with cloth accordion surround
  • Natural vocal reproduction
  • Handles up to 80 watts RMS with 12 dB, 800 Hz high pass filter
  • Closed back design, requires no enclosure
    Impedance
    Frequency Response450 to 13,000Hz
    Sensitivity90dB 2.83V/1m




Another comment like the deleted one will be reported as inappropriate for a "senior" member of this group to make to a new member. Here it is for all to read:

How on earth do you think these crossovers match perfectly? You have no electrical or acoustic data on the drivers, you are shooting in the dark.

3 way speakers with 100 watt power handling, neither of those statistics has any relationship with speaker quality. For $150 a pair, the JBL Stage A120, or the C-Note DIY kit would both be good candidates.

https://www.crutchfield.com/p_109SA120AM/JBL-Stage-A120.html
https://www.parts-express.com/C-Note-MT-Bookshelf-Speaker-Kit-Pair-with-Knock-Down-Cabinets-300-7140
You absolutely don't need thousands of dollars in tools or materials to build speakers.

You don't need to use external EQ, just do it in software.

Go ahead, lose your patience if you think someone explaining the absolute basics of speaker design is an overly technical snob.
I think the advice you have been given by @alex-z is reasonable.
In large part because it quite accurate.

Nobody is dissuading you from DIY. Go for it and start learning. You are at the beginning and obviously have a lot to enjoy learning. Be cool being on your own, taking something apart that you may not be able to put back together - though you will learn and hopefully have some frustratingly fun times.

Beyond that it seems you feel entitle to avoid constructive criticism and have others hold your hand on what is likely a very uninteresting project for more experienced builders. This speaker is not a diamond in the rough that just need a little TLC. It is not a good speaker to mod for anyone with valuable time. Best not to kid yourself that your project offers something for very many others. You'd like folks to spend valuable hobby time and yet you don't want to spend $80 on an accurate microphone so it all seems a bit off. Which is fine - that is part of the learning curve, realizing this is a big investment of time and sometimes more money then seems to make sense unless you really want to be in the game.

The rockwool batting will not really help this speaker nor will any sort of $25 crossover.
All the people with experience know this just with a glance at the data and speaker and so will be unlikely to want to help you go down a valuable learners dead end. This is a 2+2=4 calculation.
Likely all of us have done this sort of thing back in the beginning, so I do understand why you maybe want to give it a go no matter what. You start where you start.

1. It needs oak Dowling or ply/MDF bracing in the cabinet, some 3 layer SonicBarrier on the cab walls

2. It need a complete crossover rework.
For a competent 3-way using low quality drivers (and thus more elements required to flatten and shape the poor driver responses) expect to spend $65-100 per speaker. Plus extra parts to switch things around a bit for the final tuning.

3. The drivers are high distortion and perhaps need to be re envisioned.
4. The dispersion is way off from "good" in terms of what most folks like. This can not be effectively changed unless drivers are changed and cabinets modified.

As was mentioned if you really want to tinker here, buy a PEQ and play around with DSPing the sound. It will be interesting say I. Plus that way the investment can be used on a better speaker in the next go around.

There are dedicated DIY audio sites that have a wide range of DIY interests and levels and maybe folks who might be more able and willing to help. If I was you I'd be hard pressed to anticipate DIYers who are on a site that uses a $100,000+ measurement system to be much into designing this speaker by ear or by Iphone mic (which while better than nothing is not nearly as accurate as a proper mic, it can work for bass corrections). Especially at the extreme beginner level of your approach.
IMhumbleHO any offense you are taking and your aggressive accusations are misguided.
 
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richardbruce

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I think the advice you have been given by @alex-z is reasonable.
In large part because it quite accurate.

Nobody is dissuading you from DIY. Go for it and start learning. You are at the beginning and obviously have a lot to enjoy learning. Be cool being on your own, taking something apart that you may not be able to put back together - though you will learn and hopefully have some frustratingly fun times.

Beyond that it seems you feel entitle to avoid constructive criticism and have others hold your hand on what is likely a very uninteresting project for more experienced builders. This speaker is not a diamond in the rough that just need a little TLC. It is not a good speaker to mod for anyone with valuable time. Best not to kid yourself that your project offers something for very many others. You'd like folks to spend valuable hobby time and yet you don't want to spend $80 on an accurate microphone so it all seems a bit off. Which is fine - that is part of the learning curve, realizing this is a big investment of time and sometimes more money then seems to make sense unless you really want to be in the game.

The rockwool batting will not really help this speaker nor will any sort of $25 crossover.
All the people with experience know this just with a glance at the data and speaker and so will be unlikely to want to help you go down a valuable learners dead end. This is a 2+2=4 calculation.
Likely all of us have done this sort of thing back in the beginning, so I do understand why you maybe want to give it a go no matter what. You start where you start.

1. It needs oak Dowling or ply/MDF bracing in the cabinet, some 3 layer SonicBarrier on the cab walls

2. It need a complete crossover rework.
For a competent 3-way using low quality drivers (and thus more elements required to flatten and shape the poor driver responses) expect to spend $65-100 per speaker. Plus extra parts to switch things around a bit for the final tuning.

3. The drivers are high distortion and perhaps need to be re envisioned.
4. The dispersion is way off from "good" in terms of what most folks like. This can not be effectively changed unless drivers are changed and cabinets modified.

As was mentioned if you really want to tinker here, buy a PEQ and play around with DSPing the sound. It will be interesting say I. Plus that way the investment can be used on a better speaker in the next go around.

There are dedicated DIY audio sites that have a wide range of DIY interests and levels and maybe folks who might be more able and willing to help. If I was you I'd be hard pressed to anticipate DIYers who are on a site that uses a $100,000+ measurement system to be much into designing this speaker by ear or by Iphone mic (which while better than nothing is not nearly as accurate as a proper mic, it can work for bass corrections). Especially at the extreme beginner level of your approach.
IMhumbleHO any offense you are taking and your aggressive accusations are misguided.
I never said that Alex-Z was incorrect - far be it for me to make that claim. I believe I've been quite clear in my replies. And my beef with him is one of attitude, not expertise.

I never said these speakers were a "diamond in the rough". In fact, I accept the technically detailed and substantiated evaluation presented in the other thread. Did you read that?

I never said I had decided on rockwool to line the cabinets. In fact, the general consensus within the speaker-building community is to line ported cabinets. This is an acoustic suspension-style speaker. I have since decided to stuff them with Acoustica-Fil.

I've also decided to replace the mid with a slightly better, yet reasonably-priced one that matches the selected crossover, since the woofer is doing most of the midrange work in Yamaha's cheap capacitor-only solution.

Why am I wasting my time on this project? Because I have more time than money, being retired after 30+ years in electronics/electromechanical repair, training, and support, as well as 10 years with the US Department of Defense. In my "beginner" opinion, it's worth $100 or so to try and improve these speakers, rather than just throw up my hands and say "there's nothing I can do" or buy another pair, and relegate these to storage space I don't have. AGAIN, if they're the worst speakers ever as y'all claim (they're not), then they can only get better, even if it's just a little.

So I will consider your comments, but I'll make my own decisions based on criteria other than purely technical. But why are you wasting YOUR valuable time and expertise commenting?
 
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