my first 3way Peerless loudspeaker....

[mpbraj]

Dear Team, This is going to be my first three way tower..I have been going through this forum I should appreciate the help provided to the fellow first timers...Ok, on to my project, below is my list of drivers...

Peerless woofer - sn20nl (8" driver )
Peerless Mid - sko130 (5.25")
Peerless tweeter - TL26SG

extracted woofer spec with LIMP(Arta) is as below

Fs - 43.21 hz
Re - 5.80ohms(DC)
Le - 525.27 uH
L2 - 1594.27uH
R2 - 31.89Ohms
Qt - 0.44
Qes = 0.48
Qms - 5.09
Mms - 37.96 gms
Rms - 2.023 kg/s
Cms - 0.000357 m/N
vas - 22.94 ltr
sd - 213.82 cm^2

I was able to simulate the woofer with Unibox, dual woofer is parallel, after going through this forum and some other forums, I am attaching the screeenshot and the graphs, Can somebody please advice if I am doing it right..


Thanks and regards,
Babu...

 

[kapvin]

Dear Team, This is going to be my first three way tower..I have been going through this forum I should appreciate the help provided to the fellow first timers...Ok, on to my project, below is my list of drivers...

Peerless woofer - sn20nl (8" driver )
Peerless Mid - sko130 (5.25")
Peerless tweeter - TL26SG

extracted woofer spec with LIMP(Arta) is as below

Fs - 43.21 hz
Re - 5.80ohms(DC)
Le - 525.27 uH
L2 - 1594.27uH
R2 - 31.89Ohms
Qt - 0.44
Qes = 0.48
Qms - 5.09
Mms - 37.96 gms
Rms - 2.023 kg/s
Cms - 0.000357 m/N
vas - 22.94 ltr
sd - 213.82 cm^2

I was able to simulate the woofer with Unibox, dual woofer is parallel, after going through this forum and some other forums, I am attaching the screeenshot and the graphs, Can somebody please advice if I am doing it right..


Thanks and regards,
Babu...

it needs to be tuned a bit lower. It's underdamped; so you bass will boom just a bit.

ps - have you run them in? specs can chnage post run in.

 

[mpbraj]

HI Kapvin, Many many thanks for the reply..made some change, reduced FB to 35Hz with Heavy fill, two flared end ports, also the Impedance graph from the previous post not very satisfying...Let me know.

Babu

 

[mpbraj]

Dear all, Anybody out there to provide some help....

Babu

 

[mpbraj]

Dear all, here is another one attached....let me know...

 

[hydrovac]

Before embarking on this task, it is important to decide what you are looking for out of this project. However having an idea what to expect out of the finished product is important, so you have goals to work towards.

* Cost
* Size
* Power Output
* Frequency response
* Weight
* Appearance

I do not know your your experience with speaker building though, very risky...3 ways are tough. You'd be way better off with a kit, all the engineering has been done, you'll save a lot of time/money and end up with a better project.

From the begging of the project, you are planning a 4 driver 3 way design. A crossover network would also be designed and implemented to compliment the characteristics of the speakers. At this juncture, it is important to note that the T/S parameters from the loudspeaker manufacturers do not always match the actual parameters.

If precision is key it is important to determine the actual T/S parameters of a loudspeaker before moving forward with the design. It is often useful to model response using the manufacturers data sheet for a ballpark before purchasing a driver and then measure the actual T/S parameters before proceeding with the design.

I hope this advice helps out budding speaker builders and allows first the first project to be successful. Start out with a smaller project first, and build up to more challenging projects as your knowledge and skill increase.

Cheers

 

[tcpip]

it needs to be tuned a bit lower. It's underdamped; so you bass will boom just a bit.

Is this underdamped? Shit!:sad: I always confuse underdamped and overdamped. I am under the impression that if you put the speaker in a box and you get a Q higher than 0.7, then it's overdamped (as is the case here), and if you get a Q lower (as is the case with my speakers), then it is underdamped.

I agree with your suggestion, of course -- this speaker will boom a bit unless the enclosure is enlarged.

 

[kapvin]

Is this underdamped? Shit!:sad: I always confuse underdamped and overdamped. I am under the impression that if you put the speaker in a box and you get a Q higher than 0.7, then it's overdamped (as is the case here), and if you get a Q lower (as is the case with my speakers), then it is underdamped.

I agree with your suggestion, of course -- this speaker will boom a bit unless the enclosure is enlarged.

Yes, it sounds just a bit counter intuitive to me as well but a simple rule of thumb I use to remember which is which is "control over the cone." Hi q = low control, underdamped. Low q=high control = over damped. Ringing = underdamped, tapering bass= over damped

Best wishes

 

[tcpip]

mpbraj, I have not used Arta, so I don't know what it can do. Can it take MLS measurements? Do you have a measurement mic, etc?

Unless you have the setup (and time/ willingness) to do SPL and impedance measurements, please do not execute this project.

I may sound harsh, but I don't know any other ways to say it: I feel it is crazy to try to build a large, expensive speaker system using stock crossovers. You must measure the drivers in their enclosure, get SPL and phase measurements, and then design the crossovers yourself. The software to do this is free (Speaker Workshop), but you need (i) a measurement mic, (ii) an impedance jig, and the time/ willingness to learn how to do measurements and crossover modelling.

I see Indian DIY projects being published on various forums, blogs, even on the diyaudiocart.com site, where people build massive floorstanders with 3-way 3-driver and 3-way-4-driver configurations, and take a lot of trouble finishing the exterior, trying to get a lovely appearance, and so on. But they

• don't brace their massive cabinets even one-fourth as much as is needed, thereby guaranteeing an enclosure which sings like a drum, giving muddy soundstage and muffled sound
• don't do any speaker measurements, using a stock crossover instead

This seems to me to be such a waste of the builder's time, money and energy that I simply cannot understand why they do it. It's absolutely heart-breaking. "Horses for courses", my friends tell me. They tell me that if the builder is happy, why should I comment? But if you are a horse-lover and have to watch a superb animal being misused in horrible courses, your heart is bound to break.

Please tell me you intend to do SPL, impedance and phase measurements of your drivers, you have a measurement mic and impedance measurement jig, and intend to design your crossovers using xo modelling software.

 

[tcpip]

I will elaborate on the details of speaker designing as I see it, having two and a half projects under my belt now.

• Driver choice is 10% of the job. You need to have reasons why you chose the three drivers you did. How do they fit into the overall goal of your speakers? For an example of such goal setting, see this page which discusses another 3-way design
• Enclosure design, and construction details, contribute 40% to the speaker's performance. By "enclosure design", I do not refer to box modelling -- that part is 5%, whereas construction details are 35%. By construction details, I mean only one thing: how will you build an enclosure which does not radiate any sound from the panels and front baffle, and which does not add distortion due to reflections of the driver's rear wave? I kid thee not, I really believe that a full one-third of the performance of a finished speaker depends on just construction details of the enclosure. A speaker enclosure is not a simple rectangular box.
• Crossover design accounts for 50% of the performance of the speaker. To do crossover design, you need to take SPL and impedance measurements of the drivers in the enclosure, you need the hardware and software setup to do MLS measurements, and then you need to design the crossover using xo modelling software (which is available free for passive crossovers -- Speaker Workshop). You need to know what is nearfield measurements (needed for 3-way and above) and you need to know what is gated farfield or MLS measurements.

Unless you are prepared for this, build a kit. It will give you excellent performance, because someone else has done the designing for you. And pour your heart into meticulous construction and finishing of the exterior -- you will be proud of it. Today, a full kit of 2-way speakers and 2-way MTM speakers is available from bajaao.com -- these kits use imported Dayton Audio drivers and will probably be a hundred times more accurate than anything built using stock crossovers.

Try as I might, I cannot understand how DIY builders in India, living in this Internet era, browsing all these info-filled forums, knowing all about these requirements (which I have listed above) still pour their money into building speakers with unknown drivers and stock crossovers.

I really wish I knew how to make my message softer, more polite, but I don't. As you can guess, I have very few friends.

 

[tcpip]

Yes, it sounds just a bit counter intuitive to me as well but a simple rule of thumb I use to remember which is which is "control over the cone." Hi q = low control, underdamped. Low q=high control = over damped. Ringing = underdamped, tapering bass= over damped

Should have checked earlier. :signthankspin:

Will have to go and edit my webpages. Most embarassing. Better late than never, I guess.

Good page here which explained the basics to me.

 

[kapvin]

Should have checked earlier. :signthankspin:

Will have to go and edit my webpages. Most embarassing. Better late than never, I guess.

Good page here which explained the basics to me.

Just a small mistake, the way I wrote, it looks like cause and effect got mixed up.. overdamped =low q; not the other way around.(i.e not low q=overdamped)

 

[kapvin]

I will elaborate on the details of speaker designing as I see it, having two and a half projects under my belt now.

• Driver choice is 10% of the job. You need to have reasons why you chose the three drivers you did. How do they fit into the overall goal of your speakers? For an example of such goal setting, see this page which discusses another 3-way design
• Enclosure design, and construction details, contribute 40% to the speaker's performance. By "enclosure design", I do not refer to box modelling -- that part is 5%, whereas construction details are 35%. By construction details, I mean only one thing: how will you build an enclosure which does not radiate any sound from the panels and front baffle, and which does not add distortion due to reflections of the driver's rear wave? I kid thee not, I really believe that a full one-third of the performance of a finished speaker depends on just construction details of the enclosure. A speaker enclosure is not a simple rectangular box.
• Crossover design accounts for 50% of the performance of the speaker. To do crossover design, you need to take SPL and impedance measurements of the drivers in the enclosure, you need the hardware and software setup to do MLS measurements, and then you need to design the crossover using xo modelling software (which is available free for passive crossovers -- Speaker Workshop). You need to know what is nearfield measurements (needed for 3-way and above) and you need to know what is gated farfield or MLS measurements.

Unless you are prepared for this, build a kit. It will give you excellent performance, because someone else has done the designing for you. And pour your heart into meticulous construction and finishing of the exterior -- you will be proud of it. Today, a full kit of 2-way speakers and 2-way MTM speakers is available from bajaao.com -- these kits use imported Dayton Audio drivers and will probably be a hundred times more accurate than anything built using stock crossovers.

Try as I might, I cannot understand how DIY builders in India, living in this Internet era, browsing all these info-filled forums, knowing all about these requirements (which I have listed above) still pour their money into building speakers with unknown drivers and stock crossovers.

I really wish I knew how to make my message softer, more polite, but I don't. As you can guess, I have very few friends.

this is a mail that i was going to write, but never got around to, so thank you.

my views are a bit less extreme, and I believe that as long as one fully understands that DIY is a multi stop journey rather than a single point, "build and be happy", it's okay to "start wrong".

everything you say is right; though one could argue about the bias between items for eg - good driver choice obviate the need to bend your mind on the crossover; but as long as one is willing to tweak the speaker (an essential item in DIY) i think starting simple is fine.

however, measurement is the key to building a good speaker, and a good mic is essential as is some method of measuring small signal parameters of speakers (T?s parameters - i am not familiar with ARTA but I think limp allows you to measure using a computer sound card and a simple circuit)

more later.. need to get to the business of daily bread earning.

 

[tcpip]

everything you say is right; though one could argue about the bias between items for eg - good driver choice obviate the need to bend your mind on the crossover; but as long as one is willing to tweak the speaker (an essential item in DIY) i think starting simple is fine.

:lol: I agree. The calculations I have given are more my perspective than any universal formula. However, I have begun to feel that even with pretty "easy" drivers, the difference between mediocre and excellent is a lot of work on the crossovers. i have walked into a room where a friend is demo'ing his DIY speakers, and the brightness of the highs, or the bloated lower mids, hits me. I don't have the heart to tell him that he needs a month more of trial and tweaking of his crossover. This sort of experience is quite common -- a lot of DIY speakers are actually nowhere near the full potential which their drivers and enclosure can take them, because we feel that a software-optimised straight-line crossover designed in fifteen minutes is the best that one needs to do.

I read about Lynn Olson's Ariel, and was amazed at the effort he put into building its crossover. And he had chosen particularly easy drivers -- the mid-bass units were Vifa poly-cone units with no cone breakup or other unpleasantness anywhere in sight. I feel that as a DIYer, if I put in money to build something but don't do the "DIY" bit of tweaking and tuning to get the best out of it, it's a missed opportunity, isn't it? And if I do start tweaking, then the crossover easily accounts for 50% or more of my time.

Thanks for understanding what I was trying to say. And I am really glad that no one seems to have taken my comments as a personal criticism of any project.

 

[mpbraj]

Dear All, I am building this 3way for one of my friend for which he has already paid some advance towards it....I am keen on completing this project with some help on this community. I have built loudspeakers but with out any simulation with Dainty drivers..But now I want to build it with perfect configuration for which simulation is required..

The drivers are procured from diyaudiocart.com, they are peerless drivers.

I have just played with unibox, attached are the two results of it. one with hockey bat is what I prefer but the box volume is too large, the other one actually I want lower the lower bass since this will be centre speakers so I can use subwoofers...

Thanks for the replies...Let me know, I need some help to go further..

Regards..

 

[kapvin]

Dear All, I am building this 3way for one of my friend for which he has already paid some advance towards it....I am keen on completing this project with some help on this community. I have built loudspeakers but with out any simulation with Dainty drivers..But now I want to build it with perfect configuration for which simulation is required..

The drivers are procured from diyaudiocart.com, they are peerless drivers.

I have just played with unibox, attached are the two results of it. one with hockey bat is what I prefer but the box volume is too large, the other one actually I want lower the lower bass since this will be centre speakers so I can use subwoofers...

Thanks for the replies...Let me know, I need some help to go further..

Regards..

using your specs and unibox i get a Vb of 60litres with an fb of 39hz and 11cm dia port with a length of 16.6cm. looks perfectly workable.

woofers wired in paralell (since they are 8ohm nominal)

what are you doing differently?

 

[mpbraj]

Kapvin,

I have tried that but the Port air speed is touching the Red line, I hope it has to be below the brown line..

Regards,

 

[kapvin]

My graph is looking very different from your graph. 60litres is close to maximally flat. I think you are doing something differently

 

[tcpip]

I have tried that but the Port air speed is touching the Red line, I hope it has to be below the brown line..

Relative to other challenges you are facing and will face, I suggest that the port air speed worries are minor. Ignore it. See why your sim is not matching Kapvin's -- that is a bigger issue.

 

[kanwar]

mpbraj I may sound harsh, but I don't know any other ways to say it: I feel it is crazy to try to build a large, expensive speaker system using stock crossovers. You must measure the drivers in their enclosure, get SPL and phase measurements, and then design the crossovers yourself. The software to do this is free (Speaker Workshop), but you need (i) a measurement mic, (ii) an impedance jig, and the time/ willingness to learn how to do measurements and crossover modelling.I see Indian DIY projects being published on various forums, blogs, even on the diyaudiocart.com site, where people build massive floorstanders with 3-way 3-driver and 3-way-4-driver configurations, and take a lot of trouble finishing the exterior, trying to get a lovely appearance, and so on. But they

• don't brace their massive cabinets even one-fourth as much as is needed, thereby guaranteeing an enclosure which sings like a drum, giving muddy soundstage and muffled sound
• don't do any speaker measurements, using a stock crossover instead

This seems to me to be such a waste of the builder's time, money and energy that I simply cannot understand why they do it. It's absolutely heart-breaking. "Horses for courses", my friends tell me. They tell me that if the builder is happy, why should I comment? But if you are a horse-lover and have to watch a superb animal being misused in horrible courses, your heart is bound to break.

Please tell me you intend to do SPL, impedance and phase measurements of your drivers, you have a measurement mic and impedance measurement jig, and intend to design your crossovers using xo modelling software.

Try as I might, I cannot understand how DIY builders in India, living in this Internet era, browsing all these info-filled forums, knowing all about these requirements (which I have listed above) still pour their money into building speakers with unknown drivers and stock crossovers.I really wish I knew how to make my message softer, more polite, but I don't. As you can guess, I have very few friends.

Tarun,

People, especially the majority of Indian DIY-community doesn't go my measurements, what they go by is 'Looks to please, Warm color of Veneer to match their furniture, Use of famous drivers to get the audiophilic feel and Judging the sonics through their GOLDEN EARS' .............. Now who needs the scientific data when the 'colorful' sound is at top of the wish list... hyeah:


Kanwar