3 way definitive project — expert advice

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#23
Emanuele Del Piano said:
Forgive me, but unfortunately I am not technical enough to understand what you wrote. In this sense would you be willing to teach me by explaining it to me? Thanks.Anyway, my room is not dedicated to the system. It is a living room measuring 5x5 meters with a height of 3. The current speakers are at a distance of 2 meters and 20 more or less from each other, and about the same from the listening point. I do not have any acoustic treatment. However, I am looking for a speaker that returns more impact and dynamics especially from wind and string instruments. The current speakers are first series Platinum pl 200 audio monitors, purifi et400A pre topping pre 90 power amplifier, gustard X26III dac, and dedicated audio pc with all the attentions.
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So I’d assume you plan on some measuring equipment to build your speaker…..you can use that gear to measure your rooms reverb….or reverberant time. You can plug this in to the formula Fs = 2000 * sqrt(T60 / V) to get your room’s Schroeder.

Your room doesn’t need to be dedicated to the system….that’s the major benefit of DIY….now your system can be dedicated to the room!….taking advantage of the limits of acoustics, placement and size limitations.

I typically advise first time DiYers that sub Schroeder or most often low bass frequencies are the foundation to success. This is the modal region and the easiest to mess up and has little to do with the speakers or subs……80% of the response comes from the room. Mess this up and your low end will always sound congested or worse. Now the midbass is off balance or lacks any definition…..every kick drum rings on…..every cello sounds like a cardboard box……these modal frequencies can literally destroy the presentation of a $10k speaker.

If you’re serious about your title….lets start here and forget the predetermined notions you have.
 
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#24
Some good threads to study, for dsp-active 3-ways, by member hifijim

Projects:
hifijim

Thread 'New Project - tower 3-way with twin 8s'

I am in the planning stages of a new active 3-way project which I hope to build over the winter.

I have been curious about the Wondom JAB5 amp from Sure electronics. It is a 4 channel amp, 4 x 100W, with on board DSP via ADAU1701 DSP. SigmaStudio is used to program this little board. The cost for a JAB5 board, a programming board, a 36V power supply, and miscellaneous cables and connectors is about $160, compared to about $600 for a Hypex Fusion FA253. I am expecting the Hypex to be superior, due to the super-smooth nCore amps and the more sophisticated D/A & A/D processes on the...
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hifijim

Thread 'Compact, low cost, active 3-way speaker'

This is an idea which has been noodling about in my head for some time. A small portable active speaker, of modest cost. Something I can easily build multiple copies of, something I can give as a gift if I choose. I have friends who are decent woodworkers who have inquired about making a copy of one of my existing speakers, but they have balked at the expensive drivers and electronics I use… so this is something I can point to and say “you can copy this…”

I also like the idea of an expandable speaker where a second woofer cabinet can be added to extend the bass response and give higher...
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Tips:
hifijim

Thread 'VituixCad Simulations with Ideal Drivers'

This is an outgrowth of another thread. It was suggested that we needed a new thread where people could post their VituixCad simulations to enhance the general knowledge of cabinet diffraction issues and baffle layout.

It started with AllenB making a point:
Ironing a driver flat shouldn't be a problem if you choose the passband carefully, however there are many peaks and dips in measurements but many are not due to the drivers. If you EQ them all you may create problems.
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I added my thoughts:
To expand on what Allen is saying: It is very enlightening to experiment with...
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hifijim

Thread 'Driver Measurements Which Are Needed For Speaker Design'

This is an outgrowth of this other thread
https://www.diyaudio.com/community/...s-really-matter-for-sound.409770/post-7624912
… which turned into a wide ranging discussion about new forms of distortion, new ways of measuring and presenting distortion, and several other sub-topics. While that thread is informative and entertaining, it glosses over the practical application of measurements.

I would like to focus on those practical measurement techniques that are available today to a speaker designer. I want to discuss
(1) those measurements which should...
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hifijim

Thread 'Midrange Enclosure Internal Shape'

As I survey the many build threads over the last dozen years, I notice some people design complicated shapes for the midrange cavity: non-parallel walls, multifaceted shapes, tapered transmission lines, etc... while others use a simple box shape with good proportions.

I am searching for information on how midrange enclosure internal shape affects measured performance. There does not seem to be a lot of published literature out there, so I am interested in any measurements that anyone has done which show any effects.

Full disclosure: I am skeptical that a complicated internal shape...

Good basic info here too:
wintermute

Thread 'So you want to design your own speaker from scratch!'

You have been doing this DIY speaker thing for a while, probably built a couple of proven designs from people like Zaph , Troels Gravesen, Paul Carmody or any number of other successful designers.

Perhaps you started out like me, cobbling together random drivers with off the shelf or textbook crossovers, but never quite worked out why they didn’t work out as well as you imagined. You bought books like David Weems' “Designing Building and testing your own speaker system” and Vance Dickasons "Loudspeaker Design Cookbook" and have decided it is...
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https://sound-au.com/articles/index.htm#cros

Some 3-way projects:
http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm
https://pkaudio.webnode.cz/21w-12mu-9800/
 
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#25
Emanuele Del Piano said:
It is a living room measuring 5x5 meters with a height of 3. The current speakers are at a distance of 2 meters and 20 more or less from each other, and about the same from the listening point.
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Emanuele Del Piano said:
I am looking for a speaker that returns more impact and dynamics
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You're probably listening close to the middle of the room? The listening position in the center of the room can be a "null" point for certain low-frequency sounds, meaning there may be phase cancellations between the direct signal from the speakers and reflected sound waves. This can make the bass sound less impactful.
 
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#26
There are many room mode simulators, this is in RoomEQWizard.
I put the sub in the left corner, but the listener's head location is most critical. User can move speakers and mic/listener etc. parameters freely and see the response changing

Emanuele room sim rew.png
 
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#27
Hi there,

there are a couple of automatic room correction software / hardware solutions available that makes a good job

but before you come to this point even with an active crossover solution you need a decent measurement system and some knowledge to interpret the measurement graphs, which is the measurement system you want to use?

so far - so good, Stefano
 
#28
Emanuele Del Piano said:
I actually want to build something of my own that I will keep with satisfaction. But also to be able to play with. Monitor Audio are wonderful speakers, but the AMT tweeter and a 12 driver remain in the heart. I just bought a Xilica XP 4080. So now the fate is sealed 😅
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Go for it ! Horse poop on the fix the room redirect,
Everybody knows to do that, no matter what we are building. We're here to build speakers, no?
 
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#31
SBA_SLOB_GUY said:
Hi there,

there are a couple of automatic room correction software / hardware solutions available that makes a good job

but before you come to this point even with an active crossover solution you need a decent measurement system and some knowledge to interpret the measurement graphs, which is the measurement system you want to use?

so far - so good, Stefano
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At the moment I only have a usb microphone for my cell phone that costs a few euros. I wouldn't even know what to buy and why.
 
#32
Hi there,

i started years ago without a decent measurement system but as soon as i decided to go for a (not really cheap) Audiomatica Clio Pocket i realized that all the effort to find the settings only with my more or less good trained ears was more or less a guessing game

there are other options than Clio Pocket but it is easy to use and helps a lot

so far - so good, Stefano
 
#39
Emanuele Del Piano said:
What is an impedance jig? and how is it made?
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IMG_8796.jpeg

The LIMP manual (LIMP is part of the ARTA software bundle) shows it in its most simple and elegant way. It takes five resistors and a way to attach them to amp, soundcard input and Device Under Test. Alligator clips, banana plugs, cable and two 6,3mm jacks or two RCA plugs. No need for DATS or Clio.
 

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#40
Impedance sweep in free-air and in-box tell driver's resonances easier than spl response. Both are needed for full understanding and digging the ultimate best behaviour from speakers.

But I have made several pretty good dsp-actives without imps. Passive systems and bass-reflex require them or at least the data extracted from datasheet
 
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