Tip for DSP education:
A Beginner's Guide to Digital Signal Processing (DSP) | Analog Devices
And the two referenced in the above
Analog Devices: Analog Dialogue: Digital Signal Processing 101* An introductory course in DSP system design: Part 1
The Scientist & Engineer's Guide to Digital Signal Processing | Analog Devices
If one understand this, the possibillities are endless.
As of cabinets I have good results with one volume for each speaker element. Then they are easy to model and do not interfere inside the cabinet. High Q (under 1.41) is no problem in my experience when the element is cut at more then 2 times fs box and sharp filters.
The scan speak xls box simulation is great:
Scan-Speak
As long as sharp filters is used volumes with sides more then 1 wavelength needs no damping. (But is does not hurt either)
At 1/2 wavelength use thick damping to avoid standing waves! Often this only apply to one of the volumes in a 4 way system as the tweeter in most cases has its own internal chamber.
Last edited:
That should be wavelengths longer than double longest wall length!
That means frequencies lower than c/(double wavelength)
Just an example of standing waves and cancellations:
34 cm internal length of longest wall:
Frequency 1 wavelength: 1000Hz. Standing wave.
Frequency double wavelength: 500Hz. If reflexion from walls at 500Hz, 500Hz will be cancellated because of reflexion 180degrees out of phase.
17 cm internal length doubles the frequencies but 1000Hz waves are relative easy to dampen with acqustic sound absorbing materials.
So walls less then 34 cm frequensies under 500 Hz don't need to be dampened or absorbed.
Walls less then 17 cm with frequencies including 1000 Hz and 500 needs to be dampened with acqustic sound absorbing materials working at 500Hz and above.
Less than 8 cm and the low damping frequency is 1000Hz.
So with sharp filters 48db/oct and up:
20-70Hz 100 cm longest wall length. No internal waves, just preasure. (Tube or sphere best internal walls.)
70-400Hz. 34cm longest wall. No internal waves, just preasure.(Tube or sphere best internal walls.)
400-2500Hz. 17 cm longest wall. Internal standing waves from 500Hz and up. Needs to be dampened with acqustic sound absorbing materials working from 500Hz and up. (and/or wall construction)
2500Hz-up. Tweeter has often internal closed chamber. No external damping or wallshapes needed.
I think this ease the cabinet construction a great deal. The woodwork still is hard to do
Just my own personal philosophy
That means frequencies lower than c/(double wavelength)
Just an example of standing waves and cancellations:
34 cm internal length of longest wall:
Frequency 1 wavelength: 1000Hz. Standing wave.
Frequency double wavelength: 500Hz. If reflexion from walls at 500Hz, 500Hz will be cancellated because of reflexion 180degrees out of phase.
17 cm internal length doubles the frequencies but 1000Hz waves are relative easy to dampen with acqustic sound absorbing materials.
So walls less then 34 cm frequensies under 500 Hz don't need to be dampened or absorbed.
Walls less then 17 cm with frequencies including 1000 Hz and 500 needs to be dampened with acqustic sound absorbing materials working at 500Hz and above.
Less than 8 cm and the low damping frequency is 1000Hz.
So with sharp filters 48db/oct and up:
20-70Hz 100 cm longest wall length. No internal waves, just preasure. (Tube or sphere best internal walls.)
70-400Hz. 34cm longest wall. No internal waves, just preasure.(Tube or sphere best internal walls.)
400-2500Hz. 17 cm longest wall. Internal standing waves from 500Hz and up. Needs to be dampened with acqustic sound absorbing materials working from 500Hz and up. (and/or wall construction)
2500Hz-up. Tweeter has often internal closed chamber. No external damping or wallshapes needed.
I think this ease the cabinet construction a great deal. The woodwork still is hard to do
Just my own personal philosophy
Last edited:
Thanks for the links, I have had for a while The Scientist and Engineer's Guide to Digital Signal Processing's Table of Content
great resource, just glancing at the same from Analog Devices looks to be interesting as they tie the book to their product. I'm a bit of an old guy so my taste tend a little more to the vintage side of life. It is a fun hobby.
Attachments
![20150901_125325[1].jpg](/community/data/attachments/463/463041-ce76e0491c1a3864f9f7f6699ec1668b.jpg)
See why you need a low noise crossover
My 4 way suggestion is meant for non horn....
I have been suprised how loud and clean conventional elements can play when used with sharp filters enough volume displacement and small bandwith eg 4 way.
But, the beauty of a nice horn is somthing to else.
My 4 way suggestion is meant for non horn....
I have been suprised how loud and clean conventional elements can play when used with sharp filters enough volume displacement and small bandwith eg 4 way.
But, the beauty of a nice horn is somthing to else.
Have you seen any positive updates from ESS regarding the ADCs yet? I wind it rather worrying that they have removed all their ADCs from their website, and so has their distributor. Maybe the 5397 from AKM is an option? Premium ADCs | Product | AKM - Asahi Kasei Microdevices
I believe they have an alternative to the 9018 as well through their 4490. I doubt it is as far behind as the numbers would suggest, and there would indeed be a lot of money to be saved. I believe it to be significantly better performing than the 1795 from TI as well.
I believe they have an alternative to the 9018 as well through their 4490. I doubt it is as far behind as the numbers would suggest, and there would indeed be a lot of money to be saved. I believe it to be significantly better performing than the 1795 from TI as well.
I believe they have a new drop-in replacement part for the ES9102C called the ES9108PRO but it won't be available for sometime. I can still use the ES9102C without some of the features which would save me from re-designing the pcb layout for another part such as the AK5397.
Also has anyone had any luck buying parts from esstech outside the US ? For some reason they don't have the ability to send outside the US and so you need to use your own freight forwarder etc. No idea how to do this and how much it would cost just to get a couple of parts for evaluation.
I am used to ordering from ebay, element14, digikey mouser etc. No problems with that. In fact believe it or not I got the ES9018S from ebay although I am amazed it still worked being sellotaped on to a bit of polystyrene foam
cheers
I'm also in Oz, and I have regularly used Price USA | Shop where you want , and based upon my experience can recommend them highly. They are a couple of Aussies, on here and one in Colorado. You tell them what parts to order, or order them yourself if you need to log in securely yourself, and have them shipped to Colorado. They then confirm the order is correct and can ship them via a couple of carriers to Aus. They add 5% (or it was last time I did it) of the value, though if you pay for it yourself, it will likely just be on shipping. Very good communications and nice to deal with.
There are others who may be just as good, but I've bought several $k of gear through them, all with zero problems.
Haha, I hope you do not plan to source this through e-bay?
I put a 9006 into a design that is currently being manufactured in Nanjing, China. They had a similar problem (the ESS representative in China wanted a huge mark up on the ESS chips), so we sourced it for the factory, through the local Ismosys representatives. If you want, I can off course send a few e-mails to help you get a usable connection.
I put a 9006 into a design that is currently being manufactured in Nanjing, China. They had a similar problem (the ESS representative in China wanted a huge mark up on the ESS chips), so we sourced it for the factory, through the local Ismosys representatives. If you want, I can off course send a few e-mails to help you get a usable connection.
Yes please do
And no I don't plan to source it through ebay although it was easier to get it from ebay than it was through the so called distributors !!
cheers
It is sad that so many distributors around the world are in the "so called"-category. Like distribution is a very hard thing to do when customers actively contacts you and asks if they can please purchase your products...
I have sent an e-mail, but it is really early here in the cold north, so I do not expect any answer in a while. However, I will need some contact info to you. Let's take that on PM.
I have sent an e-mail, but it is really early here in the cold north, so I do not expect any answer in a while. However, I will need some contact info to you. Let's take that on PM.
Several people have asked me how I intend to handle USB or computer audio. Just to get the ball rolling I spent some time connecting up the Amanero Combo USB interface board because I have not yet built the proper interface adaptor for it which includes the isolators. It's working with Jriver no problems !!
cheers
An externally hosted image should be here but it was not working when we last tested it.
There's an I2S input interface on the Digital Audio Interface board which conforms to the PS-Audio standard. There is also an additional I2S output on the board.
cheers