I recorded the sound and publish to youtube
Rockport styled DIY 3-way speakers completed. Recording test. - YouTube
Rockport styled DIY 3-way speakers completed. Recording test. - YouTube
kimdh08:
Gorgeous work! Your video is helpful but inadequate: how do they sound to you?
Regards,
Scott
Gorgeous work! Your video is helpful but inadequate: how do they sound to you?
Regards,
Scott
Actually, it's hard to describe the subjective sound..
Scanspeak 6640 beryllium tweeter sounds so sweet and high resolution.
Audiotechnology 15h and 23i drivers have rapid response, deep tone color.
9-in double woofers play large scaled sound stage.
I generally satisfied with the sound..
I have recorded sound of the speakers.
DAC, preamp all self made.
Power amp is Emotiva XPA-2 gen2
Recording : RODE M5 stereo matched pair
DAC, preamp all self made.
Power amp is Emotiva XPA-2 gen2
Recording : RODE M5 stereo matched pair
Gorgeous looking enclosures, that is one of the nicer DIY enclosures posted on here that i have seen.
But that 6 inch baffle with no recess for the drivers, will and does give unwanted resonances.
There is a few in your impedance curves.
A little and informative writeup, with pics and graphs.
http://www.troelsgravesen.dk/chamfer.htm
Also elaborated on in Jim Moriyasu- STudy of midrange enclosures
But that 6 inch baffle with no recess for the drivers, will and does give unwanted resonances.
There is a few in your impedance curves.
A little and informative writeup, with pics and graphs.
http://www.troelsgravesen.dk/chamfer.htm
Also elaborated on in Jim Moriyasu- STudy of midrange enclosures
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@Arez
Thanks for pointing that out.
I didn't take a picture, but the chamfering is already applied.
However, the baffles are very thick, so they are shaped like the 'D' type on the Troels website you linked to, and the airflow behind the driver is good.
This is also the same shape on the Avior 2 from Rockport that I modeled.
Thanks for pointing that out.
I didn't take a picture, but the chamfering is already applied.
However, the baffles are very thick, so they are shaped like the 'D' type on the Troels website you linked to, and the airflow behind the driver is good.
This is also the same shape on the Avior 2 from Rockport that I modeled.
I measured the off-axis frequency response of the speaker. The speaker was too heavy to use a rotating disk, so I made a tool to easily move the microphone.
Below is a graph depicting off-axis response measurements, with reflections eliminated through gating (1.2ms).
I have only displayed frequency bands above 1k, primarily to assess the variation in directivity between the tweeter and midrange. Starting from the highest point, these angles are 0, 15, 30, 45, and 60 degrees, respectively.
The characterization remains consistent up to 7K, after which it becomes somewhat inconsistent between 7K and 9K. The minor dip observed at 0 and 15 degrees could potentially be substantially improved with the use of waveguides, although I have not conducted tests on this yet. Beyond 10k, the off-axis response generally performs well. While it may not exhibit the ideal shape, it remains acceptable considering factors such as room conditions, measurement errors, and so forth.
(Psychoacoustic smoothing, 1m distance, tweeter to midrange height, 50 dB/decade aspect ratio)
Below is a graph depicting off-axis response measurements, with reflections eliminated through gating (1.2ms).
I have only displayed frequency bands above 1k, primarily to assess the variation in directivity between the tweeter and midrange. Starting from the highest point, these angles are 0, 15, 30, 45, and 60 degrees, respectively.
The characterization remains consistent up to 7K, after which it becomes somewhat inconsistent between 7K and 9K. The minor dip observed at 0 and 15 degrees could potentially be substantially improved with the use of waveguides, although I have not conducted tests on this yet. Beyond 10k, the off-axis response generally performs well. While it may not exhibit the ideal shape, it remains acceptable considering factors such as room conditions, measurement errors, and so forth.
(Psychoacoustic smoothing, 1m distance, tweeter to midrange height, 50 dB/decade aspect ratio)
I recently purchased a waveguide from Aliexpress, attached it temporarily, and measured its directivity.
I measured from 0 to 150 degrees, and the graph below is the response without normalization.
Here is the graph with normalization applied.
Here is
Above 8 kHz and beyond 120 degrees, you can see some unevenness in the directional characteristics, but that's pretty good.
The following is a polar map.
I gated the time window to 5ms, so below 500Hz is not significant. The tweeter/mid COP of this speaker is around 2.8 kHz, and the mismatch in directivity at that point is not significant due to the waveguide and offset baffle geometry.
I measured from 0 to 150 degrees, and the graph below is the response without normalization.
Here is the graph with normalization applied.
Above 8 kHz and beyond 120 degrees, you can see some unevenness in the directional characteristics, but that's pretty good.
The following is a polar map.
I gated the time window to 5ms, so below 500Hz is not significant. The tweeter/mid COP of this speaker is around 2.8 kHz, and the mismatch in directivity at that point is not significant due to the waveguide and offset baffle geometry.
Hi ! sincere congratulation for your impressive creations I admire Rockport speakers too after reading this old review
https://www.stereophile.com/floorloudspeakers/644/index.html
i listened to them just one time at an audio show Amazing sound
i would like to ask how did you decide for using MDF sheets only and a total thickness of 5 in. Did you follow any guidelines ?
i am studying baffles design and construction In some cases i have seen sheets of different woods sandwiched .. like one sheet of mdf/hdf and one sheet of plywood alternate glued and pressed together The reason from what i have understood is to provide both damping and stiffness
In my dream i would try metal and mdf But i am afraid it will remain just a dream I lack skills and tools
Sincere congratulations again
@ginetto61
Thank you for your interest.
The 5-inch thickness was inspired by the baffle design of Rockport's Avior2 speakers. Similarly, speakers like Avalon also use multiple layers of MDF to achieve baffles of comparable thickness.
While I didn’t use a combination of MDF and HDF, I incorporated epoxy resin instead of MDF for certain parts, such as the beveled edges of the baffle. Using different materials helps to distribute resonances across a range of frequencies rather than concentrating them at specific points.
Rockport’s higher-end models use various composite materials, including aluminum baffles, but models up to the Avior2 were constructed using MDF. I’m also very interested in aluminum baffles, but machining them into the desired shapes is practically impossible for DIY projects due to the high costs involved.
Thank you for your interest.
The 5-inch thickness was inspired by the baffle design of Rockport's Avior2 speakers. Similarly, speakers like Avalon also use multiple layers of MDF to achieve baffles of comparable thickness.
While I didn’t use a combination of MDF and HDF, I incorporated epoxy resin instead of MDF for certain parts, such as the beveled edges of the baffle. Using different materials helps to distribute resonances across a range of frequencies rather than concentrating them at specific points.
Rockport’s higher-end models use various composite materials, including aluminum baffles, but models up to the Avior2 were constructed using MDF. I’m also very interested in aluminum baffles, but machining them into the desired shapes is practically impossible for DIY projects due to the high costs involved.
I often think of this project. It’s one of the most thorough and best looking DIY speaker system I’ve ever seen.
If you wish to try machined aluminum parts, I can recommend LAVA 3D Printing in China, also know as precintl. I have hired them multiple times for laser cut steel and cnc aluminum in various grades., and the costs are reasonable. The appearance is exactly as you design it.
Personally, I feel MDF of HDF is good enough. I’m impressed you mentioned HDF, most people I take to are unfamiliar with it. It machines like plastic and will hold a razer sharp edge.
If you wish to try machined aluminum parts, I can recommend LAVA 3D Printing in China, also know as precintl. I have hired them multiple times for laser cut steel and cnc aluminum in various grades., and the costs are reasonable. The appearance is exactly as you design it.
Personally, I feel MDF of HDF is good enough. I’m impressed you mentioned HDF, most people I take to are unfamiliar with it. It machines like plastic and will hold a razer sharp edge.
Hi good morning 🙂
lately i switched my attention to speakers design and construction Also after knowing of this blind test
https://www.matrixhifi.com/ENG_ppec.htm
i am now more conscious of the impact of loudspeakers on the sound of a system
I got very kind and valuable advice that made me aware of how big is the influence of the cabinet on the sound of a speaker
and moreover how important is the design and construction of the front baffle
Then i found your excellent project where the baffle is really amazingly built I'm sure your speakers would make a great impression at a high end audio show too.
thank you very much for your great advice I have to sum up what i learned from other threads
The stiffness acts moving the cabinet resonances up in frequency The mass instead moves the resonances down in frequency
If the speaker would be of the two pieces kind i.e. with a mid-hig head above a bass body the ideal cabinets would be a very stiff one for the woofers and a very heavy one for the head
unfortunately i would say speakers come monolythic with all different drivers in a same cabinet
Imho this complicates the design because the cabinet needs a combination of stiffness and mass I guess that to have both high is very good
The best sounding speakers have usually high mass and stiffness
To be more precise my reference speakers could be something of the like of the rockport merak/sheritan
or avalon monitor above a bass box or the wilson audio watt plus puppy Mainly because i prefer to keep separated mechanically the bass box from the mid high section They would be also easier to move around i guess
if stiffness is important nothing beats metals Usually the resonances of metal cabinets are higher in frequency and low in energy
some damping sheets strategically placed in the center of panel can neutralize these resonances
the metal would be a gods gift for the bass box Krell has used metal for a sub cabinet
i see the design and construction of cabinets for subwoofers as one of the most challenging tasks in speakers design and construction
very very difficult to get right
Another wierd ideas would be to design and build a cabinet good for a sub and place a coaxial in it
i have studied a little Tannoy speakers I am more than sure that the performance of their drivers is held back by the not optimal cabinets
at least for more common models
but a very good coaxial costs a lot indeed
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