Designing Full Range Speakers and Stands

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There is no doubt that I should improve my stereo system. The next step, however, has to involve the proper placement of speakers in the room. At present I have the Diamond IV next to my desk, on either side, great for near-field. If I am ever to get out the near-field, though, I need the speakers to be placed in the room. about one third of the way into the room. Many other arrangements have been tried: open baffle speakers, on wall open baffle speakers, and even attempting at home to move the floorstanders to the floor where they belong (Sony SS-333). That did not work out well.

Initial tests with this arrangement have been encouraging. Paul McGowan of PS Audio ("Ask Paul") talks about attempting to design speakers that can be placed "2 -3 feet' from the walls, this seems to be the minimum. One third into the room, and if I sit one third of the way into the room, things get quite good as far as listening goes. The equilateral triangle means then that the speakers have to be placed apart. In all my years of listening I did not experience the stereo effect (outside of headphones) until 2019 or so, at my desktop.

We had a rack "home H-Fi" system (1980s) but the speakers were placed on either side of the rack, like large blocks, the stereo effect was unheard of, we just wanted to play it loud and fill the room with sound. That we did.

Since any room will look strange with a set of boxes on stands in the middle of the room, these will have to be pushed back after use each time, and be able to be stored unobtrusively. There is a potential problem here. Wikipedia, with rare literary flair, puts it this way:

The JBL TI 5000 loudspeaker boxes are 1.15 m tall and, like all large HiFi boxes, ideally should be placed distinct from room corners. Such devices are an example for a rather low WAF.

This thread will then describe results.

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Those Diamond IVs are nice speakers, however, my design was not placement only, design of full range + stands. I am much more careful with the full range categorization now. I should have been more specific about the speaker design itself...

There is a thread I should have read: https://www.diyaudio.com/community/threads/designing-principles-for-near-the-wall-speakers.199712/

Here is a prototype built earlier. Cardboard prototype.

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https://www.diyaudio.com/community/threads/are-cardboard-enclosures-any-good.394837/page-6
 

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I did some listening with the speakers against the wall, and a little away from the wall. The best position is about 30% into the room.
The music sounds like it is coming from the middle of the room: I have never heard a group play with their back against the wall, nor a singer
resting against the far wall. It stands to reason, then, that music will sound more natural when it emanates from somewhere in the room. I do not see myself going back to near-wall speakers for listening.

Listening was done by using a single speaker.

The design for the stands is now complete, just a prototype needs to be constructed. Now on to the design of the speakers.

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Is there a reason you are looking at speakers which mostly vary between half space and full space radiation?

I am not sure I understand you: do you mean the baffle step? I am using a single full range driver in a sealed or ported bookshelf speaker sized box.
I want it to make it sound as good as possible without EQ, then EQ.

I will compare it with the WD4, and if it is not pleasant to listen to, I will scrap it. At the moment good detail, forward sounding and lacks bass.

There is a diagram in the link below: it looks like the energy of the low frequencies 'leaks' around the speaker and causes a loss of sound energy: the higher frequencies diffract around the baffle edges or are projected forward.

https://speakerdesignworks.com/bafflestep.html
 
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Good choice, a full range speaker may become narrower than 180 degrees (baffle angle) at higher frequencies, somewhat similar to a waveguide. Otherwise the shape of the cabinet should be chosen to get along with the room walls. It helps to consider all frequencies when you go close to walls.
I have never heard a group play with their back against the wall, nor a singer
resting against the far wall. It stands to reason, then, that music will sound more natural when it emanates from somewhere in the room.
It should be possible to ignore the wall when there are no reflections related to imaging casting from it, and performer placement can cut through and behind the wall as needed. If there are imaging related reflections then you will hear the wall and won't be able to ignore it.
 
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Here is the prototype. You may recognize the open baffle with sides speaker from earlier. Closing off the open side of the speaker resulted in noticeably better bass. The concept is now proven, looking for a design with a slotted enclosure. Maybe like this one:

https://www.crutchfield.com/S-rjOh8PS3hSD/p_772P4N/Audioengine-P4N.html

Note the helpful "do not drop labelling": the speaker did fall off its stand with no damage at all, which is a feature.

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The speaker has to be quite compact, so I am basing the design on my existing C4B open back speaker. Testing shows great promise, with good bass, if I may say so myself. The drawing is completed in 3D and the dimensions are approximate.

I will have to move the speaker down a little bit as it looks too close to the top part of the enclosure. As the diagram shows, a slot will be introduced at the bottom. The front is to be covered fully with a grille cloth and the speaker driver will be recessed. I like the dimensions and size of the speaker.

The driver is the Pioneer car door speaker pictured earlier.

2023-01-25 2:40 pm 2023-01-25 2:40 pm #32
Choosing the drivers: So there is a set of Pioneer speakers for sale at the equivalent of $12 per pair. The woofer section was smooth and clear, the tweeter was awful so I actually cut it out, and mounted the woofer on an open baffle, I does fine with EQ but then these were made for door-mounting (Car door that is, although a room door.. that would be interesting)

https://www.diyaudio.com/community/threads/are-cardboard-enclosures-any-good.394837/page-2


Cardboard enclosures can be very good. Wood is better, it would be. :)
 
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Listening to the latest prototype is an amazing experience. The clarity is better than I have heard before, across several frequencies, and I hear instruments and voices never heard before on the same tracks. The bass is smooth and undistorted, Of course a little EQ was used to compensate for the loudness effect at 75 dB or so, I never can listen very loud anymore. Powered by the TEA 2025, and sourced from a smart phone over Bluetooth 5.

Initially I was disappointed with the bass, but a creating a makeshift slot by moving the back panel outwards, leaving a gap between the top of the speaker and the rear panel created the effect I wanted. On the final version a slot at the rear panel or front panel should create the same effect. With different thicknesses, the sound on the final version may have to be adjusted further. Coincidentally, the dimensions of the speaker, I call CS-7 for brevity, is similar to the BBC LS3/5A but of course has no crossover at all, as a result of my hearing what a direct crossover-less connection can sound like.

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The front panel needs to be made thicker so it can be fastened with screws instead of masking tape.