Radical Speaker Design - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 27Likes
Reply
 
Thread Tools
post #1 of 31 Old 02-26-2019, 05:15 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Radical Speaker Design

I am posting information about a pair of speakers that I have designed and built by myself. I am doing this because there are innovative design elements that I feel should be applied to consumer speakers. I am happy to host listening sessions for interested parties. I live in the Northern Virginia area, and hopefully I'll have 15 posts soon and be able to PM.

The basic design philosophy for this speaker was that baffle diffraction, ceiling reflections, floor reflections, and front wall reflections should be reduced drastically, while lateral reflections should be maintained. As such, I refer to this design as the "Radical 1" or "RaDCL 1" since they are "Reflection and Diffraction Controlling Loudspeakers". They are also different from any other speaker I've ever seen, thus giving the name a double meaning. They differentiate themselves even from other line arrays, since the are a 4-way design utilizing a fully passive crossover without the need for large amounts of equalization, and the combination of the AMT tweeter and close spacing between the mids prevents comb filtering common to most line array speakers.

It's difficult for our brains to differentiate the secondary sounds we hear coming from near our speakers from the original sound. These diffraction and reflection sources rob us of the detail in the recordings we play, and probably contribute to the perception that the sound is originating from the speakers, rather than coming from an instrument in a performance space.

In contrast, the lateral reflections can be differentiated from the original source, and provide us with a sense of envelopment. These are a benefit rather than a detriment, enhancing our perception of the music, and giving it a more lifelike quality.

The speakers themselves are a 4-way passive design, standing 5'4" tall, 20.5" wide, but only 4.5" deep. This form factor was chosen for on-wall placement, without creating interference between the direct sound and reflection off the wall, because the speakers are so wide and shallow. The internal volume is limited, which in turn limits the bass response. However, it's become clear that in-room bass is better addressed by using multiple subwoofers, with their locations chosen to mitigate standing waves (not necessarily placed where the left and right speaker are). I supplement these speakers with 2 separate 12" high output subwoofers, which cover frequencies below 100 Hz.

The speakers are quite efficient (about 94.5 dB @2.83V) and offer substantial power handling, resulting in clean, dynamic sound even when listening at high levels. At 100 hz, they should reach 105 dB before the woofers move past their linear range. However, floor and ceiling reflections contribute substantially to the loudness we perceive from most speakers, so these must be played a little louder (I'd estimate 4 to 5 dB) to reach the same perceived loudness. Still, they have no problem playing way louder than I should ever actually listen to music, and hearing damage could easilly be achieved if one were not careful, since there is little evidence of how loud they are playing. Earl Geddes has shown that diffraction is a major contributor to what people perceive as distortion related to loudness.
Attached Thumbnails
Click image for larger version

Name:	IMG_8072_Crop.jpg
Views:	454
Size:	879.1 KB
ID:	2531500   Click image for larger version

Name:	IMG_8076_Crop.png
Views:	515
Size:	1.06 MB
ID:	2531512   Click image for larger version

Name:	IMG_8075_Crop.png
Views:	459
Size:	985.0 KB
ID:	2531514  

Last edited by spkr_diy; 02-26-2019 at 05:26 PM.
spkr_diy is offline  
Sponsored Links
Advertisement
 
post #2 of 31 Old 02-26-2019, 05:37 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
These speakers present a significant challenge to measure. A substantial distance is required for the drivers to fully integrate, with appropriate relative levels. As such, I decided NOT to try to eliminate reflections in the measurements as most others do. Instead, I measured them where I use them: up against the wall. My speaker measurements all include the front wall reflection, and the floor and ceiling reflections. Most speakers would suffer pretty substantial interference problems if their measurements included reflections off the front wall, floor, and ceiling. But since these were designed to reduce the impact of those reflections, a nice result is possible anyway. Still, the measurements must be considered in context (which is always the case).

All these measurements were taken at a distance of about 6 feet from the LEFT speaker, at tweeter height. For the first picture, the mic was placed directly between the speaker and my listening position. The response is gated, with no other smoothing. The impulse response shows the floor reflection at about 2.5-3 ms delay, and the ceiling reflection at a 4 ms delay. A lateral reflection is visible at 7.5 ms, but is excluded from the gate.

The second picture supplements the measurement described above with 2 more measurements. These measurements are pointed where someone would be sitting if they were 3 seats away from center to the left (blue) and right (green). For reference, my seating is about 11 feet back from the speakers, and these seats are about 11 feet apart. If my speakers pointed straight out from the wall (which they don't) these would be at about 0 (blue) and 45 degrees (green), with the main listening position near 22.5 degrees (red).

The 3rd picture shows the impact of changing the gating of the measurement pointed to the main listening position to exclude the direct sound, but include both the floor and ceiling reflections. Similarly, the 4th picture excludes the direct sound, but captures a single lateral reflection off the left wall.

The final picture utilizes the frequency-dependent gating feature in Holm impulse that aims to approximate our perception of the sound. Since lower frequencies use a longer gating, they capture more reflections, which contribute to increased variance, with higher peaks. The slanted frequency response is natural, and speakers that measure flat in an anechoic chamber typically show such a trend when measured in-room.
Attached Thumbnails
Click image for larger version

Name:	Seating_Direction_Measurement_Ear_Height_2yds_ms.png
Views:	139
Size:	174.7 KB
ID:	2531516   Click image for larger version

Name:	Azimuthal_Measurements_Ear_Height_2yds_ms.png
Views:	134
Size:	192.1 KB
ID:	2531518   Click image for larger version

Name:	Seating_Direction_Measurement_Ear_Height_2yds_ms_FloorCeilingReflection.png
Views:	113
Size:	175.3 KB
ID:	2531520   Click image for larger version

Name:	Seating_Direction_Measurement_Ear_Height_2yds_ms_WallReflection.png
Views:	110
Size:	176.4 KB
ID:	2531522   Click image for larger version

Name:	Seating_Direction_Measurement_Ear_Height_2yds_ms_FreqDepGating.png
Views:	122
Size:	176.9 KB
ID:	2531528  

Ryanosaur likes this.

Last edited by spkr_diy; 02-26-2019 at 05:46 PM.
spkr_diy is offline  
post #3 of 31 Old 02-27-2019, 12:35 PM
Advanced Member
 
Vergiliusm's Avatar
 
Join Date: Aug 2002
Location: The Land of Enchantment
Posts: 603
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 223 Post(s)
Liked: 415
Return of the wide baffle--interesting design. Nice build. Just wiring up the drivers alone would be very time consuming.

The wider baffle would lower the baffle step. Did you have any issues with the compensation? Also, wouldn't you want larger mids and woofers to better control directivity?

Most importantly, how do they sound?

"Rock and roll is alive and alright" Sloan
Vergiliusm is offline  
Sponsored Links
Advertisement
 
post #4 of 31 Old 02-27-2019, 03:28 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by Vergiliusm View Post
Return of the wide baffle--interesting design. Nice build. Just wiring up the drivers alone would be very time consuming.

The wider baffle would lower the baffle step. Did you have any issues with the compensation? Also, wouldn't you want larger mids and woofers to better control directivity?

Most importantly, how do they sound?
Wiring up the drivers was fairly time consuming. By the time I was done I felt like I should have had a robot or something instead of a speaker.

I didn't have any problems with baffle step. The speaker always radiates into pi-space. Sometimes I think of it as a 180 degree horn. In order to achieve that, the depth has to be a tiny fraction of the width. I didn't want them to be ridiculously wide, so they had to be very shallow. The tiny depth is part of what led to the tiny woofers, because I needed something with very little Vas. Also, I wanted wide horizontal dispersion (besides the 180 degree horn aspect of integrating it into the wall), which requires smaller (or at least narrower) drivers. In order to create vertical directivity I used multiple small drivers, except for the tweeter. The tweeter is a single AMT with appropriate proportions, which doesn't suffer from the comb filtering so common among line arrays.

They sound great. I have had several musicians (who were also audio enthusiasts to varying degrees) tell me they have never heard a speaker system so accurately re-create the sound of instruments they play. The speakers are incredibly revealing of the source material, but in a completely non-fatiguing way. Also, they do a great job of re-creating the spatial cues on the recording. I don't intend to wax poetic about the sound. I'd rather have some others offer their impressions, and see if this approach is something that commercial speaker manufacturers ought to consider.
Ryanosaur likes this.
spkr_diy is offline  
post #5 of 31 Old 04-14-2019, 01:50 PM
Member
 
Join Date: Apr 2019
Posts: 123
Mentioned: 8 Post(s)
Tagged: 1 Thread(s)
Quoted: 118 Post(s)
Liked: 399
This thread deserves a lot more activity than it's received. I've heard the Radical on several occasions and it delivers on its design objectives. It has confirmed my belief, based on years of speaker design, that broad lateral dispersion is extremely important to realistic sound reproduction, and broad vertical dispersion is not necessary or even desirable, assuming it's not so narrow as to produce a "head in a vice" listening position. When I first saw the Radical, I was very skeptical that so many drivers could work together to produce a coherent, neutral sound. After listening to my own Philharmonic Audio test CD, I was convinced that the basic sound signature of the Radical was as neutral as any I had heard, and I also sensed a more immediate presentation of the recording venue, be it a studio or concert hall. The sound was simply cleaner, with superior differentiation of individual instruments and voices. To confirm that the Radical's response really was significantly truncated in the vertical plane, I knelt down to floor level and experienced a dramatic reduction in sound level. It was a little spooky. I was so fascinated with the Radical that I came back for a second listen, this time with a pair of my own Affordable Accuracy monitors. The AA's are perfectly conventional 2-way monitors, albeit with a complex crossover. They are as neutral as I could make them, and tonally there wasn't that much difference between them and the Radicals. But the AA's were simply "noisier" than the Radical. I had a much greater sensation that I was listening through the Radicals into the recording venue. Unlike my experience with so many controlled directivity speakers with wave guides or horns, I never sensed a constriction of the sound stage or any coloration. The Radical is obviously complex and wouldn't be practical in all listening environments, but in my opinion it would make a killer home theater speaker as well as a truly superior speaker for dedicated music listening. I was so enthusiastic about the Radical that I convinced a certain speaker manufacturer to fly in for a listen. He was as impressed as I was, and simply doesn't have the time or resources to make the Radical part of his lineup. I'm hoping that will change in the coming year. The Radical is an important step forward in speaker design and deserves wide exposure. Dennis Murphy

Last edited by PhilharmonicDennis; 05-04-2019 at 08:09 AM.
PhilharmonicDennis is online now  
post #6 of 31 Old 05-03-2019, 05:05 PM
Member
 
Join Date: Feb 2019
Location: Cali
Posts: 125
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 57 Post(s)
Liked: 179
I've already had my brain broke once today. This is cool, and I wish I understood it better! Thank you Dennis for directing our attention this way!!! @spkr_diy : Thank you for sharing, and not being afraid to innovate!!!

7.2: Marantz SR6012, Outlaw Model 2200 (L/C/R/SL/SR)
Philharmonic Phil 3 (L//R), BMR (C), BMR (SL/SR), Mini-Phil (RL/RR), Outlaw X-13
Sony XBR49X900F, Sony UBPX700
Ryanosaur is offline  
post #7 of 31 Old 05-03-2019, 09:51 PM
AVS Forum Special Member
 
head_unit's Avatar
 
Join Date: Sep 2005
Location: Sunny L.A.
Posts: 1,233
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 527 Post(s)
Liked: 269
Quote:
Originally Posted by spkr_diy View Post
Sometimes I think of it as a 180 degree horn. In order to achieve that, the depth has to be a tiny fraction of the width...
I'm not sure I follow-can you expand on that?
And I'd observe that in some way these are like an in-wall, getting rid of that first strong reflection. I had one house with in-walls and there was definitely a nice quality which I attributed to that. Good work!
head_unit is offline  
post #8 of 31 Old 05-04-2019, 07:31 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by head_unit View Post
I'm not sure I follow-can you expand on that?
And I'd observe that in some way these are like an in-wall, getting rid of that first strong reflection. I had one house with in-walls and there was definitely a nice quality which I attributed to that. Good work!
At high frequencies, the wall behind the speaker (I'm talking specifically about the thick side of the speaker here) is in an acoustic shadow. At lower frequencies, the sound pressure can bend around the baffle and head toward the front wall. However, since the wavelengths are long, and the speaker is shallow, the reflection is still in phase with the direct sound, and serves to reinforce that sound. That's how it effectively always radiates into pi space, and works like a 180 degree horn. If I pull the speaker even a few inches away from the wall, the path from the baffle edge to the front wall and back will no longer be in phase with the highest frequencies that bend around the baffle, and cancellation will occur. The thickest part of the speaker is only 4.5" deep (outside dimensions). It was a difficult criteria to accommodate, but a necessary one.
spkr_diy is offline  
post #9 of 31 Old 05-05-2019, 07:50 AM
AVS Forum Special Member
 
michael hurd's Avatar
 
Join Date: Nov 2007
Posts: 3,406
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 634 Post(s)
Liked: 669
With the 20.5 inch wide baffle, the baffle essentially behaves like a 180 degree horn down to 228 hz, into the schroeder region of most rooms. Placed near the wall like shown is a good design choice.



228 hz has a wavelength of 59.47 inches, sound wrapping the baffle edges and reflecting off the wall will be in phase. (<1/4 wavelength)

Ask your doctor if DIY is right for you. Side effects of DIY may include anxiety, elevated blood pressure, lightheadedness, rapid heartbeat, skeletal muscle flaccidity, euphoria, psychological dependence, insomnia, confusion, blurred vision, implusivity, uncontrolled or repeated movements.
michael hurd is offline  
post #10 of 31 Old 05-06-2019, 09:15 AM
Member
 
bcg27's Avatar
 
Join Date: Nov 2009
Location: MD
Posts: 171
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 23 Post(s)
Liked: 18
Quote:
Originally Posted by spkr_diy View Post
At high frequencies, the wall behind the speaker (I'm talking specifically about the thick side of the speaker here) is in an acoustic shadow. At lower frequencies, the sound pressure can bend around the baffle and head toward the front wall. However, since the wavelengths are long, and the speaker is shallow, the reflection is still in phase with the direct sound, and serves to reinforce that sound. That's how it effectively always radiates into pi space, and works like a 180 degree horn. If I pull the speaker even a few inches away from the wall, the path from the baffle edge to the front wall and back will no longer be in phase with the highest frequencies that bend around the baffle, and cancellation will occur. The thickest part of the speaker is only 4.5" deep (outside dimensions). It was a difficult criteria to accommodate, but a necessary one.
Do you have a plan for these speakers going forward? It sounds like maybe you are trying to license them to a speaker manufacturer but I for one would be very interested if a DIY design were released as I imagine these would carry a hefty price tag from a commercial source.
bcg27 is offline  
post #11 of 31 Old 05-06-2019, 06:25 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by bcg27 View Post
Do you have a plan for these speakers going forward? It sounds like maybe you are trying to license them to a speaker manufacturer but I for one would be very interested if a DIY design were released as I imagine these would carry a hefty price tag from a commercial source.
I don't have a specific plan for these speakers at the moment. I am not posting here to find someone to license the design to, though I do want to keep that option open. I am trying to influence the consumer speaker industry a little. A couple of the effective technologies in this speaker are rare or non-existent in consumer speakers.

1) If speakers are wide enough and shallow enough, on-wall placement can be a benefit rather than a detriment.

2) Vertical dispersion can be limited with a line array design variation without the usual problems of comb filtering, nor the need for EQ or numerous amplifier channels.

3) Large round-overs are effective at reducing diffraction.

I am currently working on another project to drive home that last point. I will be modifying a commercial speaker design. I hope to post about that in the next several weeks.
spkr_diy is offline  
post #12 of 31 Old 05-06-2019, 08:19 PM
M S
Member
 
M S's Avatar
 
Join Date: Jan 2012
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 21
The radicals look fascinating to me. I like that they are efficient, and though large, the slender profile compensates for that.

I would also be interested in a DIY option.

When you post about your current project maybe link to it on this thread so I will get an alert☺

Thanks for sharing.

Last edited by M S; 05-14-2019 at 11:13 AM.
M S is offline  
post #13 of 31 Old 05-07-2019, 12:23 PM
AVS Forum Special Member
 
Join Date: Mar 2015
Location: Ottawa, ON
Posts: 1,586
Mentioned: 23 Post(s)
Tagged: 1 Thread(s)
Quoted: 793 Post(s)
Liked: 647
Just a point for aesthetics - perhaps use black screws for the drivers rather than stainless steel ones.
sigpig is offline  
post #14 of 31 Old 05-07-2019, 03:37 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by sigpig View Post
Just a point for aesthetics - perhaps use black screws for the drivers rather than stainless steel ones.
I agree in theory. However, this project suffered a lot of delays due to other things having priority (job, wife, kids, house) and I refused to add to the delay to source the right color screws. Have you ever heard that "done is better than perfect"? It would be interesting to see how nice they could look. Mine look very industrial... but I'm perfectly happy with that.
spkr_diy is offline  
post #15 of 31 Old 05-11-2019, 02:31 AM
AVS Forum Special Member
 
Peter M's Avatar
 
Join Date: Sep 2000
Location: Sydney
Posts: 2,056
Mentioned: 13 Post(s)
Tagged: 1 Thread(s)
Quoted: 377 Post(s)
Liked: 302
Any thoughts on what you'd change if free of the depth constraint and mounting them flush in a baffle wall ?

Cheers,
Peter M is offline  
post #16 of 31 Old 05-11-2019, 09:38 AM
AVS Forum Special Member
 
kokishin's Avatar
 
Join Date: Sep 2006
Location: Silicon Valley
Posts: 2,059
Mentioned: 25 Post(s)
Tagged: 1 Thread(s)
Quoted: 1230 Post(s)
Liked: 1228
@spkr_diy

Your DIY speakers look amazing! What a labor of love.

Don't mean to go OT, but what is the center speaker in your 1st pic?

Denon AVR-X6200W, Outlaw Audio 7125 Amp, Oppo UDP-203, Oppo BDP-103, Amazon Fire TV Stick, Tivo Roamio Pro, Pioneer Elite Andrew Jones Dolby Atmos Enabled EFS-73 Fronts/EBS-73 Surrounds, Chane A2.4 Center, SVS SB-2000 Sub, Panasonic Plasma TH-58PX600
avsforum Members Atmos & Auro Configuration Spreadsheet
I'm just a caveman. Your modern world frightens and confuses me. RIP Phil Hartman
kokishin is online now  
post #17 of 31 Old 05-11-2019, 10:29 AM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by Peter M View Post
Any thoughts on what you'd change if free of the depth constraint and mounting them flush in a baffle wall ?

Cheers,
If not for the depth constraint, I might use a different tweeter, though the AST2560 has proven to be amazing. Most ribbons have a large enough transformer that they would be too deep for my cabinet. I originally had a different tweeter in mind (I think it was a Fountek) but eventually figured out that it wouldn't fit.

Unless there was a volume constraint (requiring low VAS woofers), I'd probably build it with a bigger woofer, too. I can't really justify it, since these go deep enough to cross to my subs, and they play plenty loud and clean. Sometimes we go overboard for our passions.
spkr_diy is offline  
post #18 of 31 Old 05-11-2019, 10:35 AM
AVS Forum Special Member
 
Shadowed's Avatar
 
Join Date: Mar 2014
Posts: 2,242
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 938 Post(s)
Liked: 909
I'll take 2 please....

Make that 3, one for center.
JohnnyWilkinson likes this.
Shadowed is offline  
post #19 of 31 Old 05-11-2019, 10:40 AM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by kokishin View Post
@spkr_diy

Your DIY speakers look amazing! What a labor of love.

Don't mean to go OT, but what is the center speaker in your 1st pic?
Thanks for the kind words.

The center speaker is a very old DIY speaker I made specifically to fit on the top of a CRT TV that had a very shallow top (about 4 inches). The crossover is pretty low, so the dispersion isn't as troubling as it would appear. There's a port on the left side where there would normally be a second woofer in a center channel. I have plans and parts to build a truncated version of the Radical speakers that will fit under the screen, but that project never makes it to the top of my priorities. I do all my critical listening in stereo, and will continue to do so if/when I finish the matching center channel. The center channel only gets used for movies, and what I've found is that you don't need perfection for movies, which are mostly about dialogue and effects.
spkr_diy is offline  
post #20 of 31 Old 05-11-2019, 10:46 AM
Senior Member
 
JohnnyWilkinson's Avatar
 
Join Date: Jan 2019
Posts: 398
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 309 Post(s)
Liked: 197
Quote:
Originally Posted by bcg27 View Post
Do you have a plan for these speakers going forward? It sounds like maybe you are trying to license them to a speaker manufacturer but I for one would be very interested if a DIY design were released as I imagine these would carry a hefty price tag from a commercial source.
+1

Would love to attempt a DIY project with this design for stereo listening.

---------------


My build thread
JohnnyWilkinson is offline  
post #21 of 31 Old 05-11-2019, 12:13 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by JohnnyWilkinson View Post
+1

Would love to attempt a DIY project with this design for stereo listening.
Thanks, I take that as a compliment. I definitely want more people to have speakers like this. You aren't the first to show interest in a DIY build. My honest assessment is that the speaker is too complicated for DIY. I don't mean that to be disparaging in any way. There are certainly others out there who could build them, and build them nicer than I did. But there's a thousand different ways to mess it up, and the wiring is way, way beyond your typical DIY build. Here's a pic of the guts, so people thinking DIY know a little bit about what that would entail.
Attached Thumbnails
Click image for larger version

Name:	Radical_Guts_small.jpg
Views:	76
Size:	678.7 KB
ID:	2565502  
spkr_diy is offline  
post #22 of 31 Old 05-13-2019, 05:36 PM
M S
Member
 
M S's Avatar
 
Join Date: Jan 2012
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 21
Quote:
Originally Posted by spkr_diy View Post
Thanks, I take that as a compliment. I definitely want more people to have speakers like this. You aren't the first to show interest in a DIY build. My honest assessment is that the speaker is too complicated for DIY. I don't mean that to be disparaging in any way. There are certainly others out there who could build them, and build them nicer than I did. But there's a thousand different ways to mess it up, and the wiring is way, way beyond your typical DIY build. Here's a pic of the guts, so people thinking DIY know a little bit about what that would entail.
Don't underestimate a dedicated DIYer. Its all series or parallel, just take a small section at a time. Give us a good schematic and it can be done. I always take care to label all terminations (and leads, if necessary).
Peter M likes this.
M S is offline  
post #23 of 31 Old 05-14-2019, 01:23 AM
AVS Forum Special Member
 
Peter M's Avatar
 
Join Date: Sep 2000
Location: Sydney
Posts: 2,056
Mentioned: 13 Post(s)
Tagged: 1 Thread(s)
Quoted: 377 Post(s)
Liked: 302
Prefab wiring looms ?
Peter M is offline  
post #24 of 31 Old 05-14-2019, 08:33 AM
AVS Forum Special Member
 
Shadowed's Avatar
 
Join Date: Mar 2014
Posts: 2,242
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 938 Post(s)
Liked: 909
This is definitely NOT too complicated for DIY and I am not sure why this wasn't posted in the DIY section... ?
Shadowed is offline  
post #25 of 31 Old 05-14-2019, 05:52 PM
Newbie
 
DDF600's Avatar
 
Join Date: Nov 2011
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 5
Very novel design, congratulations on pushing the boundaries of DIY!

I agree with Denis, after decades of DIY I also think broad lateral dispersion and narrow vertical are conducive to reducing colouration from the room, with one caveat. In small lively rooms, I find narrower lateral dispersion is beneficial to broaden the sweet spot and avoid large shifts in image with small shifts in listening location (listening to a DIY design right now with this purposeful feature). But yours aren't designed for that sort of application, so that was just a small qualifying aside.

Interestingly, Dr Toole posted at ASR recently that he is of the opinion that the floor bounce and ceiling bounce are natural conditions of listening in rooms (true), that we adapt to the sound of rooms (true: audiosciencereview.com/forum/index.php?threads/an-enticing-marketing-story-theory-without-measurement.7127/page-9#post-164402) and that its not a benefit to reduce vertical reflection effects. I'm not convinced of this last item given double blind test results posted in AES clearly showing the audibility of the floor bounce. While floor bounce can help give a "they are here" effect, it must certainly detract from a "you are there" effect and I'm convinced of this based on my own designs. I also think the floor bounce leans out the upper bass relative to what's expected from most recordings and that line sources, large panels or designs with vertical row of woofers (e.g. Paradigm, Revel) reduce this effect to good purpose, as does your design.

Boston Acoustics used to specialize in on-wall shallow box designs back in the early 80s for the same reason as you, but they were mostly 2 ways and didn't address the floor or ceiling bounce. I recall one design that attempted to do this by placing the drivers at the floor with a tilted baffle and a ramp in front of the baffle in the floor. Your design is "a bit" more elegant.

Note that the dimensions in a home listening room are too small to provide true "envelopment" from broad lateral dispersion (see Greisinger), but it certainly does help with "spaciousness", which is a bit different. Envelopment is possible, but requires more radical intervention audiosciencereview.com/forum/index.php?threads/an-enticing-marketing-story-theory-without-measurement.7127/page-19#post-172417

Another thing to consider is that a broad baffle speaker may have a different in room tonal balance than a standard narrow baffle speaker, for the same on axis, since the off axis radiation will be so different and we tend to integrate the on and off axis more the lower we go in frequency. I looked at this for the Grimms: diyaudio.com/forums/multi-way/282859-analysis-pros-cons-wide-baffles-study-grimm-ls-1-a.html

OTOH, it was very interesting that the designer of the Dutch&Dutch8C's (cardiod) felt that he didn't have to voice his speakers for the directivity difference between cardiod and standard monopole speakers: audiosciencereview.com/forum/index.php?threads/soundstage%E2%80%99s-review-of-dutch-dutch%E2%80%99s-8c.7308/page-7#post-173726

All in all, your speakers look very appealing and something I would love to hear.

Question if you don't mind elaborating: were the 4 drivers off center used to try to help clean up the forward lobe, reducing vertical nulls or hot spots by making a more continuous line source?
DDF600 is offline  
post #26 of 31 Old 05-15-2019, 12:08 PM
Senior Member
 
JohnnyWilkinson's Avatar
 
Join Date: Jan 2019
Posts: 398
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 309 Post(s)
Liked: 197
Quote:
Originally Posted by spkr_diy View Post
Thanks, I take that as a compliment. I definitely want more people to have speakers like this. You aren't the first to show interest in a DIY build. My honest assessment is that the speaker is too complicated for DIY. I don't mean that to be disparaging in any way. There are certainly others out there who could build them, and build them nicer than I did. But there's a thousand different ways to mess it up, and the wiring is way, way beyond your typical DIY build. Here's a pic of the guts, so people thinking DIY know a little bit about what that would entail.
Honestly, this doesn't scare me. I've built PC's from scratch, back in the day. And I don't mean piecing together components you can buy, I mean building everything DIY including all the circuit boards.

I think people would pay for the DIY schematics of this one. Including myself :-)

---------------


My build thread
JohnnyWilkinson is offline  
post #27 of 31 Old 05-15-2019, 03:58 PM
M S
Member
 
M S's Avatar
 
Join Date: Jan 2012
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 21
I took the liberty to link this thread on PE Techtalk to help broaden exposure to your design.
http://techtalk.parts-express.com/fo...speaker-design

One of the designers there (Wolf) suggested the Peerless dome woofers may be useful in your design. I don't know how they compare since you didn't mention what woofer you are using. Maybe you already considered them.

https://www.parts-express.com/peerle...ofer--264-1684

https://www.parts-express.com/peerle...-ohm--264-1484
M S is offline  
post #28 of 31 Old 05-16-2019, 08:00 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by DDF600 View Post
Very novel design, congratulations on pushing the boundaries of DIY!

I agree with Denis, after decades of DIY I also think broad lateral dispersion and narrow vertical are conducive to reducing colouration from the room, with one caveat. In small lively rooms, I find narrower lateral dispersion is beneficial to broaden the sweet spot and avoid large shifts in image with small shifts in listening location (listening to a DIY design right now with this purposeful feature). But yours aren't designed for that sort of application, so that was just a small qualifying aside.
I understand your concern about a small lively room. Of course, there's always the option to treat a lively room to make it more neutral. That would probably be my preferred tactic, because you can treat first reflection points while leaving higher order reflections be. Using horns or waveguides to reduce dispersion typically requires reducing the higher order reflections in order to treat the first reflection points, which is sort of like throwing the baby out with the bath water... at least where lateral reflections are concerned. Geddes tries to address this by angling his speakers with a great amount of tow-in. He's convinced that exaggerated first-order contralateral reflections aren't detrimental to imaging. Personally, I have one bit of treatment in my room, and it's for an annoying contralateral reflection.


Quote:
Originally Posted by DDF600 View Post
Interestingly, Dr Toole posted at ASR recently that he is of the opinion that the floor bounce and ceiling bounce are natural conditions of listening in rooms (true), that we adapt to the sound of rooms (true: audiosciencereview.com/forum/index.php?threads/an-enticing-marketing-story-theory-without-measurement.7127/page-9#post-164402) and that its not a benefit to reduce vertical reflection effects. I'm not convinced of this last item given double blind test results posted in AES clearly showing the audibility of the floor bounce. While floor bounce can help give a "they are here" effect, it must certainly detract from a "you are there" effect and I'm convinced of this based on my own designs. I also think the floor bounce leans out the upper bass relative to what's expected from most recordings and that line sources, large panels or designs with vertical row of woofers (e.g. Paradigm, Revel) reduce this effect to good purpose, as does your design.
My thoughts on the floor bounce largely agree with yours.

Quote:
Originally Posted by DDF600 View Post
Boston Acoustics used to specialize in on-wall shallow box designs back in the early 80s for the same reason as you, but they were mostly 2 ways and didn't address the floor or ceiling bounce. I recall one design that attempted to do this by placing the drivers at the floor with a tilted baffle and a ramp in front of the baffle in the floor. Your design is "a bit" more elegant.
I can't find any images of these BA on-wall speakers. Do you have a model number or anything? I'd be interested to see what they did.

Quote:
Originally Posted by DDF600 View Post
Note that the dimensions in a home listening room are too small to provide true "envelopment" from broad lateral dispersion (see Greisinger), but it certainly does help with "spaciousness", which is a bit different. Envelopment is possible, but requires more radical intervention audiosciencereview.com/forum/index.php?threads/an-enticing-marketing-story-theory-without-measurement.7127/page-19#post-172417
I found the Greisinger paper quickly and easily, thanks for referencing it. I believe I have read it before, but it's hard to keep all my sources straight. It's interesting to compare a speaker such as I have designed to an omni-directional speaker. Both will have similar levels of lateral reflections for a given source level. However, the medial sound energy of the omni-directional speaker is re-inforced by the floor and ceiling reflections. In my estimation, the reinforcement differential is about 4 or 5 dB between my speaker and an omni-directional speaker. That means that the ratio of medial to lateral sound is 4-5 dB lower for my speaker, and inter-aural cross-correlations are similarly decreased (and IAD preferred by Greisinger as well). Yet my speakers are perceived as incredibly detailed. This is probably due to the binaural unmasking capabilities of our auditory systems, that allow us to focus on the sounds coming from in front of us despite interference from the sides.

Quote:
Originally Posted by DDF600 View Post
Another thing to consider is that a broad baffle speaker may have a different in room tonal balance than a standard narrow baffle speaker, for the same on axis, since the off axis radiation will be so different and we tend to integrate the on and off axis more the lower we go in frequency. I looked at this for the Grimms: diyaudio.com/forums/multi-way/282859-analysis-pros-cons-wide-baffles-study-grimm-ls-1-a.html

OTOH, it was very interesting that the designer of the Dutch&Dutch8C's (cardiod) felt that he didn't have to voice his speakers for the directivity difference between cardiod and standard monopole speakers: audiosciencereview.com/forum/index.php?threads/soundstage%E2%80%99s-review-of-dutch-dutch%E2%80%99s-8c.7308/page-7#post-173726
As Dennis noted, the spectral balance between my speaker and his AA was very similar. It might be interesting to contrast the transfer function of my woofer crossover with the measurements I've made.

Quote:
Originally Posted by DDF600 View Post
All in all, your speakers look very appealing and something I would love to hear.

Question if you don't mind elaborating: were the 4 drivers off center used to try to help clean up the forward lobe, reducing vertical nulls or hot spots by making a more continuous line source?
Yes, the off-center drivers create a more continuous line source. They are only off-center because there is a higher frequency driver that requires the same vertical position, and takes priority for horizontal positioning. The reason to do this is to keep sidelobes down. If those off-center drivers were removed, the mainlobe would actually get narrower, but the sidelobes would increase, and vertical reflections would increase as well.

If you find yourself in the DC /NoVA area, then please contact me.

BTW, congratulations on making your first post after more than 7 years.

Last edited by spkr_diy; 05-16-2019 at 08:06 PM.
spkr_diy is offline  
post #29 of 31 Old 05-19-2019, 01:54 PM
Newbie
 
DDF600's Avatar
 
Join Date: Nov 2011
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 5
Quote:
Originally Posted by spkr_diy View Post
I understand your concern about a small lively room. Of course, there's always the option to treat a lively room to make it more neutral. That would probably be my preferred tactic, because you can treat first reflection points while leaving higher order reflections be. Using horns or waveguides to reduce dispersion typically requires reducing the higher order reflections in order to treat the first reflection points, which is sort of like throwing the baby out with the bath water... at least where lateral reflections are concerned. Geddes tries to address this by angling his speakers with a great amount of tow-in. He's convinced that exaggerated first-order contralateral reflections aren't detrimental to imaging. Personally, I have one bit of treatment in my room, and it's for an annoying contralateral reflection.
I wanted a solution that didn't affect the look of the listening space, and Toole/Olive found that so long as the reflection is similar is spectrum to incident, its less easily heard as a disparate problem (binaural listening, as you mentioned). Combing these two, controlled dispersion helps quite a bit. I also use toe-in, but too much with the wrong design can throw a image with some significant irregularities in the spectrum.

Quote:
Originally Posted by spkr_diy View Post
I can't find any images of these BA on-wall speakers. Do you have a model number or anything? I'd be interested to see what they did.
Boston A100's, right around the time the "Alison Effect" became popularized in HiFi circles
canuckaudiomart.com/details/176611-boston_acoustics_a100_series_ii/images/226192/

Quote:
Originally Posted by spkr_diy View Post
As Dennis noted, the spectral balance between my speaker and his AA was very similar. It might be interesting to contrast the transfer function of my woofer crossover with the measurements I've made.
It would be wonderfully handy to have some psychoacoustic data showing how reflections change tonal balance (and how to compensate direct sound as a result) and not just the existing data (that I know of) in artificial conditions of anechoic chamber and single virtual reflection reproduced by a speaker (which doesn't factor in true T30-T200 energy). Until then, we voice.

Quote:
Originally Posted by spkr_diy View Post
If you find yourself in the DC /NoVA area, then please contact me.
I don't travel there but thanks for the kind offer.

Quote:
Originally Posted by spkr_diy View Post
BTW, congratulations on making your first post after more than 7 years.
LOL, stalker!
DDF600 is offline  
post #30 of 31 Old 05-22-2019, 06:44 PM - Thread Starter
Member
 
spkr_diy's Avatar
 
Join Date: Jul 2007
Location: Chantilly, VA
Posts: 47
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
Liked: 52
Quote:
Originally Posted by M S View Post
The radicals look fascinating to me. I like that they are efficient, and though large, the slender profile compensates for that.

I would also be interested in a DIY option.

When you post about your current project maybe link to it on this thread so I will get an alert☺

Thanks for sharing.
As requested, here's a link to my much smaller, simpler, less expensive project for modifying a commercial bookshelf speaker of rare value from Sony:

https://www.avsforum.com/forum/89-sp...ny-ss-cs5.html
spkr_diy is offline  
Sponsored Links
Advertisement
 
Reply Speakers

Tags
array , directivity , diy , radical , speaker

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off