Either that or diffraction (and sometimes combination of both).
Luckily it's a dip, so they are hard to detect.
Pretty nice directivity btw.
tktran303: actually my thoughts as well. I will keep those 2way prototypes for a few months so I will have a lot of time to get to know their sound and sort out my impressions. I already started planning of 3way 21W+ new 15W Classic + 9800. Tilted baffle, all LR2 filters, that is the initial target.
Some points are of a theoretical or rhetorical nature, audibility of certain distortion components, their levels, those are not easy topics.
8" 2way WG
Pros:
8" 3way 8+5or4+1
Pros:
I do not see the clear winner here.
Quire recently I finished ClassIllu project 18W/8545K00 + 6600 directly radiating. And I was more then happy with the results. My listening room is 5x6, acoustically treated on the sides and between loudspeakers, so this is part of the equation and the overall result and impression. I sold the speakers to friend of mine, he has the speakers in normal smaller living room, and he is very happy with the sound, with its detail transparency and drive
As I tend to focus on technical aspects I like 8+WG concept due to its off axis performance on the paper, but when I listen to the systems, I am happy with both concepts.
Both concepts can be designed to bring the good sound....
There were a lot of projects I created and/or listened and still I am not decided on the benefits of the waveguides.
Some points are of a theoretical or rhetorical nature, audibility of certain distortion components, their levels, those are not easy topics.
8" 2way WG
Pros:
- off axis performance, directivity in the critical ~1-6kHz range
- simpler crossover
- no crossover in 300-600Hz region, no vertical issues coming from non-coincident drivers
- due to off axis performance most likely easier to setup in the room, and requiring less acoustical treatment in ~500-6000Hz region only. Bass and lower midrange room modes will interfere anyway.
- might be easier to tune, to dial in, to find the balance, due to WG directivity
- WG itself (if well designed) mitigates the diffractions, and if baffle edges have ~30mm radius (and baffle is not much wider then WG! - something like rule of thumb I found out empirically), the diffractions are basically non-existent
- 8" has two difficult duties at once, bass and midrange
- most of the 8" drivers do not have perfect distortion >500Hz
8" 3way 8+5or4+1
Pros:
- dedicated midrange driver, lower excursion
- likely lower distortion in 500-2000Hz thank to dedicated midrange
- tweeter can be likely crossed over higher, close to 3kHz, which lowers the distortion at higher listening levels
- power response in 1-6kHz not monotonically declining due to tweeter off axis wide radiation
- added crossover in ~400Hz region brings troubles in vertical plane
- more complex crossover, more components
- more demanding to room acoustics, wider radiation in 500-6000Hz region might be an issue requiring speaker placement further from the walls, addressing the first reflections, toe in,....
- might be more difficult to find the right balance due to wide radiation above midrange/tweeter Fc
- designer must take care of tweeter placement and baffle diffractions. This usually brings complications when diffraction is in Fc region
- 3way is generally more complex to measure, design and to find the right balance. Woofer/midrange crossover is in the region where in room measurements and techniques start to be inadequate, designer skill and experiences are required.
I do not see the clear winner here.
Quire recently I finished ClassIllu project 18W/8545K00 + 6600 directly radiating. And I was more then happy with the results. My listening room is 5x6, acoustically treated on the sides and between loudspeakers, so this is part of the equation and the overall result and impression. I sold the speakers to friend of mine, he has the speakers in normal smaller living room, and he is very happy with the sound, with its detail transparency and drive
As I tend to focus on technical aspects I like 8+WG concept due to its off axis performance on the paper, but when I listen to the systems, I am happy with both concepts.
Both concepts can be designed to bring the good sound....
There were a lot of projects I created and/or listened and still I am not decided on the benefits of the waveguides.
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Where do you get that from?
I have seen plenty of 8 inch woofers that have great distortion performance.
In fact quite a few will beat any fancy expensive 5 or 6 inch with ease.
I would only never use a full-range system because of those pesky room modes.
The biggest disadvantage is just the size for some people.
The main difference between a 3-way and a 2-way, is that a 2-way will naturally beam more. Which I think is a good think in most rooms, but it also depends on taste.
I would pick a 2-way system with a 8 inch woofer any time combined with a multi-sub system. Obviously this can also have the same looks as a 3-way system.
That way only one additional sub (ideally two) is required in room.
b_force: I wrote "most of the 8" drivers" which translates into....
1. breakups at lower frequency compared to 5or4inch drivers => HD components mirroring to lower frequencies
2. 8" drivers are likely often optimized by manufacturers for woofer duty then for midwoofer duty
3. from 8" in 2way I want also bass, good bass. Which makes it harder to find something suitable. In the case system is planned to be used with the subwoofer, it makes choice of midwoofer easier and opens more options
4. of course there are exceptions and there are likely good options in PA drivers like B&C, Faital Pro etc.
5. Finding suitable 8" could be harder then finding suitable midrange to 3way project.
8" drivers that came to my mind and that are likely very good option for fullrange (meaning also doing bass) 2way:
Scan Speak 21WE - well, there is not much to object to this drivers, except the price
Scan Speak Discovery 8"
Purifi 8inch - same as above
Peerless NE225W - unfortunately NLA
Wavecor WF223BD
Dayton RS225P
1. breakups at lower frequency compared to 5or4inch drivers => HD components mirroring to lower frequencies
2. 8" drivers are likely often optimized by manufacturers for woofer duty then for midwoofer duty
3. from 8" in 2way I want also bass, good bass. Which makes it harder to find something suitable. In the case system is planned to be used with the subwoofer, it makes choice of midwoofer easier and opens more options
4. of course there are exceptions and there are likely good options in PA drivers like B&C, Faital Pro etc.
5. Finding suitable 8" could be harder then finding suitable midrange to 3way project.
8" drivers that came to my mind and that are likely very good option for fullrange (meaning also doing bass) 2way:
Scan Speak 21WE - well, there is not much to object to this drivers, except the price
Scan Speak Discovery 8"
Purifi 8inch - same as above
Peerless NE225W - unfortunately NLA
Wavecor WF223BD
Dayton RS225P
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@Pida
Right, these days I don't make much difference anymore between PA and hifi.
The performance is so similar.
But there are still so many 8 inch hifi woofers that are great.
But again, I personally think it's harder to do a full-range 2-way, instead of splitting it up with subwoofers.
Mostly because I see very little practical disadvantages these days.
Anyway, I can give some longer list of great 8 inch woofers, because there are many more.
Btw, the Dayton RS225 was tested recently in Hobby Hifi, still a great woofer after all those years. Especially the 8 ohm version has very little issues.
Right, these days I don't make much difference anymore between PA and hifi.
The performance is so similar.
But there are still so many 8 inch hifi woofers that are great.
But again, I personally think it's harder to do a full-range 2-way, instead of splitting it up with subwoofers.
Mostly because I see very little practical disadvantages these days.
Anyway, I can give some longer list of great 8 inch woofers, because there are many more.
Btw, the Dayton RS225 was tested recently in Hobby Hifi, still a great woofer after all those years. Especially the 8 ohm version has very little issues.
RS225-4 @ 90dB
RS225-8 @ 90dB
For the full article you have to buy Hobby Hifi 2/3-2023
And no, it's obviously not as low as some much more expensive drivers, but extremely workable.
(at the same time, a lot better than woofers that are a more expensive as well)
Btw, this is NOT the P variant, I think the P variant performs a little less.
Not sure why.
edit: looks like the break-up peak is a lot lower at the P variant.
That's unfortunately, because I think they look a lot better
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Today I continued listening and tuning of the loudspeakers.
I got rid of resistor in tweeter section doing the attenuation, and replaced it with series RC in parallel to tweeter and increased overall tweeter level by 0.5-1dB. This showed to be the right step.
As the result is very satisfactory so far, I will plan making final cabinets, with optimized baffle around tweeter to improve mild 2300Hz diffraction and smooth out off axis responses.
18kHz peak needed needed just partial compensation. As I expected mild lift of trebles above 5kHz is not a problem.,
After ClassIllu 2way with 18W/8545K00, this is again the moment I am impressed with Scan Speak Classic driver. I have been working and listening to 18W Revelator, 18WU Illuminators, Satori MW16P MW19P WO24P, SB SB17xx, NE 225W,.....and in 7-8inch cathegory Classic drivers just shine. They were not easiest to work with, I takes several iterations of amount of damping material adjustment, port tuning adjustment, and of course crossover changes, yet very rewarding experience.
I got rid of resistor in tweeter section doing the attenuation, and replaced it with series RC in parallel to tweeter and increased overall tweeter level by 0.5-1dB. This showed to be the right step.
As the result is very satisfactory so far, I will plan making final cabinets, with optimized baffle around tweeter to improve mild 2300Hz diffraction and smooth out off axis responses.
18kHz peak needed needed just partial compensation. As I expected mild lift of trebles above 5kHz is not a problem.,
After ClassIllu 2way with 18W/8545K00, this is again the moment I am impressed with Scan Speak Classic driver. I have been working and listening to 18W Revelator, 18WU Illuminators, Satori MW16P MW19P WO24P, SB SB17xx, NE 225W,.....and in 7-8inch cathegory Classic drivers just shine. They were not easiest to work with, I takes several iterations of amount of damping material adjustment, port tuning adjustment, and of course crossover changes, yet very rewarding experience.
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Thank you Petr for publishing measurements and auditory findings on your website:
https://pkaudio.webnode.cz/
I also enjoyed your documentation of the Scan-Speak 18W/8545K-00 to D3004/6600 classic two way, albeit with low crossover points and facetted cabinets, and full measurements.
https://pkaudio.webnode.cz/classillu/
We know it's hard to translate what one hears and perceives to words (written description) or graphics (measurements) but you are going an honest job!
Keep up the great work!
If you can, and enjoy, please donate a coffee or tea to help Petr.
https://pkaudio.webnode.cz/
I also enjoyed your documentation of the Scan-Speak 18W/8545K-00 to D3004/6600 classic two way, albeit with low crossover points and facetted cabinets, and full measurements.
https://pkaudio.webnode.cz/classillu/
We know it's hard to translate what one hears and perceives to words (written description) or graphics (measurements) but you are going an honest job!
Keep up the great work!
If you can, and enjoy, please donate a coffee or tea to help Petr.
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