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Multi-Way Conventional loudspeakers with crossovers

Ekta Mk2? Beyond the Epos ES 22s
Ekta Mk2? Beyond the Epos ES 22s
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Old 14th November 2017, 02:56 AM   #31
LineSource is offline LineSource  United States
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Only measurements at different angles on the final speaker will produce accurate SPL curves, but simulators provide excellent information for early decisions. Diffraction simulation of different baffle designs (large edge radius; truncated pyarmid, small edge radius narrow box) help the designer select the desired sonic signature. Baffle/room simulators cover speaker placement and room gain.

Attached simulation shows in-room bass for two 8" woofers(like Sony SS-AR1). (WxHxD: 320 x 1055 x 450 mm)
The Kairos and SB10 use one 10" woofer. A 12" woofer is sometimes mounted on the side panel.

SB Acoustics 3 way
one = $366 drivers + $90 crossover
1" SB26STCN-C000-4 $40
5" Satori MR13P-4 $132
2 x 8'' SB23NRXS45-8 2x $94

==== Sd cone area ====
18" 1220 cm2
15" 855 cm2
12" 530 cm2
10" 345 cm2
8" 225 cm2
7" 180 cm2
6" 125 cm2
5" 85 cm2
Attached Images
File Type: jpg Large Radius .jpg (202.8 KB, 132 views)
File Type: jpg Truncated Pyramid1 .jpg (118.7 KB, 135 views)
File Type: jpg Tall Narrow Box.jpg (211.3 KB, 133 views)
File Type: jpg EKTA2 baffle room.jpg (162.1 KB, 133 views)
File Type: jpg SonyKlone.JPG (227.4 KB, 133 views)
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Old 14th November 2017, 02:38 PM   #32
lupo 1 is offline lupo 1  Italy
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Default response to andy19191 and LineSource - woof woof!

Andy 19191

I'd sort of avoided the notion of a sub at all costs: partly because I didn't realise that I don't need an AV receiver to make the connection. It seems, instead, that I can simply use a sub's high level inputs to connect to the existing outputs on my amp for the es22's, duh! the other reason was a comment by someone, way back in time, to the effect that he worried his es22's transient response might be too good for a sub to keep up with ...(?) ... (!)

So thanks for gently nudging me forward. Not too clever at interpreting graphs, as I'm sure you've figured already, but I take it that thumbnail 1 = bad and thumbnail 2 = good and just to let you know that it's still me, here's a really silly question for you:

If, as you suggest (and I've heard it said before), a sub is better thought of as a means for controlling room response, can a sub do this AND act as substitute for a 10/12" single woofer (or 2 x 8" ones), or would it be better to see it as more effective when working alongside balanced 3 way 12/10 - 5/6 - 1 speakers such as the SBA 10?

Thanks for the tip re EQ room wizard - even if in the end I just use my ears - which, by now, are probably in much better nick than my brain.

LineSource and andy19191

LineSource, Thanks for making it implicitly clear that two woofs can be just as good as one. The two thumbnails with crossover schema and costed crossover/ speakers for a 'balanced' 3 way design make a powerful point about what can be achieved cost wise and sound wise when you have the know how and are not dependent on 'key in hand' solutions such as the now closed designs by TG.
Maybe I can find a friend who could help me interpret and convert it into a parts list/ actual,physical design.

In spite of your best and incredibly generous efforts, I'm in well over my head with the ball park baffle/room response graphs. I've looked hard, but I'm afraid I really don't know how to interpret and extrapolate from them. Maybe, you, or andy19191, could summarise their implications in layman's terms - especially good of you to include a graph for the Ekta 11... I hear a deep sigh from out there, somewhere ...

PS re the thumbnails in post 11, I understood these to be a general picture about the effect of different baffle designs. The DIY picture was Tony Gee's Soup Ceramique 11 and crossover design - apparently not available now, but in any case I think those Acuton drivers are pretty pricey items. Interestingly, Tony Gee appears to be the brains behind Humble Hi-fi. He seems to be leaning in the less is more aka es22/es14 direction that Robin Marshall/ Epos acoustics, Naim and others espoused some 30 years ago. I don't suppose there's a debate to be had about this now... I recall at least one raised eyebrow on this forum when Tony Gee's 'Plutone' 2 way came under review. What is it about these guys with TG as their initials?
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Old 14th November 2017, 03:31 PM   #33
PJN is offline PJN  United States
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Hi Paul,

This is an example of a sloped baffle for time alignment, in this case due to driver placement the slope is about 8 degrees from vertical to give good alignment at the listening position. This is also taken into consideration in the crossover design. The woofer position was determined by in room measurements that gave the smoothest response in the room these were intended for, then the mid/tweet were mounted as close as possible. The slope was determined by doing the math from the design listening distance (~ 16-18 ft) to the acoustic centers of the drivers. Simple trig, built a spreadsheet model and adjusted the angle to yield the minimum difference between the distances between the acoustic centers and the design listening spot. The wider baffle for the tweeter and mid did seem to give things a more spacious feeling compared to narrow baffles that I've heard/built. Later I fitted the baffle area around the tweet/mid with felt with the idea to reduce diffraction. I'm not sure if it did much, but it made me feel better. No sub needed. If you can build your own cabinets you have a lot of freedom with design.

Paul
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File Type: jpg 3 way.jpg (206.3 KB, 66 views)
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Old 14th November 2017, 04:40 PM   #34
lupo 1 is offline lupo 1  Italy
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Default PJN's room based design

Hi Paul,

Wow, beautiful speakers and certainly what I would aspire to for a 3 way design as far as looks are concerned! Your comments provoke some key questions for me that seem to me to be in lockstep with this thread.

I'm assuming that the in room measurement work was done with a room simulator program of the kind that andy19191 refers to in post 30?

How much freedom to design own cabinet? I get it that room measurements come first, but then what about issues re volume, the nature of each driver's enclosure, the positioning of bracing and of vent where appropriate. Who or what determines these? Was Rick Craig involved in this aspect of the design, or just in the specification of the crossovers and speakers once you had decided on the cabinet's form? Which is the very first step with those cabinets e.g. an informed guess at dimensions with pure aesthetics as the initial guide?

A lot of quite naive questions I know, but I would love to have just a simple outline idea of the sequence of your project and what it entailed.

I'm particularly interested in your comment about no need for a sub. TG has said this about some of his designs but as far as I can see, he never explained why!

All the best and thanks for this intriguing post,

Paul
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Old 14th November 2017, 05:54 PM   #35
PJN is offline PJN  United States
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Hi Paul,

The first step is setting your goal, mine was a 3 way floor stander with adequate bass response that would fit my room decor. Next step is driver selection, best bang for what you can afford, at the time I liked some of the offerings by Peerless and chose them. Once the drivers have been selected you run some box simulations to get an idea of the cabinet dimensions. In this case I had been speaking with Rick ahead of time about my project and about doing the crossovers for me. Rick had worked with this model woofer before and recommended a sealed alignment so that is what I modeled it for. I could have went with a ported design also, but with room gain and a recommendation I went with sealed. Once the cabinet dimensions are understood, move on to the styling piece that can fit with the constraints of the cabinets size and room. I had an idea of the volumes to make the drivers happy, I used a spl meter and a test CD to get in room responses for the woofer placement relative to the floor. I found that the placement above the floor did affect response (floor bounce, ect) so I settled on a height that gave me the smoothest in room response up to ~ 500 hz, after that I didn't much care since the woofer would be rolled off in the crossover. Once the woofer height was set I finalized the cabinet design and styling. Then I sent the drivers to Rick with a copy of my intended cabinet design. He has much better measuring tools and experience than me, and did far field as well as near field measurements of the drivers mounted on a baffle. He then completed the crossover design and returned my drivers. After which I built the cabinets and crossovers and assembled things. As for the subwoofer thing, some people love big powerful bass, it might not be natural, but who are we to tell them what to like. I listen to a lot of live music and like a natural, realistic response, the lower registers on a base should sound close to what you hear at the concert, not liquefy your bowels. Because of room gain a speaker can give better base response that a simple box model predicts. There are some free excel based models that will allow you to model room gain to get a feel for it. So in my room (14' X 28' x 8') with 10" woofers I feel get more than adequate base with response down into the high 20's. If you go with a pre-engineered kit the designer has already went through all of these steps for you, so you just buy the kit and build the cabinets according to the supplied plan. By the way, building the cabinets is the hardest part, and can get pricey, but it is satisfying when you're done.

Paul
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Old 14th November 2017, 06:19 PM   #36
lupo 1 is offline lupo 1  Italy
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Hi Paul,

This is very clear and helpful and interesting - plenty for me to explore over the next day or so, Meanwhile:

So the test measurements were done with just the bare woofer hooked up? Which test CD?

I can see that the use of a single 10/12" driver might have an advantage over 2 woofers
in terms of height from floor - something that concerned me about Rick's "Essenza".

I'm with you on bass and bowels and being close to the original event, be that concert hall or studio!

Great post which converges very nicely with LineSource and andy19191 comments.

Paul
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Old 14th November 2017, 08:06 PM   #37
PJN is offline PJN  United States
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Hi Paul,

I used the just 10" woofer in a sealed box, close to the volume of the final design. good enough to get a feel for in room response for the bass area. I didn't care about anything else because the actual response of the drivers and the final response would be measured and taken care of in the crossover design phase. The test CD was just frequency sweeps, 20 HZ, 30 Hz, 40 HZ .....500 HZ.

Two woofers can have the advantage over one woofer in some designs, for example two 8" woofers have a displacement greater than one 10" (450 cm2 vs 345 cm2) and can provide lower distortion (higher SD don't need to move as much), might be able to cross higher if needed for the midrange choice, and have higher efficiency depending on the design. Two 8" woofers can give just as low bass as bigger woofers, and there are a lot of nice 8" woofers available on the market. They can also provide a slimmer cabinet which is a look that a lot of people like. Of course the downside is that you need to buy two more woofers, but in the grand scheme of things that's not a big deal. If you have any questions/concerns about a designers choices you ought to be able to contact them for clarification. In Rick's case he has a blog/forum on his website, he knows better than me about the trade offs between many vs single woofers.

Paul
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Old 14th November 2017, 09:11 PM   #38
lupo 1 is offline lupo 1  Italy
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Again, really helpful, thank you Paul - got to contact him then!
Paul
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Old 15th November 2017, 01:30 PM   #39
andy19191 is offline andy19191  Europe
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Quote:
Originally Posted by lupo 1 View Post
the other reason was a comment by someone, way back in time, to the effect that he worried his es22's transient response might be too good for a sub to keep up with ...(?) ... (!)
Did he also talk about "fast bass"? What you hear at low frequencies is mainly the room resonances and these tend to build up loud and resonate for a long time. The brain can separate source and room by processing direct and indirect sound differently but this tends to happen for frequencies above those handled by subwoofers.

The lowest frequencies the ES22 can produce will be boosted by the box/port resonance but at these frequencies a typical subwoofer will not be boosting its output with its own box/port resonance which will be at a lower frequency. This means that over the frequency range the ES22 and the sub overlap, the sub cone will follow the input signal better than the ES22.

Quote:
Originally Posted by lupo 1 View Post
So thanks for gently nudging me forward. Not too clever at interpreting graphs, as I'm sure you've figured already, but I take it that thumbnail 1 = bad and thumbnail 2 = good
There is more to it than that. The plot illustrates how a sub can absorb axial room resonances but there are other considerations. If you cancel a lot of sound to get an even response then that even response is going to be quiet. So you need a lot of cone area so that the sound that isn't cancelled is loud enough. It also uses symmetry to cancel some of the modes but real rooms are often not symmetric requiring subwoofers in more than one place. So in the real world good implementation tend to use perhaps 4 subwoofers and some DSP so that the subs can act differently at different frequencies.

Struggling to interpret graphs will cripple your ability to gather evidence and lead you to being blown this way and that by marketing and nonsense.

Quote:
Originally Posted by lupo 1 View Post
If, as you suggest (and I've heard it said before), a sub is better thought of as a means for controlling room response, can a sub do this AND act as substitute for a 10/12" single woofer (or 2 x 8" ones), or would it be better to see it as more effective when working alongside balanced 3 way 12/10 - 5/6 - 1 speakers such as the SBA 10?
It doesn't matter much whether the main speakers are satellites or full range if they are adequately sized. A pair of subs close to satellite mains is a bit more flexible but full range mains generally won't short change clean SPL around the crossover region which small bookshelf speakers as mains likely will.
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Old 15th November 2017, 05:04 PM   #40
lupo 1 is offline lupo 1  Italy
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This is very helpful and very clear - thanks!
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