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Multi-Way Conventional loudspeakers with crossovers

Choosing the right 5" midrange
Choosing the right 5" midrange
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Old 9th September 2019, 11:30 PM   #41
ScottG is offline ScottG  United States
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Originally Posted by MIJK View Post

Instead of adding a 0.5 just use higher sensitivity woofers and lower sensitivity mid, just skip the 0.5 thing and cross the woofers over to the mid at the frequency.



-remember: you've typically got about -5db of baffle-step loss, but you'll effectively gain about +6db from a parallel wiring of two drivers (..amp-output-impedance and current/power-supply capability dependent).

You'll also typically have up to almost +3db of floor gain at lower freq.s. depending on how close a woofer is to the floor relative to any freq..

Plus, you'll often have a bit of baffle-diffractive gain for the midrange.

Finally, depending on the crossover - midrange's are often a "composite" of woofer-mid.-tweet: meaning that if the woofer and tweeter are higher in efficiency and their crossover slope is a lower order design that you typically have a higher eff. result than the midrange alone. (..sort of like the B&O "filler" driver approach.)


No, it's not at all complex..
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Old 10th September 2019, 09:51 AM   #42
andy19191 is offline andy19191  Europe
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Originally Posted by MIJK View Post
I have nothing against a collaboration project if interest in it exists.
It would likely need a significant commitment from you to get the process going and keep it together if it is to be successful. If you are largely neutral then it is unlikely anyone else will pick up the task of driving a group project along.

For myself I would be interested in observing how a group project might evolve compared with others, probably contributing a bit here and there to the mechanical and acoustic design but have no interest in passive crossovers and no interest in building floorstanding speakers for my own use until I move back into a house with a decent sized living room. Others on the forum appear strongly interested in the details of passive crossover design and, given the popularity of the configuration and the use of standard range drivers and parts rather then expensive exotic ones, others are fairly likely to build a well documented and well engineered design.

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Originally Posted by ScottG View Post
-remember: you've typically got about -5db of baffle-step loss, but you'll effectively gain about +6db from a parallel wiring of two drivers (..amp-output-impedance and current/power-supply capability dependent).
MJK is proposing serial 4 ohm woofers not parallel ones and to use an 8 ohm midrange. He also wants/expects the speaker to be reasonably sensitive. Nothing wrong with this as a starting point so long as he then works it through to understand the consequences. It will give him a better understanding of why experienced designers using his 3 way configuration make rather different choices.
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Old 10th September 2019, 12:31 PM   #43
MIJK is offline MIJK  Sweden
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Quote:
Originally Posted by ScottG View Post


-remember: you've typically got about -5db of baffle-step loss, but you'll effectively gain about +6db from a parallel wiring of two drivers (..amp-output-impedance and current/power-supply capability dependent).

You'll also typically have up to almost +3db of floor gain at lower freq.s. depending on how close a woofer is to the floor relative to any freq..

Plus, you'll often have a bit of baffle-diffractive gain for the midrange.

Finally, depending on the crossover - midrange's are often a "composite" of woofer-mid.-tweet: meaning that if the woofer and tweeter are higher in efficiency and their crossover slope is a lower order design that you typically have a higher eff. result than the midrange alone. (..sort of like the B&O "filler" driver approach.)


No, it's not at all complex..
Hmm. I think I need to take one question at a time to not entangle everything in each other.

1. If going 0.5 is out of the question, and baffle width is decided to be 30 cm, what other ways of handling baffle step exists?

2. If more than one way exists, what way has the least amount of negative concequenses?
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Old 10th September 2019, 12:38 PM   #44
MIJK is offline MIJK  Sweden
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Originally Posted by andy19191 View Post
It would likely need a significant commitment from you to get the process going and keep it together if it is to be successful. If you are largely neutral then it is unlikely anyone else will pick up the task of driving a group project along.

For myself I would be interested in observing how a group project might evolve compared with others, probably contributing a bit here and there to the mechanical and acoustic design but have no interest in passive crossovers and no interest in building floorstanding speakers for my own use until I move back into a house with a decent sized living room. Others on the forum appear strongly interested in the details of passive crossover design and, given the popularity of the configuration and the use of standard range drivers and parts rather then expensive exotic ones, others are fairly likely to build a well documented and well engineered design.



MJK is proposing serial 4 ohm woofers not parallel ones and to use an 8 ohm midrange. He also wants/expects the speaker to be reasonably sensitive. Nothing wrong with this as a starting point so long as he then works it through to understand the consequences. It will give him a better understanding of why experienced designers using his 3 way configuration make rather different choices.

3. I'm. Struggling to see what the concequenses would be..
Could you please explain?
What way does experienced designer most often take when it comes to this speaker layout? 8 ogm nominal and high efficiency is what I would like to have, but it isn't decided upon, still possible to change.

It would be nice to have these questions somewhat separate, even if they are in some place connected.

Easier to get a grip on then. For me at least.
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Old 10th September 2019, 01:23 PM   #45
andy19191 is offline andy19191  Europe
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Originally Posted by MIJK View Post
3. I'm. Struggling to see what the concequenses would be..
Could you please explain?
Physics dictates a strict trade-off between size, sensitivity and bass extension often known as Hofmann's Iron Law. If you want the size, sensitivity and bass extension of typical well engineered home audio speakers with 2 x 8" woofers, 5" midrange and 1" tweeter you will have to adopt roughly the same balance of compromises.

By initially concentrating on brands for the midrange you are not in a position to know what your tradeoff and constraints are. This is why an experienced designer would produce a spec first and then iterate it as analysis brings out what can be traded for what and where the sweet spot lies for the intended design.

You have part of a spec: 8 ohms, 2 x 8" woofer, 5" midrange, 1" tweeter, cabinet size, baffle width but some quantities like desired sensitivity, desired bass extension (ported/sealed) still missing. Sitting down with some design software, an initial choice of drivers and working through a simulation will bring out everything that is missing and put you in a position to explore the trade-offs.

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What way does experienced designer most often take when it comes to this speaker layout?
As I mentioned earlier, to answer this look at the good designs with this configuration from the larger home audio manufacturers like Revel, Sony,...
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Old 10th September 2019, 06:11 PM   #46
ScottG is offline ScottG  United States
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Quote:
Originally Posted by andy19191 View Post

MJK is proposing serial 4 ohm woofers not parallel ones and to use an 8 ohm midrange. He also wants/expects the speaker to be reasonably sensitive. Nothing wrong with this as a starting point so long as he then works it through to understand the consequences. It will give him a better understanding of why experienced designers using his 3 way configuration make rather different choices.
Did he propose 2x 4 ohm series? I know he proposed 8 ohm mid..

I recommended the 2x 8 ohms in parallel (and in my statement above: parallel) ..and a 4 ohm midrange with impedance compensation.

So then:

2x 4 ohms in series effectively give no net gain (or loss). (Voltage loss of -3db and acoustic gain of +3db = 0.)
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Old 10th September 2019, 07:49 PM   #47
Zvu is offline Zvu  Serbia
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While we are at it, are there any 8-12 inch woofers that can work well (at least to 45Hz) in a sealed cabinet these days ?
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Old 10th September 2019, 07:53 PM   #48
HorvathS is offline HorvathS  Hungary
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Originally Posted by Zvu View Post
While we are at it, are there any 8-12 inch woofers that can work well (at least to 45Hz) in a sealed cabinet these days ?
Short: no
Longer: what sensitivity? High? The answer is no.
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Old 10th September 2019, 07:56 PM   #49
Zvu is offline Zvu  Serbia
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I know only of Dayton RSS210HF. It behaves very nice in sealed cabinet - goes down to 38Hz in 40 liters. Sensitivity is of no importance as long as i can make it work and not run out of Xmax at 15W.
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Old 10th September 2019, 08:20 PM   #50
Pida is offline Pida  Czech Republic
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While we are at it, are there any 8-12 inch woofers that can work well (at least to 45Hz) in a sealed cabinet these days ?
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