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Old 4th October 2014, 11:03 PM   #1
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Location: Canada
Default Advice for novice speaker builder.

Hello.

I am planning to design (and eventually build) a stereo pair for my small listening area. The layout is such that the speakers will be 7' about, 1.5' feet from the back wall and 10' from the prime listening position. Nine foot ceilings and in one end of a room 25' long.

I am interested in music, mostly classical, small scale with emphasis on voice and the midrange. I wish to have a 3 or 3.5 way speaker system that could cover 9 octaves. My initial thoughts are:

1. the speaker will be a truncated trapezoidal shape with the approximate dimensions 100cm height(before spikes), width 15cm at the top to 30 cm at the bottom. The depth is planned at 30 cm.
2. The primary material will be Appleply plywood by States industries (3/4" or 1".

3. The design will be MTMWW (hopefully) and I wish the crossovers to be housed outside the enclosure.

The initial drivers I have tentative proposed are:

Tweeter: Tang Band 15-1719s (1" ceramic over aluminum dome).
Midrange: Tang Band W3-13645 (paper cone)
MId woofers: Dayton Audio ES180Ti-7 (7" Nomex? cone).

4. The crossovers will be the issue. But I would like to cross over at approximately 600 hz and 4800 hz. The mids would run in paralled as well as the mid-woofers.

5. The woofers I am uncertain about the physical configuration.

a) ported sharing the same enclosure space with twin ports and double are volume.
b) Ported as above but with the .5 technique of crossing the lower woofer at a lower frequency.
c) the top woofer sealed (in its own chamber) and the bottom woofer ported with the .5 as above but of course a smaller chamber than with both. ( I have never heard of this configuration and it just may be silly). Hope springs eternal.

Thank you for any advice or direction and all comments are gladly and gleefully acknowledged.

Artofwar.
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Old 5th October 2014, 06:33 PM   #2
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Location: Maine, Bangor-area
Nine octaves would be 40 Hz - 20 kHz. Not having done any simulation, however my general impression is that your truncated trapezoid with 30 cm sides at the base, and two 7" mid-bass drivers wouldn't be able to produce f3 = 40 Hz.

Quickly looking thru the PE 2013 catalog, I couldn't spot Dayton ES180Ti-7. If you don't have simulation software, and you were to list the specs of that driver, there are probably people here who could tell you what is best to do in the bass range.

Regards,
cT
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Old 5th October 2014, 09:14 PM   #3
sreten is offline sreten  United Kingdom
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Join Date: Nov 2003
Location: Brighton UK
Hi,

Walk before you can run would be a good idea.

$30 tweeter + 2 $20 each midranges is OK but
then you add two 7" bass units at $140 each ...!!

YMMV but I suggest you consider building these :
https://sites.google.com/site/undefi...diy-sunflowers

Click the image to open in full size.

Read the good FAQ's on that the site, and shortcut years of
building speakers, messing it up, and learning the hard way.
https://sites.google.com/site/undefinition/diy-mfaq
https://sites.google.com/site/undefinition/diy-mfaq2
https://sites.google.com/site/undefi...-provendesigns

rgds, sreten.

The esoteric Dayton :
http://www.parts-express.com/dayton-...8-ohm--295-397
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 5th October 2014 at 09:37 PM.
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Old 6th October 2014, 08:39 AM   #4
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Join Date: Feb 2007
Location: Canada
Thank both of you for your replies.
Serena the speaker you showed looked very interesting and I will read up on it.

The cost of the speaker drivers are quite disproportional towards the woofers 4 @ $133 x4=$532. But I did not start there. I started by looking at very competent and expensive midranges like scanspeak and Visaton. It is very difficult to find a good midrange driver which starts in the 150-200 hz range.

I am hoping that the woofer mid x-over @ 500-600 hz would work out although it is in the vocal range. This makes it easier for this small midranges to operate more comfortably and pushes the tweeter x-over into the 4200-4800 hz range.
But this tweeter needs this (apparently).

The Dayton Audio woofers require 1.14 cu. ft. for ported (f3=35) and much less sealed f3=69). This design will provide these volumes.

I only chose to double the woofers for sensitivity, using 8 ohms, 6.5 or 7 inch and neo motors for requirements.
I am prepared to consider other alternatives.
Thank you for your responses!
Artofwar
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Old 6th October 2014, 05:37 PM   #5
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Join Date: Mar 2005
Location: USA
artofwar, welcome to the world of speaker building

This project you have listed here is very ambitious and may become overwhelming quickly. Nailing a 3-way design requires a lot of time, and a lot of measurement. Ultra premium drivers like Scan-Speak and Visaton mids are only good if you already know how to extract the most performance from them. It is also impossible to choose a crossover point without having measured the drivers or having said measurements. The crossover points depend on driver behavior in real application, not the frequency responses provided by manufacturers.

I am of the opinion (very firm opinion) that the best way to begin in loudspeaker design and building is with a verified design. The reason is thus: most people do not have the measurement equipment, money, experience or time required to create a very complex design, much less as a first project. When you start by learning and understanding an existing design, you appreciate the nuances of the hobby but yet know that the net result is going to be excellent.

I suggest that, unless you have already purchased these components, that you look on Tech Talk or Zaph Audio's page for simpler projects. Unlike many things, a poor loudspeaker design is always much worse than the sum of its parts. The converse, however, is also true: it's possible to create the best sound you've yet heard without breaking the bank. If you would like suggestions, I would be more than happy to help you.

The place to start, in my mind, is with the following question: what exactly are you looking to get from a speaker design? Absolute 2 channel fidelity? Home theatre versatility? I think you should consider that first and then go from there. Hopefully this helps some.
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Old 7th October 2014, 03:35 AM   #6
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Join Date: Feb 2007
Location: Canada
Thank you Lemans23.

I think your advice is very sound. My plan is based on the Little Princess mtmww design. I am not in a hurry to rush toward oblivion. I am listening very carefully to what is being said.

I am not a ready, shoot , aim sort of person.
I realize that the final outcome is very room dependent and serious measurements will be required. It is a process of iteration, compromise and competence but not perfection.

To address your question about what I am looking for:
Stereo fidelity yes but I am not sure about absolute. I have listened to many speakers over the years of all types and all have pros and cons. I listen to opera, chamber music, choral works, jazz, blues, folk, etc. the highest priority is the human voice.

The speakers that I liked the best were where the speakers were not driven too hard e.g. Verity speakers, focal Utopias etc. there is a certain effortlessness to this sound.

I would prefer quality over quantity. For example I would rather emphasize phase, low distortions and vocal acuity over high spl, bass extension or extreme resolution.
For example if this system were to be sealed with an f3=69 hz that would be fine with me.

I do not know what spl level to target sitting 9-10 feet from the speakers but it doesn't seem to be too high. There is 3' behind this position and there are 3 seats in a row.

To me it seems this modest 3-way floor stander design will fit in my space and drivers can be recommended that operate in their respective frequency bands and integrate well ( play well together).

I am perhaps not the best at describing this but perhaps this discourse will help.

Again thank you for helping me.
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Old 7th October 2014, 04:02 PM   #7
jReave is offline jReave  Canada
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I see the 2 criteria of MTMWW and quality vs quantity as slightly contradictory.

You can spend x amount of dollars for 2 mids and 2 woofers or you can spend the same amount of money for a higher quality single mid and single woofer. Doubling up drivers is generally for the purpose of increasing the SPL capabilities (ie. quantity), although doubling also means a little less distortion and less effort and thus why I said "slightly contradictory".

Since I don't actually listen to much of the same music that you do I could be wrong here, but I would think that for your tastes you should emphasize the midrange and treble (or at least equivalent quality across all 3 drivers). I'd say your driver selection does the opposite right now.

So start here: how loud do you need to go? --> TMW or TMWW or MTMWW? --> then what does your budget allow for each of the speaker's 3 'ways'? --> pick your midrange 1st and then the T and W to match.

And now contradicting what I've just said above , although there isn't any real feedback on the new ES180's yet, they do appear to be a very high quality driver and you may want to stick with those if your budget allows.
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Old 8th October 2014, 04:20 PM   #8
Jay is offline Jay  Indonesia
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Location: Jakarta
Quote:
Originally Posted by artofwar View Post
4. The crossovers will be the issue. But I would like to cross over at approximately 600 hz and 4800 hz. The mids would run in paralled as well as the mid-woofers.

5. The woofers I am uncertain about the physical configuration.

a) ported sharing the same enclosure space with twin ports and double are volume.
b) Ported as above but with the .5 technique of crossing the lower woofer at a lower frequency.
c) the top woofer sealed (in its own chamber) and the bottom woofer ported with the .5 as above but of course a smaller chamber than with both. ( I have never heard of this configuration and it just may be silly). Hope springs eternal.
Why not use drivers used in a proven design, such that when your crossover design fails miserably (which it will) you can convert to the proven design.

Or you can use the proven design as a benchmark.

It seems that you picked the criteria based on "art", "taste" or "magic". No, it doesn't work like that! There are specific reasons why designers do "this and that".

The crossover frequency (fx) mostly dictated by the chosen drivers. For tweeter fx, it is usually not far from the tweeter's resonance (1.5 to 2x depends on slope steepness). The woofer fx can be 100Hz to 500Hz depends on the woofer-mid match (trial is done during design for each possible fx).

Deciding whether woofers will be series, parallel, same box, or different tuning frequency also done during design based on situations.

Three-way tend to create too low speaker impedance. So you don't parallel 4 ohm woofers but put them in series. Parallel woofers are usually opted to increase efficiency (SPL) to match mid and tweeter.

Parallel mid is usually opted to limit displacement, especially with brittle cone material that tend to break up at high SPL (ceramic, poly-glass, diamond, etc).

Two-and-a-half-way (woofers with different tuning) is rare because it requires that one woofer is efficient enough and the second woofer is only slightly anchoring the bottom end (similar like a port does)
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Old 8th October 2014, 06:12 PM   #9
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Location: USA
Quote:
Originally Posted by artofwar View Post
Thank you Lemans23.

I think your advice is very sound. My plan is based on the Little Princess mtmww design. I am not in a hurry to rush toward oblivion. I am listening very carefully to what is being said.

I am not a ready, shoot , aim sort of person.
I realize that the final outcome is very room dependent and serious measurements will be required. It is a process of iteration, compromise and competence but not perfection.

To address your question about what I am looking for:
Stereo fidelity yes but I am not sure about absolute. I have listened to many speakers over the years of all types and all have pros and cons. I listen to opera, chamber music, choral works, jazz, blues, folk, etc. the highest priority is the human voice.

The speakers that I liked the best were where the speakers were not driven too hard e.g. Verity speakers, focal Utopias etc. there is a certain effortlessness to this sound.

I would prefer quality over quantity. For example I would rather emphasize phase, low distortions and vocal acuity over high spl, bass extension or extreme resolution.
For example if this system were to be sealed with an f3=69 hz that would be fine with me.

I do not know what spl level to target sitting 9-10 feet from the speakers but it doesn't seem to be too high. There is 3' behind this position and there are 3 seats in a row.

To me it seems this modest 3-way floor stander design will fit in my space and drivers can be recommended that operate in their respective frequency bands and integrate well ( play well together).

I am perhaps not the best at describing this but perhaps this discourse will help.

Again thank you for helping me.
A properly executed 2-way speaker will always beat a poorly executed 3 way. When a 3-way is done right, however, the benefits may often be worth the extra driver cost. I do not like half-way designs because as Jay said, the theoretical advantage is outweighed by the practical limitations. We won't get into that however.

The sound you're speaking of is due to low distortion. When drivers are properly integrated, are of high quality, and are able to reproduce their passband comfortably, the power sent to the speaker is turned into glorious sound. When you need to push the speaker to create the sound you want and it cannot handle it, you induce distortion which is likely the strain you mention.

Much like the human body, two components rule all others in loudspeaker design. The brain, #1, is the crossover. You could have Scan-Speak Illuminator woofers and Seas Millenium tweeters, but if you make a poor crossover, the speaker is just an expensive thing to look at. The heart, #2, is the tweeter. People more often than not will spend boatloads on midranges and woofers, and then put a decent tweeter into the mix.

The tweeter reproduces the most crucial frequencies for musical accuracy, that is, the harmonic structure called timbre. If the tweeter creates distortion or is forced to play either too low or too loudly, then your Seas Excel magnesium woofers are worthless also. If the tweeter is not integrated well in the crossover, however, then even a Morel Supreme tweeter is a waste of money.

Now: do not mistake me saying this as advising spending lots of money on a tweeter. Rather, I am saying that if you take some cost from the ultra premium woofer budget and allocate it to a superior tweeter, then you're going to have a nicer sound.

So here is my advice: set yourself a budget for this project such that if it does not turn out the way you want, it will not be considered a complete waste. This could be Dayton Audio classic series woofers and a Vifa DX25 tweeter just to throw out some value options. Design an enclosure for the woofers, and measure the tweeter response IN THE BAFFLE. This is crucial to crossover design. Spend the remaining 80% of your time with a good crossover simulation program (one which accepts real measurements, not X-Over Shop) that lets you easily place components. You will need to match the tweeter level to the woofer level, not the other way around. Knocking down the tweeter level is fine. Running the tweeter flat out with 4 woofers is not.

Buy some x-over components, but don't spend a huge amount. You do not need expensive caps and inductors. Build your first prototype crossover, and listen to it with a reference speaker. Your brain will mask the DIY's flaws because you made it. You expect it to be great, therefore it will be great regardless of its faults. You must have a tried and true reference to combat this. It happens to absolutely everyone who makes their own speaker without anything to compare it to. You may even begin to think that the DIY design is better than "anything in a hi-fi store". Don't fall into this trap.

After you've listened to it extensively, determine what is missing compared to that sound you described. Is there an edge to it? Midrange emphasis? Sloppy bass? Once you get to this point, report back.

Don't forget what I said about the components: expensive components don't promise that the sound will be good. It just means that the components are expensive. Best of luck.
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Old 9th October 2014, 01:46 AM   #10
sreten is offline sreten  United Kingdom
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Join Date: Nov 2003
Location: Brighton UK
Quote:
Originally Posted by artofwar View Post
I am interested in music, mostly classical, small scale with emphasis on voice and the
midrange. I wish to have a 3 or 3.5 way speaker system that could cover 9 octaves.
Artofwar.
Hi,

My suggestion is post #3 is a good as your going to
get, at a reasonable price and well documented.

It is something different in terms of voices and the midrange, and
suits the above outline to a tee, it would be very churlish to ignore.

Note that it is the 3rd generation of a design affected by
years of seriously developing developing speakers, and
you get all that experience for free if you so choose.

Perfect, no, nothing is. Highy developed yes.
No fuss bass tuning recommended.

rgds, sreten.
__________________
There is nothing so practical as a really good theory - Ludwig Boltzmann
When your only tool is a hammer, every problem looks like a nail - Abraham Maslow

Last edited by sreten; 9th October 2014 at 02:07 AM.
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