Open source speaker project - Part II

Design Goal

  • Classic -Amp Friendly- Hi Sensitivity (92db+), Higher Bass Ext (f3 40-45Hz), Cabinet Size 60-80

    Votes: 18 17.8%
  • Classic -Bass Friendly- Deep Bass (f3 35-40Hz), Lower Sensitivity (88db+), Cabinet Size 80-110

    Votes: 10 9.9%
  • Classic XL -Amp and Bass Friendly- Hi Sensitivity (92db+), Deep Bass (f3 35-40Hz), Cabinet size 100+

    Votes: 12 11.9%
  • Tower -Amp Friendly- Hi Sensitivity (92db+), Higher Bass Ext (f3 40-45Hz), Cabinet Size 60-80

    Votes: 13 12.9%
  • Tower -Bass Friendly- Deep Bass (f3 35-40Hz), Lower Sensitivity (88db+) , Cabinet Size 80-110

    Votes: 21 20.8%
  • Tower XL -Amp and Bass Friendly- Hi Sensitivity (92db+), Deep Bass (f3 35-40Hz), Cabinet size 100+

    Votes: 27 26.7%

  • Total voters
    101
  • Poll closed .
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However, I have made so many towers that I'd prefer working on a Monkey Box for a change. Who would be interested in joining a design for a "Classic -Amp Friendly- Hi Sensitivity (92db+), Higher Bass Ext (f3 40-45Hz), Cabinet Size 60-80" box?
What does amp friendly mean? For example, are you going to include a high amplifier output impedance in the crossover design? Are you going to select the types of drivers favoured by valve and ACA amp enthusiasts? Is it going to be aggressively budget to match the aggressively budget consumer amps that cannot handle 4 ohm speakers? If it is none of these then what is the point of the high sensitivity and easy load? That is, what type of home audio enthusiast would want a speaker like this enough to build one? Home theatre perhaps?

KaffiMan said:
The big tower build can be maybe a single 15" or 18"?
Then it wouldn't be a tower. Big 3 way tower speakers are deep with a narrow baffle width and, typically, a tweeter at ear height, a pair of midranges above and below the tweeter and 2 or 4 woofers above and below the midranges.
 
... Is it impossible to stick it on the side?

Anyway, equivalent sd of a single 18" is roughly 2 x 12", and 2 x 10" is not very far off a single 15".

I just thought it would be easier to use bigger drivers than trying to find 16ohm units to wire in parallel, and series 4ohm units may not be wise to use in the same chamber, especially for bass. There is a requirement for the design to be 8 ohm.
 
... Is it impossible to stick it on the side?
It depends on the objectives for the speaker which, of course, are not known because they haven't been discussed or defined. Unless the group agrees on what the speaker is to be designed to do then there is no way to determine if a particular option like this is good, bad or indifferent. It needs writing down because what is initially in the heads of members of the group will be different. This is the spec.
 
Andy: AFAIK there is no spec other than: Must be 8 ohm, must be 3 way, must be tower >100 liters, must have as high sensitivity as possible and go flat to 40hz maybe preferably f3 or f6 at around or under 30hz somewhere.

... Maybe we find a suitable 15" to stick in the MonkeyBox? 80 liters max? Might be a stretch. :-D
12" might work, since there's no need for humongous low end.

Edit:
Double 10" or 12" I think needs to be crossed lower than in it was a single 15" or 18", there's something lost when using many large membranes over each other when you go too high. So in my book the xo for a double 10" would be more expensive than that for a single 15", because the components for lower frequencies are more expensive.
 
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So the poll is over.
  • 60% voted for a tower, 40% for a Monkey Box
  • Both camps (tower and monkey box) prefer a high-efficiency speaker
  • The Monkey Box camp prefers a smaller speaker, compromising bass extension
  • The tower camp prefers a big box without compromising bass. The runner up is the bass friendly speaker, with the amp friendly coming in last.

I think it's interesting that the Monkey Box camp has very different preferences than the tower camp (apart from the common trend for high-efficiency).

Now what? The obvious thing would be start designing a "Tower XL -Amp and Bass Friendly- Hi Sensitivity (92db+), Deep Bass (f3 35-40Hz), Cabinet size 100+", because that got the most votes. However, I have made so many towers that I'd prefer working on a Monkey Box for a change. Who would be interested in joining a design for a "Classic -Amp Friendly- Hi Sensitivity (92db+), Higher Bass Ext (f3 40-45Hz), Cabinet Size 60-80" box?

Mbrennwa: Let's start planning for both! High efficiency 60-80 liters sound like maybe a single 10" or maybe 12"?
The big tower build can be maybe a single 15" or 18"?

Slow or fast roll off? My personal preference is slow roll off.

Good idea, we will design both!
From my side I can give my full support for both designs. I have no time to build anything at this moment, I already have a speaker project to do now.
I will think about the concepts also...

Why not ?? :cool:
 
It depends on the objectives for the speaker which, of course, are not known because they haven't been discussed or defined. Unless the group agrees on what the speaker is to be designed to do then there is no way to determine if a particular option like this is good, bad or indifferent. It needs writing down because what is initially in the heads of members of the group will be different. This is the spec.

Not sure what objectives, can you please explain more ?
 
Andy: AFAIK there is no spec other than: Must be 8 ohm, must be 3 way, must be tower >100 liters, must have as high sensitivity as possible and go flat to 40hz maybe preferably f3 or f6 at around or under 30hz somewhere.

... Maybe we find a suitable 15" to stick in the MonkeyBox? 80 liters max? Might be a stretch. :-D
12" might work, since there's no need for humongous low end.

Edit:
Double 10" or 12" I think needs to be crossed lower than in it was a single 15" or 18", there's something lost when using many large membranes over each other when you go too high. So in my book the xo for a double 10" would be more expensive than that for a single 15", because the components for lower frequencies are more expensive.

You know i m in for a monkeybox, but maybe a 15"+ is not exactly tower foot print :D.

this remind me of what LineSource suggest in other thread: Tweek Geek BMF1 speakers - if memory serves me right, this matches what have been voted for. a freakin BEAST :D
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Is this a tower? Floor standing, tweeter at ear level, front mount 15" woofer.
There is a rational for using the large woofer on the front baffle because it usually means the woofer can handle all the baffle step.
ATC SCM150 Active Floorstanding Speakers - Igloo Audio
I actually like this a lot, Troel also has a design like this, the dimensions and foot print and of course the look is between a Classic 3 way and a tower with leaning more toward a classic design tho (Cabinet Dimensions (HxWxD) : 1104x495x635mm).Troel's Fusion looks more like a tower:
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What does amp friendly mean? For example, are you going to include a high amplifier output impedance in the crossover design?

Please see my earlier post where I described my ideas: https://www.diyaudio.com/forums/multi-way/325714-source-speaker-project-36.html#post5526004

To put it short, the idea is a target of 92 dB/2.83V/1m with an "8 Ohm" rating.

Are you going to select the types of drivers favoured by valve and ACA amp enthusiasts?

Given our earlier discussion about cone mass vs. sound I am not sure what you are after here. The idea would be to use efficient drivers to make good use of the limited voltage and current that comes out of small amps. There are numerous novice DIYers building these "weak" amps because they are easy to make, and because they sound good. Yes, these simple amps do not always measure as well as larger, more complex amps, which are harder to make. For instance, my KT66 tube amp (simple enthusiast thingy) does 0.03% THD at 1W and starts clipping at 10W or so, while my Honey Badger (complex super-duper HiFi amp) is better by at least order of degree. However, I cannot say that one amp sounds better than the other, so the measurement numbers may not be as meaningful as some may think. Just let novices (and everyone else) trust their ears when they decide what kind of amps (and speakers) they like.

The general idea that developed early in the Open Source Speaker thread was that the open source speaker should be targeted at such novices because the more experienced DIYers will design their own speakers anyway.
 
..There are numerous novice DIYers building these "weak" amps because they are easy to make, and because they sound good. Yes, these simple amps do not always measure as well as larger, more complex amps, which are harder to make. For instance, my KT66 tube amp (simple enthusiast thingy) does 0.03% THD at 1W and starts clipping at 10W or so, while my Honey Badger (complex super-duper HiFi amp) is better by at least order of degree. However, I cannot say that one amp sounds better than the other, so the measurement numbers may not be as meaningful as some may think. Just let novices (and everyone else) trust their ears when they decide what kind of amps (and speakers) they like.

The general idea that developed early in the Open Source Speaker thread was that the open source speaker should be targeted at such novices because the more experienced DIYers will design their own speakers anyway.
Interesting point here,
you are right, based on what been discussed, goal was to satisfy novice builders, using lower wattage amps. but both polls show other wise, "more advanced builders interesting in something more complex and satisfying from what they have but can't design it them self". just like me.
I mean I can't imaging someone started with ACA or any similar amp, voting to build a beast of a speaker.

So again, pardon my ignorance, but why not designing both ?, one efficient one for novice builder, simple, easy to build and not much expensive, and one with high efficiency and low f3 tower, we can have different threads or continue both here, whichever works.
 
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Interesting point here,
you are right, based on what been discussed, goal was to satisfy novice builders, using lower wattage amps. but both polls show other wise, "more advanced builders interesting in something more complex and satisfying from what they have but can't design it them self". just like me.
I mean I can't imaging someone started with ACA or any similar amp, voting to build a beast of a speaker.

The poll was just about the format and the size/bass/sensitivity compromise. I do not see the "expert vs. novice" aspect at all in the poll. An ACA or other small amp will go very well with a large speaker, if that speaker is "amp friendly".

So again, pardon my ignorance, but why not designing both ?, one efficient one for novice builder, simple, easy to build and not much expensive, and one with high efficiency and low f3 tower, we can have different threads or continue both here, whichever works.

Sure, let's do both! I have absolutely nothing against this. But why do you think that a large speaker with high efficiency and low bass is not for novices? All it takes is to build a bigger box, no big deal :D
 
The poll was just about the format and the size/bass/sensitivity compromise. I do not see the "expert vs. novice" aspect at all in the poll. An ACA or other small amp will go very well with a large speaker, if that speaker is "amp friendly".



Sure, let's do both! I have absolutely nothing against this. But why do you think that a large speaker with high efficiency and low bass is not for novices? All it takes is to build a bigger box, no big deal :D

I just thought of my own experience, I donno how many amps of different types I made through out the years I just recently dared to build a serious(-ish) hifi speaker, I was convinced that passive studio monitors are the way to go! but I built a cheap (less than 300$) WAW (FAST) and it below all the monitors I heard away, and now I m eager for my second one :D But I see your point ;)
 
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ok, so the main factor here is the woofer, I m not sure how one would achieve higher sensitivity than the driver itself like in Zalph SB 12.3, but this is the experts territory, so is that even possible ? if not what are the options ? looks like maybe having one woofer to achieve low f3 and high sensitivity is maybe out of question then, so any ideas ? maybe after figuring how to achieve this we can figure out the driver configurations (if woofer(s) goes on the sides or front).
Or maybe an active woofer ?? :D
 
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Aatto: It can be done with the right driver if it's a 15" or 18", but cost is also important to take into account. Active woofer would be outside the limits of what the poll has decided.

A 15" on the front baffle is probably the lesser evil here, it would ease work with box simulation and xo significantly.
As a side note I think it's a bit unpractical to focus more on f3 than f6, I would rather have a slow roll off than sharp, for numerous reasons, but the limit of 35-40hz should pose no problem.
 
Not sure what objectives, can you please explain more ?
There is a very wide range of speakers designs because people have differing requirements: budget, low frequency extension, SPL, size, shape, looks, high fidelity or high end, etc... A design obviously cannot satisfy all these equally and so for a group project the relative importance of these for a particular design needs to be agreed by all those that are onboard. This can only be done with any reliability by writing it down and getting group agreement. If you don't do this as the design progresses people that have invested significant time and effort will get seriously upset when what they expected the design to be is in conflict with what others that have invested significant time and effort expected the design to be.
 
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