Open source speaker project?

[Paul Vancluysen]

Same figure for a closed box. Not much work to post that one also.

If you compare, a closed box speaker with VB = 80 L and F3 = 40 Hz shows a typical sensitivity of 87dB full space. That is 3 dB less than the vented box with the same VB and F3 parameters, see in previous post #500.

Maybe better to say it in another way, a driver with a sensitivity of 93 dB half space in the data sheet, has a F3 = 40 Hz in a cabinet volume of 80 L, sensitivity 87 dB in full space of course.

 

[Lojzek]

Hey fellas, it seems to me that this is getting more and more complicated for no important reason. This is just the stage where we are supposed to find out what people desire the most. You will deal and worry about technicalities later, when a group of designers will have the opportunity to prove their willingness to actually do some good.

 

[Paul Vancluysen]

Lojzek,

Agree, but a minimum of technical study has to be done to avoid that concepts some people are asking for, are impossible to realize. Like a speaker with a F3 of 30Hz in 40 L volume and a sensititvity of 90dB in full space...

 

[Lojzek]

Hi Paul, all the concepts are already done within commercial offerings which should serve and help us move forward without getting stalled. People believe in these, and they will continue to do so if we stick to the rules and continue working on these foundations.

 

[Drummer2005]

I will jump back in with a newbie perspective. If the goal is to get newbies to build it, then I would think that the compromises that seem the most logical, would be to have a straight forward front baffle mounted passive cross full range. There are plenty designs already available that are high sensitivity for the 1 watt guys, and plenty of subwoofer designs. If a newbie wants a high ender that doesn't need to plumb the depths, JB's Kairos are a generally accepted place to go to for the price range, and there exists a sub and passive crossover design available for that too. Most newbies aren't going to be in the tiny watt realm, and there are many reasonable choices for more power. It seems to me that a design such as the Anthologies already clicks off the dual woofer, 3 way full range tower setup. I've yet to see a classic straight forward 3 way, 3 driver setup like the Harbeth, or NS. If you can have good sensitivity/efficiency while not sacrificing extension and range, I think that is a great compromise. Glenn.

 

[Paul Vancluysen]

Kaffimann,

I find your options proposal good. Maybe we can add the F3 value also per option?

The sensitivity in the options are half space values I suppose?

Paul

 

[Paul Vancluysen]

Hi Paul, all the concepts are already done within commercial offerings which should serve and help us move forward without getting stalled. People believe in these, and they will continue to do so if we stick to the rules and continue working on these foundations.

Hi Lojzek

Yes, I understand your point if you see it that way. Some trust in the project is important.
But copy paste is also not that challenging to create something new.
Anyway once the concept is known, we can always look to existing commercial examples.

Paul

 

[Aatto]

I don't get it. Why can such questions not go in a poll? No need to mix them with the other stuff.

mbrennwa, we have 3 choices for design focus(SPL+WAF - WAF+BASS - BASS+SPL), lets say 2 options for largest acceptable volume and 2 options for tower vs classic design. so the combinations will be 3x2x2=12 options, 12 would be the least amount of options if we ignore the price factor, our forum poll options is limited to 10, I still suggest to narrow it down to avoid confusion (less options)

... type and size of enclosure in relation to goal sensitivity automatically dictates low end response, you can not decide that a 60 liter box should have an f3 of 35hz and at the same time achieve 96dbw sensitivity, it is not possible.

I do understand how it works, all I did based on 21 suggested designs and conversations was allowing the bass respond to dictate volume and sensitivity (a different approach) it was just me and I only have one vote

My crude suggestions of what the poll should contain, all volumes are internal volume of enclosure IE not including any material:

Option 01: 88-90dbw 60 liter Classic/Bookshelf
Option 02: 88-90dbw 60 liter Tower/Floorstander

Option 03: 88-90dbw 80 liter Classic/Bookshelf
Option 04: 88-90dbw 80 liter Tower/Floorstander

Option 05: 88-90dbw 100 liter Classic/Bookshelf
Option 06: 88-90dbw 100 liter Tower/Floorstander

Option 07: 92-93dbw 60 liter Classic/Bookshelf
Option 08: 92-93dbw 60 liter Tower/Floorstander

Option 09: 92-93dbw 80 liter Classic/Bookshelf
Option 10: 92-93dbw 80 liter Tower/Floorstander

Option 11: 92-93dbw 100 liter Classic/Bookshelf
Option 12: 92-93dbw 100 liter Tower/Floorstander

Option 13: 95-96dbw 120 liter Classic/Bookshelf
Option 14: 95-96dbw 120 liter Tower/Floorstander

Poll options are limited to 10 (forum rules not mine).

 

[merlin el mago]

Guys that's become eternal....

 

[Lojzek]

Hi Lojzek

Yes, I understand your point if you see it that way. Some trust in the project is important.
But copy paste is also not that challenging to create something new.
Anyway once the concept is known, we can always look to existing commercial examples.

Paul

Paul, this is not about copying, it is about increasing the chances of getting something rolling. The point is not that we take the satisfaction out of it, it's the builders who will get a chance to build something of significant value. What you call a copy is a copy only by appearance. The challenge still remains to accomplish the rest of the design.

 

[Aatto]

I just wanted to say, please keep in mind that this is a team project contributing to the forum
I agree w Lojzek, IMHO we are making this a bit complicated, also we r kinda ignoring the suggested designs we were approaching this in a different way but we have different approaches toward same goal I guess, anyhow if poll is going to determine Sensitivity and Volume as Kaffimann and mbrennwa suggested lets get things going, I suggest to limit the options:

Option 01: >90db - >60 Liter Classic Design.
Option 02: >90db - <60 Liter Classic Design.
Option 03: <90db - >60 Liter Classic Design.
Option 04: <90db - <60 Liter Classic Design.
Option 05: >90db - >60 Liter Tower/Floor standing
Option 06: >90db - <60 Liter Tower/Floor standing
Option 07: <90db - >60 Liter Tower/Floor standing
Option 08: <90db - <60 Liter Tower/Floor standing
With maximum volume of 100 Liter and minimum sensitivity of ~87-88db.


My suggestion is to compromise Sensitivity and let the bass respond dictate the design (IMHO this is might be more revealing, experienced people w sensitive amps know how to build a speaker ):

Option 01: f3>35Hz - >60 Liter Classic Design.
Option 02: f3>35Hz - <60 Liter Classic Design.
Option 03: f3<35Hz - >60 Liter Classic Design.
Option 04: f3<35Hz - <60 Liter Classic Design.
Option 05: f3>35Hz - >60 Liter Tower/Floor standing.
Option 06: f3>35Hz - <60 Liter Tower/Floor standing.
Option 07: f3<35Hz - >60 Liter Tower/Floor standing.
Option 08: f3<35Hz - <60 Liter Tower/Floor standing.
With maximum volume of 100 Liter and minimum sensitivity of ~87-88db and maximum f3 of 40-45Hz.
IMHO this will give wider and cheaper options of drivers.

Edit: And keep in mind that the poll options is limited to 10.

 

[mbrennwa]

people w sensitive amps know how to build a speaker ):

No, not at all! Many novices get into the DIY world via ACAs or similar simple amp kits. Designing a speaker is beyond their expertise. That's why I am so keen on designing an efficient speaker here.

Regarding the poll I'd recommend asking for efficiency, size AND bass extension at the same time (3 options) because not everyone may understand how these go together. Add two more options for classic vs. tower. 5 questions in total, easy.

 

[00940]

The ACA is really an odd one with its 8w. A more typical beginner kit would be a lm3886 or a class d ready made PCB. Quite often 30w/8r - 50w/4r.

And I don't think we should assume the same people are interested in building both amp and speaker. Designing for the average home hifi receiver would make some sense.

 

[Aatto]

No, not at all! Many novices get into the DIY world via ACAs or similar simple amp kits. Designing a speaker is beyond their expertise. That's why I am so keen on designing an efficient speaker here.

Regarding the poll I'd recommend asking for efficiency, size AND bass extension at the same time (3 options) because not everyone may understand how these go together. Add two more options for classic vs. tower. 5 questions in total, easy.

I see your point,
Poll is in radio button style, means that we can only choose one of the already given options it does not work like asking 3 questions you mentioned, we give the options and people can choose one of them or I didn't understand what you meant

it will look like this (of course I will simplify this for better understanding) :

Option 01: >90db - >60 Liter Classic Design F3 of 40-45HZ.
Option 02: >90db - <60 Liter Classic Design F3 of 40-45HZ.
Option 03: <90db - >60 Liter Classic Design F3 of 30-35HZ.
Option 04: <90db - <60 Liter Classic Design F3 of 30-35HZ.
Option 05: >90db - >60 Liter Tower/Floor standing F3 of 40-45HZ.
Option 06: >90db - <60 Liter Tower/Floor standing F3 of 40-45HZ.
Option 07: <90db - >60 Liter Tower/Floor standing F3 of 30-35HZ.
Option 08: <90db - <60 Liter Tower/Floor standing F3 of 30-35HZ.

 

[Aatto]

The ACA is really an odd one with its 8w. A more typical beginner kit would be a lm3886 or a class d ready made PCB. Quite often 30w/8r - 50w/4r.

And I don't think we should assume the same people are interested in building both amp and speaker. Designing for the average home hifi receiver would make some sense.

agreed. but if we can get this off the way w a poll I would say lets do it and get done w it. in the other hand we are going to have another long run to choose driver sizes based on the poll, and then another one to choose the drivers, and ... it would be faster if we went w suggested designs as the set goal, but this is just me, who agrees ?

 

[Luke]

I see your point,
Poll is in radio button style, means that we can only choose one of the already given options it does not work like asking 3 questions you mentioned, we give the options and people can choose one of them or I didn't understand what you meant

it will look like this (of course I will simplify this for better understanding) :

Option 01: >90db - >60 Liter Classic Design F3 of 40-45HZ.
Option 02: >90db - <60 Liter Classic Design F3 of 40-45HZ.
Option 03: <90db - >60 Liter Classic Design F3 of 30-35HZ.
Option 04: <90db - <60 Liter Classic Design F3 of 30-35HZ.
Option 05: >90db - >60 Liter Tower/Floor standing F3 of 40-45HZ.
Option 06: >90db - <60 Liter Tower/Floor standing F3 of 40-45HZ.
Option 07: <90db - >60 Liter Tower/Floor standing F3 of 30-35HZ.
Option 08: <90db - <60 Liter Tower/Floor standing F3 of 30-35HZ.

Perfect, and if you are not sure what 60 litres looks like, go here:

Length, Width & Height to Volume Calculator

I have Kef floor standers which are close to 80L and about 90db from memory. I would not want less efficient speakers than this and the size is OK for my room.

 

[KaffiMann]

I agree.

... Maybe there should be a <150 liter tower 95db(+) f3 35-40hz (or f6 30-35hz) option too?
Could be done with a single 15" for bass.
I have 2 x 128 liters for bass + 80 liters for the rest per channel atm, it's not overly intrusive (when the boss lady got used to it at least), but maybe a bit more than I actually need, definition of huge varies with personal opinion.

 

[mbrennwa]

who agrees ?

There is a gazillion if ways to do the poll. Just go ahead and do what you think is best, it will work out somehow.

 

[andy19191]

There is a gazillion if ways to do the poll. Just go ahead and do what you think is best, it will work out somehow.

Won't it just continue what has gone before? How will the information in a poll provided by anyone that wants to respond to a poll help the small number of people that want to be actively involved in the group design of a speaker (assuming there are any still reading the thread)? Surely a far more sensible way forward is to ask:
- who wants to be actively involved in a group design of a 3 way speaker
- what are they willing to contribute
- what types of designs are they willing to work on

For example, what happens if you run the poll and find in a few weeks time that the most popular configuration is a budget 3 way tower? The chances of this happening are not insignificant but you already know there isn't enough interest in this configuration among those active in this thread and willing to take active part in a group design project.

 

[KaffiMann]

FWIW I would like to help finding suitable parts/drivers and run simulations for what we can expect in terms of bass response (using hornresp), if there is a need for it.

mbrennwa seems like he might be able (and hopefully interested) in helping with crossovers(?), parts and design.

If there is someone adept at realistic simulation of drivers placement on baffle it would be a welcome addition. Possibly waveguide design if there is a need for it, and if we are expecting to have cabinet parts cnc'ed somewhere.

Those are the first steps I guess, then after a while comes building and real life measurements, someone must do that.
Then eventually do a summation of the project and present it.