Open source speaker project?

[Andersonix]

and why not ported woofer ? you don't like ported woofer design in general or just in this case ?
I m curious to know.

About vented boxes, in Linkwitz's own words: "I would say 90% of loudspeakers out there today use this concept to get a little more bass. Because if you put the resonance [of the vent] below the resonance of this driver in the box, and it seems that you get more bass. I find you now have bass ALL the time!"

 

[mordikai]

haha that's the thing, I only read the reviews and good ones on basszilla and havn't heard it myself, so i would appreciate it if you have told me that because it will save a lot of headache later on ! I m not insisting on this if it sucks
so 2 questions tho, why it sucks ? I mean, it has very high sensitivity, flat respond, and the Fostex is a well known driver, so you think the whole setup doesn't fit together or the speaker is not well designed ?
and why not ported woofer ? you don't like ported woofer design in general or just in this case ?
I m curious to know.

I don't want to say too much because my time listening was short and not in my own house. I did get to play my own choice of music though. Bass seemed sloppy, lower mids congested, upper mids shrill, mid falls apart with high volume and complex music. I don't remember anything about the tweeter but I have used that tweeter before and it worked fine. I have heard ported bass that sounded great so I think I just don't like the fostex, at least in this implementation.

 

[Andersonix]

I accept your description of the Basszilla's sound in its entirety, top to bottom, mordikai.

BUT, open baffle top end along with a sealed bass box since the mid 90's remains today as 'the grand compromise': the compromise of a perfect 3-way dipole (Orion) to allow a sealed woofer instead, for reasons of cost and width.

 

[mordikai]

Thank you.
I have owned Orions and am working on a set of LX521's so I have no problem with open baffle. I also have no problem with the compromise of a sealed bass driver. I do generally prefer sealed bass but have heard excellent ported ones also.

 

[Aatto]

About vented boxes, in Linkwitz's own words: "I would say 90% of loudspeakers out there today use this concept to get a little more bass. Because if you put the resonance [of the vent] below the resonance of this driver in the box, and it seems that you get more bass. I find you now have bass ALL the time!"

I understand what you mean, ported speakers can sound "boomy" and I hate that, it will sound very messy in complex bottom heavy musics, I have the same feeling about TL designs, but at the same time it is a compromise, going with a sealed box require large woofers and large boxes to go that low, which is not always convenient, I would like to try a sealed woofer and trick it to go abit lower with some DSP EQ, haven't heard any so can't comment on that.

I don't want to say too much because my time listening was short and not in my own house. I did get to play my own choice of music though. Bass seemed sloppy, lower mids congested, upper mids shrill, mid falls apart with high volume and complex music. I don't remember anything about the tweeter but I have used that tweeter before and it worked fine. I have heard ported bass that sounded great so I think I just don't like the fostex, at least in this implementation.

o wow thanks for the comment, haven't heard it myself and I couldn't imagine it sounds that bad with those expensive drivers

 

[Aatto]

Here are few more thoughts on the Monkey Coffin. Comments please!

POINTS OF DEPARTURE (as I see them):

• The poll says it should be a three way, and it's okay to cost more than $500 per box.
• There were a few mentions that the speaker should work fine with "weak amplifiers" (AmpCampAmp, small tube amps).
• The speaker should be straight forward to make for DIY novices (we don't want to scare them, we want them to run to the hardware shop and build stuff on their kitchen table). There is no point in designing for expert builders, because they will design their own speakers anyway.
• Quite a few members seem to drool over the Yamaha NS-5000 type of speaker ("monkey coffin" / studio monitor).

MY IMPLEMENTATION IDEAS (to illustrate my proposal, no firm decisions):

• Make a simple rectangular "monkey coffin" / monitor style box, good old three way. Shoud be easy enough to make on a kitchen table. Dimensions roughly 30 x 65 x 30 cm or so (will depend on the requirements of the drivers and box tuning).
• For "weak amp compatibility" I set the efficiency target to 92 dB/2.83V/1m, with bass extension to 50 Hz (-3 dB). Achieving this will not be very easy.
• The impedance curve should be flatish and qualify as "8 Ohm". This means we can't "cheat" with the efficiency target by using low-impedance drivers.
• Use high-quality drivers/parts with the right tech specs for the task. The look of the drivers has to be "right" for a HiFi system in a home environment, but is second priority after the tech specs (people may not want to build a speaker that does not look "right").
• Woofer: 10" looks like the right compromise between size and efficiency to me. I modelled the Fane Sovereign Pro 10-300SC in a bass reflex box (28 litres) and got an SPL of almost 96 dB (2.83V/1m) into half space extending to lower than 50 Hz (-3dB) (see attached plot). That's 90 dB in full space, and with a bit of help of the floor and walls, 92 dB is not unreasonable. Other woofers might work well, too. I am also looking at Volt woofers, but I am really open to suggestions.
• Midrange: Needs to keep up with the SPL requirements, so many of the conventional "HiFi" midranges are out. From the top of my head, I can think of the Supravox 135 LB (advertised as a "full range", but...), Accuton C168-6-990 (maybe a bit too large and expensive!), or the Volt VM752 dome (not a cone as I said earlier, but VERY good, and expensive). Or a Veravox 5S? I am open to suggestions!
• Tweeter: I have not thought about tweeter choices much and I guess there should be quite a few units that would work well. I am a big fan of the Scan Speak D3004/6640 beryllium dome, but that does not qualify here because it's a 4 Ohm unit. The SB Acoustics Satori TW29BN beryllium might be an alternative, although it's also a 4 Ohm unit. The TW29BN is at about 97 dB (> 3 kHz), so it might work out to the 8 Ohm spec with an attenuation resistor in series. I am open to suggestions!
• Cross over frequencies: that will depend quite a bit on the driver choices. However, if possible, I like to set the woofer/midrange x-over frequency such that it fits the baffle-step centre frequency. This makes it easier to compensate the baffle step by fiddling with the woofer SPL vs midrange SPL.
• I have not considered any cost limits for now. The poll results do not seem to indicate any upper price limit. This is something that needs to be defined along the way, and will determine the choice of the drivers and other parts.

Very nice detailed explanations about your suggested project, you got my interest instead of my own suggestion !, I like the idea of classic easy to build look, I like the old school ones better anyways.
I like the Volt driver, expensive but I read good things, not sure if there are easily available here in U.S, or are they ?

 

[Aatto]

1- Post #221 by Zvu - 3-Way standmount, 2x 8-10" Woofers on Sides, 5" Midrange, waveguide loaded tweeter.
2- Post #262 by Andersonix - OB5 - 2x Woofers in sealed box + WTW (MTM ?) open baffle, more info HERE.
3- Post#281 by Lojzek - Yamaha NS-5000
4- Post #294 by LineSource - 3-Way SB Acoustic Drivers 12"Woofer + 6.5"Midrange and 1" Dome Tweeter.
5- Post #296 by wesayso - 3 or 4-Way - Narrow bandwidth with DSP.
6- Post #303 by Andersonix - Alon Model I
7- Post #306 by LineSource - 12" DSP Controlled woofer, 12" midrange, Peerless CD+Wave Guide.
8- Post #310 #335 by Pida - 3-Way 90-91db, 2x8" Woofers, 6-7"midrange and waveguide loaded tweeter.
9- Post #319 #356 by mbrennwa - Monkey Coffin 3-Way monitor ~92db, 10" Woofer, Cone Midrange, 1" Dome Tweeter.
10- Post #320 by Lojzek - Dynaudio Evidence Master, 92db, 4x 8" Woofer, 2x 6" Midrange, 2x 1" Tweeter.
11- Post #320 by Lojzek - Wharfedale Heritage Airedale - 90db, 15" Woofer, 8" Bass/Mid, 3" Midrange, 1" Tweeter, 1" Super Tweeter (subject to alterations in our favour).
12- Post#325 by Yoke - Kii THREE
13- Post#325 by Yoke - Kairos.
14- Post#328 by KaffiMann - 3-Way Scan Speak - 2x 10" Woofer, 5.5" Midrange and 1" Tweeter.
15- Post #336 by Aatto - 3-Way, Basszilla inspired - Deep Powerful bass, 90+db, 12" Woofer, 6" Midrange and 1" Tweeter, DSP+Passive XO.
16- Post #338 by Aatto - 3-Way, Basszilla inspired - Poorman version - Powerful bass, ~88db, 8-10" Woofer, 6" Midrange and 1" Tweeter, DSP+Passive XO.
17- Post #340 by Lojzek - Harbeth Monitor 40.2 - Classic 3-Way, 12" Woofer - 8" Midrange - 1" Dome Tweeter - 35-20KHz +/-3db - 86db.
18- Post #358 by 00940 - Silent Runner - More Info HERE (in German)

 

[Draki]

Maybe this is a belated suggestion, but I decided to post nonetheless. A single 10" in a nice narrow/high aspect enclosure, sealed bass (Discovery 26W4534) which is a very good driver suited to CB, then dedicated 5" mid (Disovery 15M4624). I might substitute the tweeter with SB 26ADC metal dome - just a gut feeling.
In general, I think the Discoveries are excellent performers for a fair price. The SB also.

Link: Lautsprecher Scan Disc

 

[kapelli]

I think that PP midrange is a key to success. Therefore I would go in the route like:
Satori Tweeter (Berrylium or to cust costs soft some) + Morel Rohacell Midrange 6inch. This should give an ultimate mid and top range.

And now for lower end three version:
1. Satori WO24
2. Aluminium Wavecore
3. SS Revelators

All in b-r enclosure, even though I am not a fan of it, however, I assumethatmthis project has also to look reasonable in average house so 2 9-10 nich woofers is probably best solution.

I would never skip the Morel or other hi-end midrange for paper though.

Passive crossover, as flat as possible response, bass rather fast than deep and slow, I think -3dB point should be between 30-35 Hz.

 

[andy19191]

Is anyone apart from myself interested in a group design of a $1k tower along the lines posted earlier? If a couple of people are can they post saying so and we can start a separate thread. If not, it might be useful to keep a list of ideas like this that have been floated and not gained sufficient support to help focus the discussion on the type/s of speaker that might.

 

[mordikai]

Is anyone apart from myself interested in a group design of a $1k tower along the lines posted earlier? If a couple of people are can they post saying so and we can start a separate thread. If not, it might be useful to keep a list of ideas like this that have been floated and not gained sufficient support to help focus the discussion on the type/s of speaker that might.

I'm interested.

 

[Aatto]

1- Post #221 by Zvu - 3-Way standmount, 2x 8-10" Woofers on Sides, 5" Midrange, waveguide loaded tweeter.
2- Post #262 by Andersonix - OB5 - 2x Woofers in sealed box + WTW (MTM ?) open baffle, more info HERE.
3- Post#281 by Lojzek - Yamaha NS-5000
4- Post #294 by LineSource - 3-Way SB Acoustic Drivers 12"Woofer + 6.5"Midrange and 1" Dome Tweeter.
5- Post #296 by wesayso - 3 or 4-Way - Narrow bandwidth with DSP.
6- Post #303 by Andersonix - Alon Model I
7- Post #306 by LineSource - 12" DSP Controlled woofer, 12" midrange, Peerless CD+Wave Guide.
8- Post #310 #335 by Pida - 3-Way 90-91db, 2x8" Woofers, 6-7"midrange and waveguide loaded tweeter.
9- Post #319 #356 by mbrennwa - Monkey Coffin 3-Way monitor ~92db, 10" Woofer, Cone Midrange, 1" Dome Tweeter.
10- Post #320 by Lojzek - Dynaudio Evidence Master, 92db, 4x 8" Woofer, 2x 6" Midrange, 2x 1" Tweeter.
11- Post #320 by Lojzek - Wharfedale Heritage Airedale - 90db, 15" Woofer, 8" Bass/Mid, 3" Midrange, 1" Tweeter, 1" Super Tweeter (subject to alterations in our favour).
12- Post#325 by Yoke - Kii THREE
13- Post#325 by Yoke - Kairos.
14- Post#328 by KaffiMann - 3-Way Scan Speak - 2x 10" Woofer, 5.5" Midrange and 1" Tweeter.
15- Post #336 by Aatto - 3-Way, Basszilla inspired - Deep Powerful bass, 90+db, 12" Woofer, 6" Midrange and 1" Tweeter, DSP+Passive XO.
16- Post #338 by Aatto - 3-Way, Basszilla inspired - Poorman version - Powerful bass, ~88db, 8-10" Woofer, 6" Midrange and 1" Tweeter, DSP+Passive XO.
17- Post #340 by Lojzek - Harbeth Monitor 40.2 - Classic 3-Way, 12" Woofer - 8" Midrange - 1" Dome Tweeter - 35-20KHz +/-3db - 86db.
18- Post #358 by 00940 - Silent Runner - More Info HERE (in German)
19- Post #346 #354 by andy19191 - 3-Way Tower, 2x8" Woofers, 4-5" Midrange, 1" Tweeter.
20- Post #368 by Draki - Tall narrow enclosure w woofer on the side - 10" Woofer, 5" Midrange and Metal Dome Tweeter, More info HERE
21- Post #369 by kapelli - 3-Way High end, ultimate mid and fast bass, -3db 30-35Hz.

 

[Aatto]

Is anyone apart from myself interested in a group design of a $1k tower along the lines posted earlier? If a couple of people are can they post saying so and we can start a separate thread. If not, it might be useful to keep a list of ideas like this that have been floated and not gained sufficient support to help focus the discussion on the type/s of speaker that might.

Andy, can you please provide more info/goals on your suggestion I m pretty sure more people would be interested if they have more info on this.

 

[andy19191]

Andy, can you please provide more info/goals on your suggestion I m pretty sure more people would be interested if they have more info on this.

I would judge there is enough for people to see if this is the sort of thing they want to help develop. My interest is in a group project and the more one person hammers away at the details the less there is for others to build a stake in the project. I also don't want to commit time to something that isn't going to fly.

Personally I would like to contribute a bit to the documentation of the reasoning behind the design, possibly analyse cabinet vibration, possibly analyse sound radiation, currently thinking about practical ways of manufacturing a shallow waveguide (but this also overlaps other interests) although picking a tweeter with waveguide is perhaps the most likely option. Others will be required for the passive crossover design, assessing alternative drivers, cabinet design, a range of documentation,...

Good examples of the type of speaker are things like this and this. This also helps make the case to include a shallow waveguide. Others can perhaps add other commercial examples because it is probably the most common configuration for a "proper" home high fidelity design. Curiously there are relatively few reasonably well documented DIY designs that are straight implementations of good practice without introducing some distinguishing quirkiness like spraying the front wall with the rear radiation from the midrange driver,...

 

[andy19191]

I'm interested.

That's two. I think we possibly need at least one more for a group?

 

[mbrennwa]

I think that PP midrange is a key to success. Therefore I would go in the route like:
... Morel Rohacell Midrange 6inch ... Aluminium Wavecore ... Revelators

...

I would never skip the Morel or other hi-end midrange for paper though.

This confuses me. If you think that PP (polypropylene) is key to success, why do you suggest a bunch of drivers that are not PP?

Also, WHY do you think that PP is important, and WHY are those drivers suited to the task? Or, put in another way: what is the design goal you had in mind when you suggested these drivers, and how do these drivers suit this goal?


On a more general note: after reading Aattos summary list of project/design descriptions I wondered if are we aiming to develop a (somewhat) new speaker design, or are we "just" going to copy / clone existing speakers?

 

[Lojzek]

... I wondered if are we aiming to develop a (somewhat) new speaker design, or are we "just" going to copy / clone existing speakers?

It appears to me that offering both of these approaches and/or a combination of the two would serve the purpose better. The poll should clear further things up.

 

[mbrennwa]

Very nice detailed explanations about your suggested project, you got my interest instead of my own suggestion !, I like the idea of classic easy to build look, I like the old school ones better anyways.

Ok, great!

I like the Volt driver, expensive but I read good things, not sure if there are easily available here in U.S, or are they ?

Volt have a list of distributors. There's none in the US, so I guess one would have to buy from an international seller. I do that all the time with kinds of things, since many companies don't have Swiss distributors. No big deal. Even if there are local distributors, it is sometimes still cheaper to buy internationally.

 

[Paul Vancluysen]

SumanDachepalli

Volt have a list of distributors. There's none in the US, so I guess one would have to buy from an international seller. I do that all the time with kinds of things, since many companies don't have Swiss distributors. No big deal. Even if there are local distributors, it is sometimes still cheaper to buy internationally.

The Volt 3 inch dome VM752 is a nice driver to make something interesting with. Also because the Yamaha NS1000 has a 3 inch dome, but a hard one. The Yamaha NS1000 and NS5000 hold my attention already a long time. My friend purchased a second hand NS1000 and I had the opportunity to listen to it. It does have an amazing fine resolution. I like that speaker, it has something that not many speakers can offer. And I think the 3 inch plays an important role in that, probably also because of a good directivity. I think the Yamaha's are difficult to clone 1:1, then you need the same good drivers.

But like Mbrennwa is proposing, a simple but solid cabinet, a high sensititvity (about 94dB @ 1m 2.83Vrms), F3 around 45Hz. And a constant directivity as good as possible (should be investigated in detail).

I see the Volt VM752 costs about 480 euro. Maybe too expensive for this kind of project.

In the past I have looked to midranges w.r.t. constant directivity by comparing their power response versus SPL on axis (driver on infinite baffle ans also in the enclosure). The Accutons have a good behavior. Also the Seas with magnesium cone and the phase plug have a good score. The hard cones with a phase plug seem to be a good match to obtain constant directivity (as good as possible). Doing such kind of invesigation for a new speaker could be interesting.

So I am fan of the simple cabinet, 2 x 8 inch or 1 x 10 - 12 inch woofer, midrange and tweeter to be chosen w.r.t. constant directivity, a tweeter waveguide if needed.

I have no time to built something now, but I will support such design.

Paul

 

[Paul Vancluysen]

But like Mbrennwa is proposing, a simple but solid cabinet, a high sensititvity (about 94dB @ 1m 2.83Vrms), F3 around 45Hz.

Correction on my previous post: the high sensititvity, 94dB full space with 2 x 8 inch or 1 x 10 - 12 inch woofer will be difficult to realize, 90+ is a more realistic target.