Ah, semi DIY : commercial stuffs in kit... or already made...
25 Hz F3....
That'll just do it...in the kitchen
Back on topic: another nice M2 build from the audioheritage forum:
The builder's comment on the M2 vs his Dynaudio acoustics studiomonitors :
"I already liked the Dynaudio a lot, but the M2 sound much better in many aspects! Strings (violin, cello) sound more realistic and less aggressive. Low frequencies are much cleaner (and deeper) and directivity considerably lower! All in all, a nice improvement."
The builder's comment on the M2 vs his Dynaudio acoustics studiomonitors :
"I already liked the Dynaudio a lot, but the M2 sound much better in many aspects! Strings (violin, cello) sound more realistic and less aggressive. Low frequencies are much cleaner (and deeper) and directivity considerably lower! All in all, a nice improvement."
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If these DIY M2s are really that much better than these Dynaudio monitors then it was definitley worth the effort. They even look drop dead gorgeous - better than the original.
Regarding my house: No room in my house is as large as the "kitchen" shown on the picture posted by Juhazi - apart from the attic which would be even larger than that one. While it would be tempting to change the attic into a darn cool listening room it would also cost a lot. So the room the speakers will be used in will be my listening-room and electronics lab. In my early twenties I used the adjacent room for listening to my actively driven corner horns. Sometimes I annoyed almost the whole of our one-horse town. My music taste was known quite well as far away as 1 km.
I wouldn't listen that loudly anymore nowadays and one of the 15"s would be sufficient from this POV. But I will use some transient-improved crossover topology between woofer and midrange. The double woofer will help in reducing the lobing inheren to such crossovers and will also exite room modes more evenly (hopefully) - and two 15"s look darn cool after all.
The dipoles shown look darn cool as well. The build quality seems to be immaculate let alone the drivers used.
The mentioned 18 sound waveguides would definitely be cool (I am about to finish an MTM with an XT1464) but those are 1.4" while the JBL driver is 1.5". The PT waveguide was one of the easiest 1.5" options to obtain. There is also an 1.5" waveguide by D.A.S but it is of the classic CD type with straight walls. I guess the PT does have less HOMs than such a type of waveguide. And a SEOS would not be that much different from a PT waveguide I guess. Since the topology is a three way, the horn wouldn't need to go as low as it has to in the M2. And the M2 horn wouldn't look that good in my setup. Although it looks very good on the DIY M2 that was posted above.
Regards
Charles
Regarding my house: No room in my house is as large as the "kitchen" shown on the picture posted by Juhazi - apart from the attic which would be even larger than that one. While it would be tempting to change the attic into a darn cool listening room it would also cost a lot. So the room the speakers will be used in will be my listening-room and electronics lab. In my early twenties I used the adjacent room for listening to my actively driven corner horns. Sometimes I annoyed almost the whole of our one-horse town. My music taste was known quite well as far away as 1 km.
I wouldn't listen that loudly anymore nowadays and one of the 15"s would be sufficient from this POV. But I will use some transient-improved crossover topology between woofer and midrange. The double woofer will help in reducing the lobing inheren to such crossovers and will also exite room modes more evenly (hopefully) - and two 15"s look darn cool after all.
The dipoles shown look darn cool as well. The build quality seems to be immaculate let alone the drivers used.
The mentioned 18 sound waveguides would definitely be cool (I am about to finish an MTM with an XT1464) but those are 1.4" while the JBL driver is 1.5". The PT waveguide was one of the easiest 1.5" options to obtain. There is also an 1.5" waveguide by D.A.S but it is of the classic CD type with straight walls. I guess the PT does have less HOMs than such a type of waveguide. And a SEOS would not be that much different from a PT waveguide I guess. Since the topology is a three way, the horn wouldn't need to go as low as it has to in the M2. And the M2 horn wouldn't look that good in my setup. Although it looks very good on the DIY M2 that was posted above.
Regards
Charles
Bullsheet!
"Radiation :
dipole through entire spectrum
front side controlled directivity"
No way possible, that is just marketing hype. Dipole radiation to say 500Hz and perhaps contolled (narrow) dispersion fro 1500Hz up. But what happens between 500 and 1500Hz.... I have an educated guess but this is getting way out of context.
"Radiation :
dipole through entire spectrum
front side controlled directivity"
No way possible, that is just marketing hype. Dipole radiation to say 500Hz and perhaps contolled (narrow) dispersion fro 1500Hz up. But what happens between 500 and 1500Hz.... I have an educated guess but this is getting way out of context.
Well, whatever the radiation pattern, dipole or not dipole, this is a kind of rear firing tweeter.
If i read Linkwitz well, his LX literature left me under the impression that true dipolar pattern is not really the goal for the last top octaves, simply using a trick to send more high freq energy to the room using the rear side of the speaker.
If i read Linkwitz well, his LX literature left me under the impression that true dipolar pattern is not really the goal for the last top octaves, simply using a trick to send more high freq energy to the room using the rear side of the speaker.
Though I like Paul's raptors - mine look a little different. Here is a glimpse on the still raw cabinet with the drivers in place (just for checking the look).
http://www.diyaudio.com/forums/multi-way/237750-2x12-horn-speaker-design-3.html#post4645994
Regards
Charles
Edit: Yes, this is the D.A.S horn I was talking of.
http://www.diyaudio.com/forums/multi-way/237750-2x12-horn-speaker-design-3.html#post4645994
Regards
Charles
Edit: Yes, this is the D.A.S horn I was talking of.
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I am still considering the XT1464 for the 'top cabinets' on my 15" cabs, but would prefer a wider horizontal dispersion. The XR1496 comes to mind, but these are not as 'smooth'.
Will you be using the XT's with 18Sound comp. drivers? These are all metal domes and supposedly very good, but I would prefer polymer or PEI diaphragms for home use.
Will you be using the XT's with 18Sound comp. drivers? These are all metal domes and supposedly very good, but I would prefer polymer or PEI diaphragms for home use.
Seems like an excellent choice!
I seriously consider Faital drivers as well. The tiny 1" drivers appear to deliver the smoothest response imaginable between 3-12000 Hz. I have not yet listenend to Faital comp. drivers, but others have reported amazing sound quality (in terms of transparency, smoothness), surpassing even the best dome tweeters.
Ozone seems to have disappeared but there has been a lot of interest in this. It is one of the most shared and most asked about projects. I decided to put something together that is a super simple DIY project. I am constantly helping OEM customers with designs that may end up selling for $100,000 or more. Doing an ultra cheap design was a new experience but I think it works out well. Plans will be available free. Material cost is very low. That allows money to be put into quality drivers where it is best spent.
There were a few revisions to get to something super cheap. The first version was going to use extruded aluminum tubing from 8020 to make a frame. Then it clicked that one of the benefits of the Dipole and LO woofers is they have a solid pole and phase plug. No vent in back. We can drill and tap the back plate allowing to bolt a rear leg right onto them. No need for a separate frame. This let us bolt the unistrut to the back in the first revision a simple MDF leg in the second even cheaper version.
The LO15 were an easy choice. The goal was for more priority on efficiency over extension. These will get down quite nicely to 32-35hz depending on room placement. The distance from the wall behind can either decrease or reinforce the low end output. Room position is somewhat important in this case. The upper end we tried many things. We tried smaller waveguides and even large SEOS24 waveguides. The main issue is we need something readily available. Supply of the SEOS is never a guarantee so we looked elsewhere.
On paper, the Faital HF146 on the LTH142 horn looks great. The upper end is extended well without much craziness in the impedance curve. We used this in the design with the unistrut and baltic birch plywood. This was a modular design that bolts together and has no fasteners from the front. The issue is that the HF146 has a pretty good dip around 1800hz. On the LTH142 it is about 8dB or so and wide enough that we don't like it. Faital didn't really have any answers for us. We are still discussing this. The other issue is the LTH142 doesn't REALLY extend as low as we would like. By 800hz it is fairly rolled off. It should be a little larger or deeper. This was the same issue with the SEOS15 which is quite small and shallow for a 15" waveguide.
The second revision ended up using the deeper, slightly larger 18sound XT1464 waveguide. This loaded lower bringing the real useable response down to 800hz without problem. It also reduced the dip at 1800hz to something that was reasonable. Now we had something to work with. This one makes the materials VERY cheap. Each baffle is made from a single 2'x4' piece of MDF that can be purchased from home depot. A 4" strip is ripped off and used to make the rear leg. Three holes are cut and drivers are flush mounted. A pair of baffles with rear legs can be made for about $30 with all bolts included. The sample here is just raw MDF. Not painted. No rounded edges. Drivers not flush mounted. People can take that and work with it though. It could be nicely veneered plywood, painted, rounded edges, double or triple up on the baffle, etc.
Now, in regards to the waveguide, it is 60 degrees. This actually matches quite well to the open baffle pattern. While a 15" driver is normally about 90 degrees up to 800hz, in the OB configuration it is really closer to 60 degrees. You get the nulls to the side that eliminates reflections from the walls. The directivity of the waveguide does similar. Yes, there is no rear wave in this case. However, take into account the wavelength. At low frequencies, you may be only 1-2 wavelengths away before the rear wave hits the wall, turns around and comes back. By the time you get to 800hz, you may be 8-10 wavelengths away before the sound reflects back forward. It can add a little to the spaciousness of the sound, but in reality it is not helping with the accuracy of what is intended to be played. For this reason, I prefer the sound of the upper end not being open baffle.
When it comes to compression drivers, the HF146 sounds pretty good. It is the best reasonably priced compression driver I have found. The top most octave is quite good. It isn't as good as a JBL, TAD, or Radian Beryllium, but it is 1/4 the cost. 18Sound did tell me they have a Beryllium compression driver coming soon. It is quite expensive, about $1100 retail, but they assured me it is the best available. I will see when it gets to that. For now, the HF146 on the XT1464 is pretty good and available easily.
The other issue though is that the compression driver needs to be substantially padded down passively. It simply doesn't need to have the efficiency it does. For this reason, I may look at using a beryllium dome on a waveguide soon. SB Acoustics has a Beryllium dome coming out that could be a great solution. Using it with a waveguide to bring up the low end output and lower distortion could be a perfect option. I will know more on this by end of the year.
A final option is the Mundorf AMT164UM2.3-R. This is a NICE AMT. Vertically we don't need much dispersion. This is the cleanest and lowest distortion AMT I have seen. For 800euro it should be though. In comparison, distortion is 25dB or more LOWER than something like the PHT1-6 planar from PE. I am looking into a waveguide that can extend the response just a little more to get under 1KHz. Distortion is already low enough it can get close but we don't want power limits to be the issue.
Anyway, to lead back to the original JBL M2, I have been asked to design a system that a customer can sell to this market. Much of the info on the compression drivers is relevant to that conversation as well. In a head to head, the TD woofers provide lower distortion than the JBL woofers. Getting the CD that can handle the upper end is the key. Again, Radian, 18sound, etc are all in the conversation. Beryllium is really a must. The design will be much more unique looking as well. A DIY kit plan will be available as a very simple, square corner cabinet design as well. Again, it is something that the DIY user can be confident will work. Then they can work on the aesthetics to their own liking.
Attachments
I haven't listened to them either so far. But from the 1" Faitals that I also have I once made an informal measurement "out of the box" on an 18s XT1086 horn. Here you can see how it measured:
http://www.diyaudio.com/forums/mult...ifi-speakers-eighteensound-4.html#post4607060
I would say +- 2dB from 1 kHz up to 15 kHz without any EQing isn't that bad ! Is it ?
Yes, the woofers are 15LX60v2. Usually people thake the SM115 for things like that because its response is quite flat and extended. But the LX seems to have lower hd and it can also be tuned a little lower due to the higher Qts.
Regards
Charles
not so easy to matc a raw 8" to a horn... this 8" should be a little horned also ? that's why i ask to Pano if in the history of VOTT some had trie to scale down the enclosure to use it with liitlier driver a little front loaded à la vott, tannoy, etc ! or going with a 4" horned maybe à la Avantgarde with a rcf phase plug plastic horn for 8" ?
matching off axis polar patern with horn & driver need specialists
matching off axis polar patern with horn & driver need specialists
Eldam, you're right. I confused the XT1086 with its smaller brother, the XT120.
The XT1086 is better suited to 10" or 12" woofers, whereas the XT-120 would be appropriate for mating to an 8".
Alignment won't be a big issue, though. The woofer could be be rear mounted with an round over to the baffle.
The XT1086 is better suited to 10" or 12" woofers, whereas the XT-120 would be appropriate for mating to an 8".
Alignment won't be a big issue, though. The woofer could be be rear mounted with an round over to the baffle.
I'm very curious about the sound of this compression driver ! Idem for the Peerless compression driver Bawslo member is talking about in is new little Synergy design thread !
Although I have no sufisant area free to construct one yet I'm a believer of these new design, especialy when it comes to horn a little Sd classic driver like some do (xrk971, etc). The arrays are expensive for my walett (Wesayso very good design: Thre Tolkien two towers as I call it : they should sound demoniac )
So ho to have a little efficienty with not too much driver and amp... synergys, horns, etc...
What do you think then no sufusant free aera to have a straight horn for the mid (Volvotreter, etc...) to load a little a 8" with such stuff and have maybe a load à la VOTT behind : H6000, RCF ? : with a Faital or the B&C highly rated elsewhere by some members : 8PE21 ?
Efficienty, low cone mvt could reduce distorsion while matching the subjectiv fastness of such compression drivers we are talking in this thread ?! Many say it is good despite the high slope of a BR is not the mosdt easy to integrate in a room (we prefer most of the time the slower slope in the end of sealed design... maybe also for the tempo- but is it not due also of the missing BL of hifi drivers in sealed arrengemenent ? I don't know, but asking myself about that !)
When I see all the good designs of members here : many synergies for instance, the most difficult seems always the mid and low end efficienty ! (I'm not worry too much about the mid-high and treble....)
No doubt than the M2 JBL wave guide is a good one reading all the people liking the sound of this monitor : But hard to source here because the price : direct USA import ! Ten times more expensive than a generic horn or same price than a Huchi wood horn replica (90x60°)....
Notice I have a weak understanding of horns world
! But for my next speaker planned for a while now (when I will have the free aera) I want like many : some efficienty and subjective dynamic behavior having yet classical low/medium efficienty speakers !
PS : I'm really sure the OB design has a subjectiv good performance in the mid-bass but what about the lack of efficienty (due to the dB loss at those frequencies despite the active setups and Linkwitz transform ?
I'm sure we are many to be more curious about the sound of the 15" bass reflex of the M2 than the coaxaial CD in its new JBL wave guide !
Although I have no sufisant area free to construct one yet I'm a believer of these new design, especialy when it comes to horn a little Sd classic driver like some do (xrk971, etc). The arrays are expensive for my walett (Wesayso very good design: Thre Tolkien two towers as I call it : they should sound demoniac
)So ho to have a little efficienty with not too much driver and amp... synergys, horns, etc...
What do you think then no sufusant free aera to have a straight horn for the mid (Volvotreter, etc...) to load a little a 8" with such stuff and have maybe a load à la VOTT behind : H6000, RCF ? : with a Faital or the B&C highly rated elsewhere by some members : 8PE21 ?
Efficienty, low cone mvt could reduce distorsion while matching the subjectiv fastness of such compression drivers we are talking in this thread ?! Many say it is good despite the high slope of a BR is not the mosdt easy to integrate in a room (we prefer most of the time the slower slope in the end of sealed design... maybe also for the tempo- but is it not due also of the missing BL of hifi drivers in sealed arrengemenent ? I don't know, but asking myself about that !)
When I see all the good designs of members here : many synergies for instance, the most difficult seems always the mid and low end efficienty ! (I'm not worry too much about the mid-high and treble....)
No doubt than the M2 JBL wave guide is a good one reading all the people liking the sound of this monitor : But hard to source here because the price : direct USA import ! Ten times more expensive than a generic horn or same price than a Huchi wood horn replica (90x60°)....
Notice I have a weak understanding of horns world
! But for my next speaker planned for a while now (when I will have the free aera) I want like many : some efficienty and subjective dynamic behavior having yet classical low/medium efficienty speakers ! PS : I'm really sure the OB design has a subjectiv good performance in the mid-bass but what about the lack of efficienty (due to the dB loss at those frequencies despite the active setups and Linkwitz transform ?
I'm sure we are many to be more curious about the sound of the 15" bass reflex of the M2 than the coaxaial CD in its new JBL wave guide !
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@janovitz: the Faital LTH's are tractrix horns. To get proper loading towards 800Hz these would need more expansion towards a bigger throat, the horns would subsequently become even deeper.
@phase_accurate: this was an interesting concept from a few years back. 15XL60V2's in big BR cabs with CD10Nd's on SEOS-15's. Unfortunately, for whatever reason the guy seems to have suddenly abbandoned the project and his website.
@phase_accurate: this was an interesting concept from a few years back. 15XL60V2's in big BR cabs with CD10Nd's on SEOS-15's. Unfortunately, for whatever reason the guy seems to have suddenly abbandoned the project and his website.
An externally hosted image should be here but it was not working when we last tested it.
@eldam: Iam interested in synergy as well, but I have never heard one.
To keep things simple and expenditure (relatively) low: a big 2 way like the attitube above will easily match the 95dB sensitivity of the M2.
I have some older 15 mid-low's that are towards 100dB or beyond. In a large br cab (or onken/vott) you would need only a few (2a3) watts to get these singing. You would evidentally compromise on state of the art technology like in the M2 (high end waveguide, dsp controlled xo etc.) and therefore end up with response curves etc. which are 'less than stellar'. However, within my budget, these compromises are easy to make.
To keep things simple and expenditure (relatively) low: a big 2 way like the attitube above will easily match the 95dB sensitivity of the M2.
I have some older 15 mid-low's that are towards 100dB or beyond. In a large br cab (or onken/vott) you would need only a few (2a3) watts to get these singing. You would evidentally compromise on state of the art technology like in the M2 (high end waveguide, dsp controlled xo etc.) and therefore end up with response curves etc. which are 'less than stellar'. However, within my budget, these compromises are easy to make.