(posted by Jim Griffin)
You could glue a peice of acoustic foam inside the cabinet to the under side of the top. On other projects I have used heavy acoustic foam that is 50 mm thick. This material has a peel and stick adhesive so it can be mounted on the insides of an enclosure.
Thanks for the tip.
I glued there a 3,5cm thick piece of foam,hopefully it helps to dampen the resonations.
I desided to rebate the driver by hand with a router.
First I covered the surroundings with a tape,made a half millimeter deep circle with scalpel knife,then worked very carefully and slowly with router bit like this /\ .The last millimeter or two was removed with a scalpel knife and sandpaper.
It took about 2 hours to finish both speakers,they even look better this way
You could glue a peice of acoustic foam inside the cabinet to the under side of the top. On other projects I have used heavy acoustic foam that is 50 mm thick. This material has a peel and stick adhesive so it can be mounted on the insides of an enclosure.
Thanks for the tip.
I glued there a 3,5cm thick piece of foam,hopefully it helps to dampen the resonations.
I desided to rebate the driver by hand with a router.
First I covered the surroundings with a tape,made a half millimeter deep circle with scalpel knife,then worked very carefully and slowly with router bit like this /\ .The last millimeter or two was removed with a scalpel knife and sandpaper.
It took about 2 hours to finish both speakers,they even look better this way
Irwan - Thor over on the fullrangedriver.com website uses this approach, albeit without the tweeter. A JX92 down to 100Hz and a sealed sub to take it from there down. In would give greater pwoer handling and, in theory, clean up the midrange on the JX92, although I've not sound this a problem with the MLTL design (below 70Hz or so most of the sound is coming from the port and the driver hardly moves).
Question regard this statement: ...I should add that I strongly suggest that the same baffle width be used for the MLTL as I used for mini-monitor. The crossover network was developed for that specific baffle width so a wider baffle would necessitate a network change...
Previous to this email chain, I build the 48 inch GM MLTL triangle cross section speaker (which are actually 51 inches tall, externally). My external baffle is 10 1/3 inch wide.
Since this is all a grand experiment for me, I have purchased a pair of the GSi tweeters and will install them soon. But, I am still learning about crossovers. What would the crossover for this wider baffle look like? What changes would have to be made?
Thanks for all your help.
Matt
Previous to this email chain, I build the 48 inch GM MLTL triangle cross section speaker (which are actually 51 inches tall, externally). My external baffle is 10 1/3 inch wide.
Since this is all a grand experiment for me, I have purchased a pair of the GSi tweeters and will install them soon. But, I am still learning about crossovers. What would the crossover for this wider baffle look like? What changes would have to be made?
Thanks for all your help.
Matt
Matt,
It is hard for me to tell you with certainity that tweaking the existing crossover network will yield completely acceptable results. The crossover was derived from measurements of the driver in the 7.5" wide enclosure and then optimized in LSPCad. Hence, my recommendation for the maintaining the baffle width at 7.5" as I have a lot of experience and success with that configuration.
Without measurements and a new optimization the specific crossover component values for your new baffle are hard to discern. But I'll try to guide you on one possible direction to go. I would build the network 'as is' for the 7.5" wide baffle. Listen to that configuration and decide if you like how it sounds. If possible, measure the on-axis performance in the 300 to 3000 Hz area where the inherent baffle step comp occurs. Now if you see a more than a couple of dBs hump in the 500 to 1000 Hz range, you could tweak by increasing the value of L1 (1.5 mH) coil to say 1.7 or 1.8 mH for starters. That would reduce that hump without too much impact on the crossover frequency between the woofer and tweeter.
Let us hear how you like the results.
Jim
It is hard for me to tell you with certainity that tweaking the existing crossover network will yield completely acceptable results. The crossover was derived from measurements of the driver in the 7.5" wide enclosure and then optimized in LSPCad. Hence, my recommendation for the maintaining the baffle width at 7.5" as I have a lot of experience and success with that configuration.
Without measurements and a new optimization the specific crossover component values for your new baffle are hard to discern. But I'll try to guide you on one possible direction to go. I would build the network 'as is' for the 7.5" wide baffle. Listen to that configuration and decide if you like how it sounds. If possible, measure the on-axis performance in the 300 to 3000 Hz area where the inherent baffle step comp occurs. Now if you see a more than a couple of dBs hump in the 500 to 1000 Hz range, you could tweak by increasing the value of L1 (1.5 mH) coil to say 1.7 or 1.8 mH for starters. That would reduce that hump without too much impact on the crossover frequency between the woofer and tweeter.
Let us hear how you like the results.
Jim
Fountek vs. Aurum Cantus Driver
I suspect that the Fountek JP3 or NeoCD3.0 can be used to substitute for the Aurum Cantus G2si tweeter. Of course I haven't tried this change so I can not say absolutely that these two drivers are compatible, but specs indicate that they should be close. The Fountek driver is a little less sensitive than the A-C model so you may have to increase the shunt resistor across the tweeter an ohm or two to compensate.
I suspect that the Fountek JP3 or NeoCD3.0 can be used to substitute for the Aurum Cantus G2si tweeter. Of course I haven't tried this change so I can not say absolutely that these two drivers are compatible, but specs indicate that they should be close. The Fountek driver is a little less sensitive than the A-C model so you may have to increase the shunt resistor across the tweeter an ohm or two to compensate.
Jim,
I did some sweaking on the JX92S, some of the experiements are shown here, would like to know what you think.
http://www.diyaudio.com/forums/showthread.php?postid=1227789#post1227789
I did some sweaking on the JX92S, some of the experiements are shown here, would like to know what you think.
http://www.diyaudio.com/forums/showthread.php?postid=1227789#post1227789
soongsc,
The crossover I'm using with the Jordan JX92S is at 3000 Hz so the tweaks that you suggest are not likely to be effective. In general I'm not a tweaker when it comes to the Jordan. My view is that you tweak $10 Radio Shack type drivers but nearly $200 drivers aren't where I want to screw-up.
IN my experience most tweaks are often not reproducible. While I appreciate your measurements, I don't encourage the average Joe without measurement gear to attempt duplication.
My advice is to purchase a better driver if the one that you have isn't floating your boat. Tweaking will not yield a silk purse from a sow's ear.
Jim
The crossover I'm using with the Jordan JX92S is at 3000 Hz so the tweaks that you suggest are not likely to be effective. In general I'm not a tweaker when it comes to the Jordan. My view is that you tweak $10 Radio Shack type drivers but nearly $200 drivers aren't where I want to screw-up.
IN my experience most tweaks are often not reproducible. While I appreciate your measurements, I don't encourage the average Joe without measurement gear to attempt duplication.
My advice is to purchase a better driver if the one that you have isn't floating your boat. Tweaking will not yield a silk purse from a sow's ear.
Jim
Thanks Jim,Jim Griffin said:
Unfortunately I have not come across any off-the-shelf driver that meets my needs. Some metal wide range drivers come close, but still need some teaking due to manufacturing limitations.
Specifically with the Jordans, one can just remove the pattern if it does not work. My post was really a result of multiple iterations on the same driver.
But do you think this elimitates the roughness in the high frequency? I have not listened to the Jordans in properly designed enclosures.
Hi,
This is a bit of topic, but it seems that you guys may have an answer. I have currently been reading various threads and would like to build a speaker based on the JX92S driver. However, I would like to hear some of your experiences. I have recently moved to a small appartment and have a listening room of only 3.5x4 meters, 2.5 up to the ceiling. My current speakers, a 2.5 way seas excel +scanspeak relevator is resonating far to much.
My first question is - which is the better design for a room of my size, the mini monitor with the A-C, the design described in this thread or a "standard" version of the VTL on Jordans web page?
My second question; is it possible to tune the base respons of the MTML design of this thread, and how is this done? I am a total newbee in regards to speaker acoustics, sorry for that.
I will be mating the speaker with my Pass labs Aleph 1.2 clones. Thanks for any help!
Best regards,
Folke
This is a bit of topic, but it seems that you guys may have an answer. I have currently been reading various threads and would like to build a speaker based on the JX92S driver. However, I would like to hear some of your experiences. I have recently moved to a small appartment and have a listening room of only 3.5x4 meters, 2.5 up to the ceiling. My current speakers, a 2.5 way seas excel +scanspeak relevator is resonating far to much.
My first question is - which is the better design for a room of my size, the mini monitor with the A-C, the design described in this thread or a "standard" version of the VTL on Jordans web page?
My second question; is it possible to tune the base respons of the MTML design of this thread, and how is this done? I am a total newbee in regards to speaker acoustics, sorry for that.
I will be mating the speaker with my Pass labs Aleph 1.2 clones. Thanks for any help!
Best regards,
Folke
folkeb said:
Folke,
I have built several enclosures for the JX92S. Tuning the port on any of them makes less audible difference than you would expect.
My listening room is just a little larger than yours and rectangular, the room itself resonates; most loudspeakers either boom or have very little bass. Try running a signal generator into your current system and listening for the room's standing waves, (careful not to overheat the amp.) If they are very pronounced then you will always have resonance, so don't try to get too much bass.
Hope this helps,
Andy
Hi Folke!
I've had the same problems the last three apartments we have been living in. All of them concrete houses!
I had Genelec monitors mated with a sub. The Genelec's have the otion to reduce both bass output and create and sub bass filtering in three steps. These options were not satisfactory due to when no booming, there were no bass at all.
It was not until I started to play with an old Sunfire sub I had lying in a wardrobe. Now this sub is totally useless for music. The drivers are 25 cm driver and a passive radiator.
I simply rip out the passive radiator and put some towel inside the box. Not dipole exactly but some cross breed between OB and aperiodic box. Worked wonder in this configuration, fast natural and tuneful bass in the listening spot. Outside the room no trace of resonances and thereful more NAF (neighbor acceptance factor) Not so deep bass but 30Hz is certainly enough for me with this quality of bass.
Dipole bass is for me the only way to go without bass traps and whatsoever!
Good luck!
I've had the same problems the last three apartments we have been living in. All of them concrete houses!
I had Genelec monitors mated with a sub. The Genelec's have the otion to reduce both bass output and create and sub bass filtering in three steps. These options were not satisfactory due to when no booming, there were no bass at all.
It was not until I started to play with an old Sunfire sub I had lying in a wardrobe. Now this sub is totally useless for music. The drivers are 25 cm driver and a passive radiator.
I simply rip out the passive radiator and put some towel inside the box. Not dipole exactly but some cross breed between OB and aperiodic box. Worked wonder in this configuration, fast natural and tuneful bass in the listening spot. Outside the room no trace of resonances and thereful more NAF (neighbor acceptance factor
) Not so deep bass but 30Hz is certainly enough for me with this quality of bass.Dipole bass is for me the only way to go without bass traps and whatsoever!
Good luck!
Hmm, seems that I'm dyslectict today
Hi Folke!
I've had the same problems the last three apartments we have been living in. All of them concrete houses!
I had Genelec monitors mated with a sub. The Genelec's have the otion to reduce both bass output and also a bass filtering in three steps. These options were not satisfactory due to when no booming, there were no bass at all.
It was not until I started to play with an old Sunfire sub I had laying in a wardrobe that bass improved. Now this sub is totally useless for music, slow is just not enough to describe the sound. The driver is 25 cm with a passive radiator.
I simply ripped out the passive radiator and put some towel inside the box. Not dipole exactly but some cross breed between OB and aperiodic box. Worked wonder in this configuration, fast natural and tuneful bass in the listening spot. Outside the room no trace of resonances and thereful more NAF (neighbor acceptance factor) Not so deep bass but 30Hz is certainly enough for me with this quality of bass.
Dipole bass is for me the only way to go without bass traps and whatsoever!
Hi Folke!
I've had the same problems the last three apartments we have been living in. All of them concrete houses!
I had Genelec monitors mated with a sub. The Genelec's have the otion to reduce both bass output and also a bass filtering in three steps. These options were not satisfactory due to when no booming, there were no bass at all.
It was not until I started to play with an old Sunfire sub I had laying in a wardrobe that bass improved. Now this sub is totally useless for music, slow is just not enough to describe the sound. The driver is 25 cm with a passive radiator.
I simply ripped out the passive radiator and put some towel inside the box. Not dipole exactly but some cross breed between OB and aperiodic box. Worked wonder in this configuration, fast natural and tuneful bass in the listening spot. Outside the room no trace of resonances and thereful more NAF (neighbor acceptance factor) Not so deep bass but 30Hz is certainly enough for me with this quality of bass.
Dipole bass is for me the only way to go without bass traps and whatsoever!
Room Interaction with Jordan JX92S Speakers
With my minimonitor (JX92S with or without the ribbon tweeter) you may have an in-room booming situation within a small room. You can address this issue via either moving the speakers (you change the interaction with the boundary surfaces) so that the boom is mitigated. Another solution is to stuff the port tube with acoustic foam or a sock to effectively create a sealed box. A sealed box will have a higher rolloff frequency on the low end of the frequency band so that would help to mitigate any booming.
With the MLTL version the 48" version will go lower in frequency so it may tend to boom a bit more than the 31" version. The 31" version will raise the low end cutoff so perhaps room interaction would be lessen. You can also move the MLTL boxes within the room to relieve booming.
Jim
With my minimonitor (JX92S with or without the ribbon tweeter) you may have an in-room booming situation within a small room. You can address this issue via either moving the speakers (you change the interaction with the boundary surfaces) so that the boom is mitigated. Another solution is to stuff the port tube with acoustic foam or a sock to effectively create a sealed box. A sealed box will have a higher rolloff frequency on the low end of the frequency band so that would help to mitigate any booming.
With the MLTL version the 48" version will go lower in frequency so it may tend to boom a bit more than the 31" version. The 31" version will raise the low end cutoff so perhaps room interaction would be lessen. You can also move the MLTL boxes within the room to relieve booming.
Jim
Hi!
Thanks for all the answers. It seems to me that either the mini monitor or the 31" is the way to go. I could actually build both to test the differences as the material cost is minimal. I plan to use mdf. A interesting project.
I have read quite a few threads and some reviews on speakers based on the Jordan driver. However, I still have some questions regarding the sound signature of these speakers.
How are these speakers with regard to dynamics? I understand that they can't deliver bass inpact as a larger speaker. Will a snare drum have a realistic "twack"?
How are the lower midtones? Will Mr. Cash come through with his deep voice?
I also read that HIFI NEWS in a review (19 of 20) of a commercial VTL that it really improved when a large (MF750 or something) was used, especially in the lower regions. Have any of you similar experiences?
Folke
Thanks for all the answers. It seems to me that either the mini monitor or the 31" is the way to go. I could actually build both to test the differences as the material cost is minimal. I plan to use mdf. A interesting project.
I have read quite a few threads and some reviews on speakers based on the Jordan driver. However, I still have some questions regarding the sound signature of these speakers.
How are these speakers with regard to dynamics? I understand that they can't deliver bass inpact as a larger speaker. Will a snare drum have a realistic "twack"?
How are the lower midtones? Will Mr. Cash come through with his deep voice?
I also read that HIFI NEWS in a review (19 of 20) of a commercial VTL that it really improved when a large (MF750 or something) was used, especially in the lower regions. Have any of you similar experiences?
Folke
folkeb said:
Folke,
I am aware of being both boring and unpopular in this view: compare your loudspeakers with real music, not with other people's view of what music should sound like.
In a room the size of yours there will be enough bass to give you a good sensation of its power; you must implement Baffle Step Diffraction correction to get a flat response. (If you don't, the 100Hz to 500Hz region - the fundamental of most notes - will almost certainly be well down compared to the harmonics, the music then sounds thin.)
Snare drum has lots of high frequency components. The JX92S is good at that. Real bass is hearing a diapason organ stop or a bass drum.
MDF is transparent in an annoying way. It makes quite a lot of music sound screechy. It is good for confirming that your design is what you want. There is plenty of discussion on the forum about materials for cabinets.
The Jordans are good enough drivers to respond to as good an amplifier as you choose. So conversely they sound mediocre or bad with a poor amplifier. Forget the detailed A-B comparisons and Subjective vs. Rational debates - amplifiers do make an audible difference to the sound. This is more obvious in some genres of music than others.
Andy
I can second adding BSC to the design - adding it to my MLTLs (48) made the sound fuller and the leaness I'd attributed to the driver vanished completely, giving much more realistic reproduction on voices. And the better the amp, the better they respond, although I haven't presonally found the need for high power.
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