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Thread: Truextent Diaphragms in JBL four-inch compression drivers

  1. #31
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by eso View Post
    I've considered it, but the image issue between the Yuichis and the salad bowls is more due to the vanes in those radials, not unlike the effect of multicells.
    Is this statement based on personal experience, i.e. comparing a pair of radial horns with an without vanes for example... or you read it somewhere... or gut instinct?

    Quote Originally Posted by eso View Post
    ...I'm a wood butcher...
    I've noticed.

    Nice butchering.


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  2. #32
    RIP 2010 scott fitlin's Avatar
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    Thanks 4313, I really wanted to see measurements and hear what you have to say. I am also more than interested in hearing even more of your listening impressions of the True Extent diaphragms.

    This looks promising, and if it is as good as it looks, it, to me, offers a quite reasonable way to upgrade performance.

    Thanks for taking the time.
    scottyj

  3. #33
    Senior Member eso's Avatar
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    Quote Originally Posted by Mr. Widget View Post
    Is this statement based on personal experience, i.e. comparing a pair of radial horns with an without vanes for example... or you read it somewhere... or gut instinct?

    I've noticed.

    Nice butchering.


    Widget
    When I first made the Yuichis I wanted them Primarily to do a side-by-side comparison with the Edgar 350 Tractrix horns. Dr. Edgar and I measured the Yuichis and one of his 350 Tracs with the JBL 2440 drivers I own.

    At a So Cal Horn Group meeting we installed the Yuichis in a set of Edgar Titans with the Seismic sub and a whole group of people listened to the system both ways.

    The Yuichis are the best sounding Radial design I've heard, and they sound much better off-axis than the tracs do. OTOH the Tracs produce are far more 3-D soundstage but for a much smaller sweet spot. You pick your poison and we all know there's many trade-offs to be made.

    I really think the vanes are a big part of the reason, but also the dispersion pattern has something to do with it too. There's only so much information, and if you spread it over a wider area you are going to be sacrificing somewhere to get that extra width. The initial flare outside of the phaseplug in the JBL and Altec drivers something like 12 dregree conic.

    I think of it like looking at a foreshortened hand. The sound from the driver is like that hand with the fingers all together. Spread the fingers apart and what happens? Multicells do this to an even larger extent (I still own my very old tar-filled altec 1005A horns and when I was trying to hifi them I had blocked the outer cells to narrow the pattern and got an improvement in imaging for the effort).

    Enough. My 2¢


    eso

  4. #34
    Senior Member spkrman57's Avatar
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    Round horns have been my poison of choice for the last 10 years!

    Everytime I switch to a other than round horn, I can only be happy for a short time. While I'm seduced by listening to something different, in the long run I live in that 1" sweet-spot" that images like no other horn.

    The closest approximation is how headphones give you the 3D imaging effect.

    Regards, Ron



    Quote Originally Posted by eso View Post
    The Yuichis are the best sounding Radial design I've heard, and they sound much better off-axis than the tracs do. OTOH the Tracs produce are far more 3-D soundstage but for a much smaller sweet spot. You pick your poison and we all know there's many trade-offs to be made.
    JBL Pro for home use!

  5. #35
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by spkrman57 View Post
    The closest approximation is how headphones give you the 3D imaging effect.
    Well, kinda... the headphone experience places the musician or band in your head instead of in front of you. I prefer keeping those drug using creative types out in front where I can see them.


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  6. #36
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    Quote Originally Posted by spkrman57 View Post
    R2 20 ohms
    R1 60 ohms
    C1 .2 ufd

    This is for approx 15 db attenuation/EQ on a 1.6 khz crossover which is the closest I can find for the difference between the JBL 2226 @ 97.4 db/watt and the JBL 2446 @ 112 db/watt if I have the information correct.
    Here you go:

    16 dB added to normalize (grey) the filter plot. If that 3.2 kHz bump sounds objectionable you can try a little notch filter. The 1.8 kHz bump should disappear with your high pass filter.
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  7. #37
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    Quote Originally Posted by eso View Post
    Aren't those just the cutest little radial horns ever?
    Yep!

  8. #38
    Senior Member spkrman57's Avatar
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    Thanks 4313B!

    It looks like really great response up to 16 khz.

    My hearing drops above 14 khz, so I can get away without a tweeter easily.

    I'm already working hard to get some 2446 drivers and the Be diaphrams so I can hear what the actual results in my system!

    Regards, Ron
    JBL Pro for home use!

  9. #39
    Unabashed Speakerholic cosmos's Avatar
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    Help me out here a little please.. To me it appears from the above curves that:

    Without Network: (nominal output approx 100 db)
    1. The 2445/Be goes to about 14KHz before it drops to roughly -5db
    2. The 2445/Be goes to about 17KHz before within -8db
    3. At 20KHz the 2445/Be is -15 db

    With Network: (Nominal output about 84 db)
    1. The 2445/Be goes up to 17KHz within -2db
    2. the 2445/Be is -7db at 20KHz

    So it seems the network works really well at helping HF extension.

    Here's my question: The readings and SPL on the curve is not representative of output at 1W, right? However, if there is correlation to the readings pre and post network addition, it appears the network drops overall output about 15db. If so, it'll have a hard time keeping up with a E145 which is about 98-99db or a 2226 which is about 97db/1W/1M, right?

    With my active setup, that isn't a concern, but with Ron's passive setup it is..

  10. #40
    RIP 2011 Zilch's Avatar
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    2452 is conspicuously MIA here. Not possible?

    ********

    Wayne's selection of HF comp components combines comp AND attenuation to achieve the optimum balance between drivers using a passive crossover:

    http://www.audioroundtable.com/PiSpe...ages/1278.html

    The basic design document is here:

    http://www.pispeakers.com/Speaker_Crossover.doc

    To understand how it operates, see the plots below of EconoWave using the values shown below. Passively, we combined two of them with L-pads to cover the full range. Actively, it doesn't much matter, but there's purpose in using the minimum workable amount of passive attenuation to accomplish the requisite comp with flea-power amps....
    Attached Images Attached Images  

  11. #41
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    Quote Originally Posted by eso View Post
    It's good to know they (Eso built Yuichi horns) are being well used... I wanted them to go to a good home.

    Aren't those just the cutest little radial horns ever?

    Brad, do you know if the TrueXtent diaphrams are available for 2425H drivers (8ohm)?

    eso
    Eso,

    Thanks for the horns - they are getting very good use. I like them A lot.

    As others have posted, they are cute radials. As others don't know as well as I, your woodworking skills are even more stunning to hold then behold. Great work.

    TruExtent does have plans to release diaphragms for JBL 1" drivers but there is no definitive date set for them or any other variant.

    Quote Originally Posted by 4313B View Post

    I know nothing about these Yuichi horns. They look and measure nice. I'll have to hear a pair someday.
    That is a return favor I would be delighted to provide.

    Quote Originally Posted by 4313B View Post
    I really don't enjoy handling other people's beryllium diaphragms and swapping them around in various cores. Everytime one is exposed I get real nervous.
    Understandable - thanks for running them though the paces in spite. It's really appreciated. We simply don't have the appropriate test gear and experience to give them the testing they deserve. Your assistance has been invaluable.

    Quote Originally Posted by Spkrman57
    First off I would like to point out that the 350hz Edgarhorns are mine and are the ones in my avatar.
    If you are going to be that way about it...I'D like to point out the Yuichi's are MINE and not currently in my avatar.

    But don't you worry, another couple years of tests and we should be ready to return the 350hz Edgars to you.

    I (and a few others) have had the good fortune to have heard the TruExtents (on 2445's) on both aforementioned horns and in very unscientific comparison to TAD TD-4001's. The TAD's are a great sounding compression driver. The TruExtent 2245 is as well. I drew no definitive conclusions aside from knowing both outperform any other compressions driver I have heard. I've never heard the 476be. Nor have I heard TAD's newer offerings.

    As far as the horns go, my ears seemingly confirm the comments by Ron & Eso regarding the horns - the farther the listener is from the horns the less intense these differences. I could live happily with either but prefer the Yuichi design - the dispersion sounds more natural to my ears. I've picked the other poison.

  12. #42
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    Quote Originally Posted by cosmos View Post
    Help me out here a little please.. To me it appears from the above curves that:

    Without Network: (nominal output approx 100 db)
    1. The 2445/Be goes to about 14KHz before it drops to roughly -5db
    2. The 2445/Be goes to about 17KHz before within -8db
    3. At 20KHz the 2445/Be is -15 db

    With Network: (Nominal output about 84 db)
    1. The 2445/Be goes up to 17KHz within -2db
    2. the 2445/Be is -7db at 20KHz

    So it seems the network works really well at helping HF extension.
    Yes, these are the same compensation type of filters we've been discussing since people started showing interest in the 4430 back when the forum first started.
    Quote Originally Posted by cosmos View Post

    Here's my question: The readings and SPL on the curve is not representative of output at 1W, right?
    No. 1W input is hella loud.
    Quote Originally Posted by cosmos View Post
    However, if there is correlation to the readings pre and post network addition, it appears the network drops overall output about 15db.
    Right. 15 dB by math, 16 dB by measurement.
    Quote Originally Posted by cosmos View Post
    If so, it'll have a hard time keeping up with a E145 which is about 98-99db or a 2226 which is about 97db/1W/1M, right?
    Probably not, the Edgar horn is quite efficient as shown in #2 where the input levels are equal. An actual network is worked up as a system where all the drivers are measured in their intended mounted positions. The actual corrected attenuation would be determined at that time.
    Quote Originally Posted by cosmos View Post
    With my active setup, that isn't a concern, but with Ron's passive setup it is..
    It depends on how you are going to go active. If you use something like a DEQX then no it wouldn't matter. If you are just going with a simple active filter without any EQ then you will need some kind of passive compensation. Not a 16 dB drop in your case, something more along the lines of a 6 dB drop.

    Bascially you are looking at the response to see how much you have to work with and in this case "flat to 16 kHz" appears to be a reasonable goal. Since the horn/c.d. combination is ~ 6 dB down at ~ 16 kHz you know that you need to do a broadband reduction of about 6 dB to get that "flat" response to ~ 16 kHz.
    Quote Originally Posted by Zilch View Post
    2452 is conspicuously MIA here. Not possible?
    Not really necessary and it is a 1.5" exit compression driver. Additionally it has an MSRP of $1,430 and one would still be stuck with a titanium diaphragm. JBL Pro kind of missed the boat. They got on the boat that was moving all of manufacturing south instead...
    Quote Originally Posted by Zilch View Post
    Wayne's selection of HF comp components combines comp AND attenuation to achieve the optimum balance between drivers using a passive crossover:

    http://www.audioroundtable.com/PiSpe...ages/1278.html

    The basic design document is here:

    http://www.pispeakers.com/Speaker_Crossover.doc
    Thanks for posting those links. Ron sent them to cosmos and a bunch of other people last Friday via email but that doesn't do anyone any good reading the forum.

  13. #43
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    4313B:

    Thanks for sharing Greg's raw frequency response measurement of the 476Be on the Everest horn.

    Could we also have the raw impedance response measurement?

  14. #44
    Unabashed Speakerholic cosmos's Avatar
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    Quote Originally Posted by 4313B View Post
    Probably not, the Edgar horn is quite efficient as shown in #2 where the input levels are equal. An actual network is worked up as a system where all the drivers are measured in their intended mounted positions. The actual corrected attenuation would be determined at that time.It depends on how you are going to go active. If you use something like a DEQX then no it wouldn't matter. If you are just going with a simple active filter without any EQ then you will need some kind of passive compensation. Not a 16 dB drop in your case, something more along the lines of a 6 dB drop.
    Thank you. That's exactly what I thought. Currently, I am using a Behringer DCX2496, but intend to go to a fixed tube 18db crossover (Steve Bench design) shortly. However, my intention was to add a passive EQ, like discussed, to either system once I have some idea how much compensation is needed.

    Of interest, is the change not only in output, but in slope on the yuichi in relation to the other horns. When we listened to both Yuichi horns (Ricks' A290S and Brads' A290) and Ron's Edgars, everyone there perceived lower HF output with Brads' (the ones you tested). While the two Yuichi types looked very much the same, there are some minor differences. Therefore, it's possible that the curve shown in #2 is not representative of all yuichi horns. I'd be willing to bet Ricks' A290S have a flatter curve in respect to HF extension. Of course, this is something that should be able to be remedied with the right network approach.

    Quote Originally Posted by 4313B View Post
    Bascially you are looking at the response to see how much you have to work with and in this case "flat to 16 kHz" appears to be a reasonable goal. Since the horn/c.d. combination is ~ 6 dB down at ~ 16 kHz you know that you need to do a broadband reduction of about 6 dB to get that "flat" response to ~ 16 kHz.
    No doubt, based upon looking at those curves, the horns I built will be different and will require a different circuit for compensation. Just like I suspect Ricks and Brads horns require different compensation values.

  15. #45
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    Quote Originally Posted by Wilhelm P. View Post
    4313B:

    Thanks for sharing Greg's raw frequency response measurement of the 476Be on the Everest horn.

    Could we also have the raw impedance response measurement?
    Sure... but... I lied, that wasn't the Everest II horn, it was the 1400 Array Horn.

    This is for the 1200FE and 1400 Array Horn with 476Be system. Call it the 1200 Array II if you want.

    The Everest II data is the second two plots. Raw data and data with actual network.

    I changed the scales to match the other plots in this thread. Also note that the Everest II raw data is higher resolution.
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