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Thread: Jbl hla 4897

  1. #1
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    Jbl hla 4897

    does anyone know the port tuning for HLA 4897 sub?




    Ari

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    Senior Member RMC's Avatar
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    Hi Ari,

    I Have some info for you about this but its too late now gotta go sleep... I'll be back sometime tomorrow. Regards,

    Richard

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    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by hlaari View Post
    does anyone know the port tuning for HLA 4897 sub?




    Ari
    You have accomplished your 4348 copy?How about HLA4897?
    46 lover

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    Hi Ari,

    I have most of the JBL documentation for the HLA Series and note they've never stated specifically a particular box tuning frequency for the 4897 (i.e. "box tuning is..." or "LF system tuned at ...").

    However, such frequency may be inferred from information given in some of their documents:

    - JBL HLA Series Tech Note V. 1, N. 23 (section Performance of the subwoofer system)

    It appears to be the 25 hz mentioned in that text and also look at figure 8

    - HLA 4895 & 4897 Owner Manual (section Linear Dynamics Aperture)

    "... subwoofer port designs. At 25 hz, this provides for ..." (P. 2)

    The JBL DSC 280 Digital System controller is recommended for use with the HLA System (P.7).

    X-OVER section: "The subwoofer's high-pass is set at 28 hz. These are locked by the OEM programmer to prevent damage." (P.9)

    Transducer Specifications and power levels section: SUB 2242HPL, Frequency in Hz 35 - 120 (P. 15) The 4897A version used the 2258H.

    - 4897 and 4897A Spec sheets: the recommended bandpass 27 - 120 hz is the same for both versions; Note the 98 db sensitivity applies to 35 - 120 hz (not 25, 27 or 28 hz - 120 hz) and frequency response 34 - 150 hz ± 3 db is for 4 units arrayed together, these also applying to both versions.

    - 4897 and 4897A Technical Manuals: they confirm the above info from Spec Sheets.

    So tuning seems to be 25 hz, recommended bandpass from 27 hz, high-pass filter set at 28 hz, LF F3 response from 34 hz (4 units) with 98 db woofer sensitivity from 35 hz...

    I hope this information is useful to you. Regards,

    Richard

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    Quote Originally Posted by RMC View Post
    Hi Ari,

    I have most of the JBL documentation for the HLA Series and note they've never stated specifically a particular box tuning frequency for the 4897 (i.e. "box tuning is..." or "LF system tuned at ...").

    However, such frequency may be inferred from information given in some of their documents:

    - JBL HLA Series Tech Note V. 1, N. 23 (section Performance of the subwoofer system)

    It appears to be the 25 hz mentioned in that text and also look at figure 8

    - HLA 4895 & 4897 Owner Manual (section Linear Dynamics Aperture)

    "... subwoofer port designs. At 25 hz, this provides for ..." (P. 2)

    The JBL DSC 280 Digital System controller is recommended for use with the HLA System (P.7).

    X-OVER section: "The subwoofer's high-pass is set at 28 hz. These are locked by the OEM programmer to prevent damage." (P.9)

    Transducer Specifications and power levels section: SUB 2242HPL, Frequency in Hz 35 - 120 (P. 15) The 4897A version used the 2258H.

    - 4897 and 4897A Spec sheets: the recommended bandpass 27 - 120 hz is the same for both versions; Note the 98 db sensitivity applies to 35 - 120 hz (not 25, 27 or 28 hz - 120 hz) and frequency response 34 - 150 hz ± 3 db is for 4 units arrayed together, these also applying to both versions.

    - 4897 and 4897A Technical Manuals: they confirm the above info from Spec Sheets.

    So tuning seems to be 25 hz, recommended bandpass from 27 hz, high-pass filter set at 28 hz, LF F3 response from 34 hz (4 units) with 98 db woofer sensitivity from 35 hz...

    I hope this information is useful to you. Regards,

    Richard


    Thank you for the info
    so it look´s like the 4897 are tuned similar like the 4645B/C subwoofers at 25Hz

    I think at this boxes would perform better with 2269




    Ari

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    Quote Originally Posted by martin_wu99 View Post
    You have accomplished your 4348 copy?How about HLA4897?

    I am still working on my 4348
    they are going to be different from the original version, with different driver parts (W1500H, dual 251J, 476Be and 045Mg)
    this system will be fully active

    I think at I will call them 4348MKII




    Ari

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    Hi Ari,

    RE: "I think at this boxes would perform better with 2269"

    I modeled quickly in Winspeakerz the 2269 in 8 cu.ft. box tuned at 25 hz and also tuned at 30 hz. You have below both results on the same graph, bottom curve is Fb 25 hz and top curve is Fb 30 hz.

    In my view, the top curve (30 hz) is better and flatter bass wise.

    There isn't much gain to make bandwidth wise tuning at 25 hz since its at a quite lower output... Regards,

    Richard


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  8. #8
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    I modeled quickly in Winspeakerz the 2269 in 8 cu.ft. box tuned at 25 hz and also tuned at 30 hz. You have below both results on the same graph, bottom curve is Fb 25 hz and top curve is Fb 30 hz.

    In my view, the top curve (30 hz) is better and flatter bass wise.

    There isn't much gain to make bandwidth wise tuning at 25 hz since its at a quite lower output... Regards,

    Richard


    I read on the forum at you like the horn system 4895?
    can you give me some review on them




    Ari

  9. #9
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    Hi Ari,

    RE: post # 8

    Martin Wu99 had a thread about favorite JBL speakers (it didn't say hi-fi/control room only). While most people listed conventional systems like the 43 series, I voted for the HLA Series alone! Simply because it is really different and high performance, even if it doesn't belong to home hi-fi.

    Three years of engineering went into this flagship touring system: cabinet engineering, Transducer engineering, Acoustical engineering, vent engineering, etc. for only two complementary "boxes"! This is amazing. I'm aware of no other JBL system that went this far to leave no stone unturned...

    When you talk about starting from a clean sheet of paper, and many do claim this in their marketing, well here this is truly it for the HLA series. The number of new technologies and ways involved in the making is unmatched in my view, plus these can readily be seen.

    Moreover, the flatness of their frequency response, for that type of system, is remarkable. A well known JBL Sound Contractor was also involved for field testing of the prototypes and feedback to engineering. The initial prototype seen was two-way horn, then called AAlto system, but was a three-way horn system when released as 4895.

    At 1997 prices, having a pair (4895/4897) of these systems on each side cost $25,000.USD. I never owned it nor heard it though...

    At a Belgium music festival in July 1997 where the HLAs were used (maybe their launch in Europe), Bill Gelow, Director of Acoustical Engineering at JBL who worked on the HLA Series was on site, I assume to make sure everything went ok and to assess system performance in a real touring sound situation with a crowd of 50,000 people.

    Btw under the glass on my desk I have a nice pic of the 4895. Regards,

    Richard

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    I have seen this Aalto system one time one eBay for some years ago, I think at they did have dual 2251j and 2451SL?
    I just remember at the distributor in Iceland for JBLpro did hear them on some show in US for some 20 year ago and they said at they sound amazing!

    I have always liked the design of the HLA series, I own both the 14" 2254j and 10" 2251j drivers


    Ari

  11. #11
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    Hi Ari,

    I sure like the HLA design too, as well as the engineering/innovations that went into these.

    The usually recommended number of each HLAs, as seen in the owner manual, for most applications is two tops (4895) for one bottom (4897). At the Belgium music festival previously mentioned they followed that 2 to 1 recommendation by using 48 top and 24 bottom HLAs.

    Compare pictures posted here of left side units between original HLA product brochure I have and the AAlto system ad. The units are not exactly the same, something seems to be "missing" on the AAlto unit: 3rd way? Also the JBL name does not appear on the AAlto system. These things made me believe the left AAlto unit may be a prototype for testing in the field.

    The right side AAlto unit seen on the ad is a bit of a mystery. Looks like a large box tilted forward inside the tube frame. Maybe a prototype HLA subwoofer? However, the sub cabinet put on the market sure doesn't look like this...

    The EQ magazine text about the HLAs shows 1997 retail pricing, I was wrong re 25K, its rather $23,000. USD for top/bottom on each side...

    Btw, Audio Analysts JBL Sound Contractor in Colorado, USA mentioned in the AAlto system ad was purchased around 2011 as I recall by Canada's Solotech which moved it to Las Vegas since some artists they do sound/lighting for had longer term entertainment commitments in that city. Regards,

    Richard

    PICTURE CREDITS: AAlto picture from Pro Sound News, Sept. 1996; HLA text with pricing from EQ Magazine, Jan. 1997, P. 74; close picture of the 4895 from JBL, HLA Series Brochure, 1996.


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  12. #12
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by hlaari View Post
    I am still working on my 4348
    they are going to be different from the original version, with different driver parts (W1500H, dual 251J, 476Be and 045Mg)
    this system will be fully active

    I think at I will call them 4348MKII




    Ari
    I think your 4348MKII has no business with original 4348,it should be called 4358
    46 lover

  13. #13
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by RMC View Post
    Hi Ari,

    RE: post # 8

    Martin Wu99 had a thread about favorite JBL speakers (it didn't say hi-fi/control room only). While most people listed conventional systems like the 43 series, I voted for the HLA Series alone! Simply because it is really different and high performance, even if it doesn't belong to home hi-fi.

    Three years of engineering went into this flagship touring system: cabinet engineering, Transducer engineering, Acoustical engineering, vent engineering, etc. for only two complementary "boxes"! This is amazing. I'm aware of no other JBL system that went this far to leave no stone unturned...

    When you talk about starting from a clean sheet of paper, and many do claim this in their marketing, well here this is truly it for the HLA series. The number of new technologies and ways involved in the making is unmatched in my view, plus these can readily be seen.

    Moreover, the flatness of their frequency response, for that type of system, is remarkable. A well known JBL Sound Contractor was also involved for field testing of the prototypes and feedback to engineering. The initial prototype seen was two-way horn, then called AAlto system, but was a three-way horn system when released as 4895.

    At 1997 prices, having a pair (4895/4897) of these systems on each side cost $25,000.USD. I never owned it nor heard it though...

    At a Belgium music festival in July 1997 where the HLAs were used (maybe their launch in Europe), Bill Gelow, Director of Acoustical Engineering at JBL who worked on the HLA Series was on site, I assume to make sure everything went ok and to assess system performance in a real touring sound situation with a crowd of 50,000 people.

    Btw under the glass on my desk I have a nice pic of the 4895. Regards,

    Richard
    Geat! seems you are the first man who rank HLA 4895 on JBL top list.
    46 lover

  14. #14
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by RMC View Post
    Hi Ari,

    I sure like the HLA design too, as well as the engineering/innovations that went into these.

    The usually recommended number of each HLAs, as seen in the owner manual, for most applications is two tops (4895) for one bottom (4897). At the Belgium music festival previously mentioned they followed that 2 to 1 recommendation by using 48 top and 24 bottom HLAs.

    Compare pictures posted here of left side units between original HLA product brochure I have and the AAlto system ad. The units are not exactly the same, something seems to be "missing" on the AAlto unit: 3rd way? Also the JBL name does not appear on the AAlto system. These things made me believe the left AAlto unit may be a prototype for testing in the field.

    The right side AAlto unit seen on the ad is a bit of a mystery. Looks like a large box tilted forward inside the tube frame. Maybe a prototype HLA subwoofer? However, the sub cabinet put on the market sure doesn't look like this...

    The EQ magazine text about the HLAs shows 1997 retail pricing, I was wrong re 25K, its rather $23,000. USD for top/bottom on each side...

    Btw, Audio Analysts JBL Sound Contractor in Colorado, USA mentioned in the AAlto system ad was purchased around 2011 as I recall by Canada's Solotech which moved it to Las Vegas since some artists they do sound/lighting for had longer term entertainment commitments in that city. Regards,

    Richard

    PICTURE CREDITS: AAlto picture from Pro Sound News, Sept. 1996; HLA text with pricing from EQ Magazine, Jan. 1997, P. 74; close picture of the 4895 from JBL, HLA Series Brochure, 1996.


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    Do you have any ideas that make HLA series into home hifi?
    46 lover

  15. #15
    Senior Member martin_wu99's Avatar
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    Quote Originally Posted by RMC View Post
    Hi Ari,

    RE: post # 8

    Martin Wu99 had a thread about favorite JBL speakers (it didn't say hi-fi/control room only). While most people listed conventional systems like the 43 series, I voted for the HLA Series alone! Simply because it is really different and high performance, even if it doesn't belong to home hi-fi.

    Three years of engineering went into this flagship touring system: cabinet engineering, Transducer engineering, Acoustical engineering, vent engineering, etc. for only two complementary "boxes"! This is amazing. I'm aware of no other JBL system that went this far to leave no stone unturned...

    When you talk about starting from a clean sheet of paper, and many do claim this in their marketing, well here this is truly it for the HLA series. The number of new technologies and ways involved in the making is unmatched in my view, plus these can readily be seen.

    Moreover, the flatness of their frequency response, for that type of system, is remarkable. A well known JBL Sound Contractor was also involved for field testing of the prototypes and feedback to engineering. The initial prototype seen was two-way horn, then called AAlto system, but was a three-way horn system when released as 4895.

    At 1997 prices, having a pair (4895/4897) of these systems on each side cost $25,000.USD. I never owned it nor heard it though...

    At a Belgium music festival in July 1997 where the HLAs were used (maybe their launch in Europe), Bill Gelow, Director of Acoustical Engineering at JBL who worked on the HLA Series was on site, I assume to make sure everything went ok and to assess system performance in a real touring sound situation with a crowd of 50,000 people.

    Btw under the glass on my desk I have a nice pic of the 4895. Regards,

    Richard
    Pos once recommended SRX738,wrager think The AE series work well, AM6215/95 can be used as Center Channel of HT, and STX 825 or STX 835,Their spec sheets look quite flat and reasonably extended,SRX 725 is quite musical.
    How do you think of these speakers?
    46 lover

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