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Thread: 1400Nd Vs 1200Fe (2- way with 1.5 horn)

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  1. #1
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    1400Nd Vs 1200Fe (2- way with 1.5 horn)

    Hello everybody,
    In order to build a second system, I'd like your point of view please
    I already have, some 1400Pro and a 1400Nd reconne kit, 2450SL, H9800 Behringer clones and nice Woody's Arai 1.5
    My first idea was to build some enclosure with the same volume as the M9500: 115 liters (4.1 cu ft) 28 Hz tuning (lower LF), but if it's possible to get the same (or better) result in a smaller box: - it's better for my living room
    Then i think to the 1200Fe even if it's difficult to find... (but i have time )
    According to you, which of these two speaker is better until more or less 700Hz -750Hz?
    Thank you,

    Didier

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    Quote Originally Posted by Didier View Post
    Hello everybody,
    In order to build a second system, I'd like your point of view please
    I already have, some 1400Pro and a 1400Nd reconne kit, 2450SL, H9800 Behringer clones and nice Woody's Arai 1.5
    My first idea was to build some enclosure with the same volume as the M9500: 115 liters (4.1 cu ft) 28 Hz tuning (lower LF), but if it's possible to get the same (or better) result in a smaller box: - it's better for my living room
    Then i think to the 1200Fe even if it's difficult to find... (but i have time )
    According to you, which of these two speaker is better until more or less 700Hz -750Hz?
    Thank you,

    Didier
    While i haven't heard the 1200fe i have 1400nd in some monitors i am building, 2 per side and to me these are the best bass driver i've ever heard regardless of price. Everyone that has listened to them loves what they do.


    joe.

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    Can you model the bass response?

    Jbl typically did the tuning empirically meaning they would iteratively try different enclosure sizes and tuning until they were satisfied the voicing would suit the market

    Quite a while back the IET was discussed

    As l recall In an interview Bessel tuning was adopted

    Anacdotally the Japan Audio market like tight fast bass.

    But you may not have the preference.

    What l am saying is with diy do as you wish but if you can model your design in a simulator then you have a fairly reliable means of assessing the impact of a smaller box

    Typically making a bass reflex box a “bit” smaller will only kill the extension
    And the ear is sensitive to that. If you do make the box smaller by more than 10% you wil need to re tune the port.

    Have you thought about making the enclosure deeper to hide the internal volume?

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    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by JoeNelis View Post
    While i haven't heard the 1200fe i have 1400nd in some monitors i am building, 2 per side and to me these are the best bass driver i've ever heard regardless of price. Everyone that has listened to them loves what they do.


    joe.
    Joe, I'm really glad you like them.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Quote Originally Posted by speakerdave View Post
    Joe, I'm really glad you like them.
    I sure do speakerdave, simply stunning drivers.


    Joe.

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    Now Dieter it's clear! . Rob, I think I'll fit the reconne in the 1400Pros
    Interresting to see that the curve seems better with 80L than more . I thought 120L was better with this speaker...
    From elsewhere, close to the 1200Fe in 60L.
    Didier

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    Hi Didier,

    I think the curve may extend deeper with a larger cavity hence the larger cavity when JBL made the K2 speakers. This was probably the best way back then as DSP was not readily available and amps were expensive compared to today.


    Today we can easily correct the earlier fall off in the smaller cabinet as long as the cone motion and power capacity is not limiting. For me it was not.

    The important thing if using smaller cavity is that the curve is smooth and falls off in at even pace. That makes it simple to correct with a DSP and the LE1400H delivered just that and I have no doubt your 1400nd will do the same, if not better.

    Dependent on placing you will also get some bass support from corner and/and potential floor location. My curve is near field so none of that is visible. My ports were rear firing and that also helped in my application with some support from the corner.

    Kind regards and good luck
    //Rob
    The solution to the problem changes the problem.
    -And always remember that all of your equipment was made by the lowest bidder

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    Senior Member RMC's Avatar
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    Hi Didier,

    RE: 115 liters (4.1 cu ft) 28 Hz tuning (lower LF), but if it's possible to get the same (or better) result in a smaller box: - it's better for my living room


    I modeled in Winspeakerz and also in Win ISD Pro (2016) softwares the 1400 Pro in a 115 L. box with tuning at 28 Hz as you mentioned, and the results are NOT that good in the bass range... Tuning at 28 hz is way too low for this box/driver combo and puts more undue strain on the woofer.

    The "lower LF" you mention are at a much reduced level compared to the rest of response and yield higher woofer excursion than necessary. Response curves I get in both softwares show a pretty early dropping response and are as follows:

    Winspeakerz: almost 0 db at 500 hz, then response is down -1.5db @200hz, -4.5db@100hz, -8db@50hz, almost -9db@30hz.
    Win ISD Pro (with the usual Ql 7 box loss assumption): same as above at 500 and 200 hz, -4db@100hz, almost -8db@50hz and about -9db@30hz.

    This is far from flat bass response and results in weak bass compared to your woofer higher frequencies level... In other words that design is "stretching the sauce" in the bass range. That speaker should sound very mid-bassy up to your 700-750 hz limit. One would possibly need to use speaker corner placement in order to bring up the low end.

    Tuning the same box at 50 hz brings the lows higher (around 50+ hz) but on the same level as higher frequencies (except for a dip of 2.5 db around 90 hz in lower mid-bass) and F3 at 46-7 hz in both softwares. Personnaly, I would much prefer this type of curve than the other one above. An 85 L. (3 cu. ft.) box tuned around 55 hz would also bring the lows at same level as higher frequencies and yield a quite similar type of response but bring the lows higher at 60 hz, a 2 db dip around 100 hz and an F3 @ 51 hz in both softwares.

    This shows to me this driver isn't really capable of very low decent output (not subwoofer class) wheter by low tuning or larger cabinet size, but still OK for general purpose low frequency reproduction down to about 50 hz.

    The wish of a large driver, in small box with deep low-end is an endless story but not often compatible with the laws of physics unfortunately. Compromise is the name of the game here. At first sight, the T/S parameters of the 1400ND MAY appear to show more hope for your wish, however only modeling it in software will tell for sure if this is the case... I have not had time to model that possibility yet. Let me know if you need that, I'll see if I can find some time. Regards,

    Richard

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    The way I read the original post was that poster planned to put the 1400nd cone kits in the 1400 pro frames, which are the same.

    The only JBL speaker with one 1400nd is the S7500. That would be a fruitful study. I used 1400nd's in pairs in the M9500 configuration, and experimented with singles in the two different boxes. The S7500 was made for the Japanese market, where there is a) different taste in bass style, and b) small rooms, with corresponding differences in room gain, for hi fi. Long story short, the 1400nd was meant to be used in pairs in most cases.

    The 1200fe was used singly in the 4429. That would also be worth studying, I would think.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Hi Didier,

    An 80 L. box with 30 hz tuning isn't a good idea in my view even if you compensate with DSP (i.e. equalization) because it requires more power which leads to more distortion caused by increased cone travel...

    Winspeakers response for such a box: a decrease in level starting around 200hz, -1.5db@100hz, -3db@50hz, -6db@32-33hz. This is quite similar to earlier modelings I did for you and my same comments apply here.

    Since computer modeling with T/S already assumes one boundary speaker placement (e.g. floor) you would need at least one more boundary (e.g. floor and back wall) or maybe corner placement (three boundaries) to increase the low-end at an acceptable level compared to the higher frequencies reproduced by the 1400nd driver.

    A steep high-pass filter is usually required as E-V doest it with their "step-down mode EQ" and there are other conditions like, if my memory is correct, tuning half an octave below "normal", not just any frequency below... You should read more on this issue.

    The speaker placement option requires no added power or DSP (i.e. its a FREE boost from the room!). If you were to go Rob's way then I would suggest you take the room gain option first rather than lower tuning.

    Remember, as fabulous as it may be, the 1400nd is NOT a 2245H subwoofer...

    Finally, the "not bad" in my previous post did not mean "so and so" but rather still quite good or acceptable.

    Regards,

    Richard

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    Dang. Amateur speakerdave's Avatar
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    Quote Originally Posted by RMC View Post
    . . . . Remember, as fabulous as it may be, the 1400nd is NOT a 2245H subwoofer . . . .
    +1

    GT has commented in these forums that the limiting factor is the small roll surround, so alignments calling for VLF EQ would be counter indicated, I should think, especially if reaching below Fb.
    "Audio is filled with dangerous amateurs." --- Tim de Paravicini

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    Before proceeding to the next instalment of E-V/Keele "step-down mode" LF increase, I must say I disagree with Ian's following statement in post # 33:

    "Perhaps one point to consider on higher tunings is the inevitable hump in the responses due to room gain"

    Higher tunings don't necessarily lead to a bass bump with or without room gain. Excessively high tunings combined or not with more than one boundary (half-space or 2 Pi) speaker placement would lead to a bass bump, however this is NOT inevitable as Ian mentions.

    The boxes I modeled here for Didier had quite reasonably flat response, even in the bass range, and "discrepancies" in response were noted (nothing to pull one's hair off).

    As for room gain, well, one more time, if you read the help files in Win ISD Pro you will see that driver radiation into half-space (2 Pi) is assumed when modeling a driver with software using T/S parameters. In other words, one boundary speaker placement is already "built-in" the calculations/modeling:

    "The data calculated from the Thiele-Small parameters refers only to the LF performance of the system; ... Further, the analysis assumes that the loudspeakers will be locating adjacent to a single reflective boundary, such as the ground, or a wall. " (P. 106). "Conventional LF alignments using Thiele-Small parameters assume 2 Pi radiation." (P. 295). John Eargle (JBL), Handbook of Sound System Design, ELAR, 1989. BTW "The author wishes to acknowledge John Hoge, who studied the outline and manuscript of the book and made many helpful suggestions." In addition to Eargle, John hoge is also a well-known Loudspeaker Engineer (CTS, JBL, etc.).

    What does that mean? For normal or usual speaker placement adjacent to ONE boundary, there is no additional room gain than the one already given from full space to half-space (i.e. the usual home situation). Therefore, we're far from the "inevitable bump in the response due to room gain". The addition of a second boundary (e.g. wall) or third boundary (corner placement) could cause that along with excessively high box tuning or not...

    The probabilities of excessive room gain in normal or usual speaker placement situations appear somewhat thin: "The actual home loudspeaker environment is apt to be somewhere between a 4 Pi and 2 Pi condition,...". John Eargle, Loudspeaker Handbook, Chapman & Hall, 1997, Aspects of the Home Listening Environment, P. 291. This would indicate LESS initial room gain than theory suggests (i.e. +6 db from full space to half-space), so again we would be a little further from too much room gain...

    Finally, Martin Colloms (author of High Performance Loudspeakers, 1991) seems to confirm Eargle's last quote above: "... if you accept my contention that for typical rooms there is a progressive averaged bass lift of between 4.5 and 5.5 db/octave below 70 hz than a free field, ...". Speaker Builder, 4/92, P. 72, which is a little LESS than theory suggests. He wrote that in the magazine the year after his book. Regards,

    Richard

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    Hi Didier,

    The T/S I used for modeling are the same that Dieter has posted. Don't forget in Win ISD to change the default QL 10 to a more appropriate QL 7, and don't choose the default BB4/SBB4 alignments but rather the QB 3 alignment in the menu. That should cure the weird looking response curve.

    Richard

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    Hi Didier and Rob,

    Here is how Electro-Voice describes, in simpler terms than D. B. Keele, the "Step-Down" operation (lower tuning than normal + EQ) to get lower bass from a smaller box:

    "... the "step-down" mode, which approximates a B6 Thiele alignment. Step down is a good way to extend system low-frequency response by increasing amplifier power at certain frequencies instead of enclosure size.

    In step down, the enclosure is tuned to a lower-than-normal frequency. This increases system output at the new tuning frequency and reduces output slightly in the region of original tuning. The smoothly falling response which results can be equalized to provide a new system 3-db-down point that is about 0.7 that of the original. To achieve a similar response extention without equalization would require an enclosure at least twice the size.

    In the step-down mode, system input is increased at the lower end of the operating range, by a maximum of 6 db close to the new tuning frequency. Note that this boost does not affect system instantaneous peak output, which is related only to the speaker's linear displacement ability and effective diaphragm area."

    The frequency where an increase is applied (EQ) is called a "peak-boost frequency". According to E-V, other frequencies sufficiently close, within + or - 5%, will provide no significant performance compromise.

    With regards to Subpassband speaker protection (the other side of the coin) here is what E-V says:

    "Below the enclosure tuning frequency, cone excursion increases rapidly. Since acoustic output is also falling rapidly, there is no utility in driving the system with signals much below the tuning frequency. (...). ... high output systems, especially subwoofer systems, should be protected by a high-pass filter with a 3-db-down corner frequency of about 0.8 the enclosure tuning frequency... Below the corner frequency, a rolloff of 12 db per octave is usually sufficient."

    So, an amplitude boost followed by a bandwidth cut at the very low end, that E-V calls "boost-and-cut equalization". "The equalization has no effect on the large-signal output but does have the effect of separating the small- and large- signal curves except at the very top of the frequency range shown."

    Quoted from: Electro-Voice, Pro Sound Facts, #7, oct. 1984, pages 3 and 5

    See Figure 3 in the XEQ-2 crossover/equalizer data sheet to look at examples of increases applied at various frequencies (+ 6 db with a filter Q of 2).

    E-V did not mention, in this context, the LF room gain possibility based on speaker placement.

    More interesting stuff to come from E-V and D. B. Keele, stay tuned!

    Richard

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    Dear all,

    I have to do some remorse here. I checked the data a little more thorough and there is real difference between LE1400H and 1400Nd, albeit having the allegedly the same cone. I have never had the 1400Nd so my findings were based solely upon the LE1400H.

    Attached is a TS summary of the 14” squarcle drivers that I can find data on. LE1400H has a higher Fs and lower VAS which may explain the differences. And mine were tuned to 32Hz not 27Hz as stated Before.

    Maybe someone here can fill in the blanks, that would be interesting


    That means that the 1400Nd probably do need a bigger box than LE1400H to produce a nice curve. Sorry.

    HoweverI do still stand by the recommendation to do real life tests before commissioning final cabinets as there are many moving parts here. Placement and shape of vents do matter and well-built test box is not much work/money compared to living room standard final cabinets.

    And of course using lousy leaking test boxes is useless but as you can totally discard the finish of the test box there is no reason not to use lots of glue and insert real bracing. I typically build slightly larger boxes and experiment with volume buy introducing volume consuming object in the box or just install a shelf to make it smaller.

    The EV “step-down”alternative look real interesting, I need to dig deeper into that.

    -Still learning :-)


    Kind regards
    //Rob

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