Page 2 of 3 FirstFirst 123 LastLast
Results 16 to 30 of 41

Thread: Need help selecting drivers for DIY 3 way or 4 way music/home theater speakers

  1. #16
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    1,405
    Todd,

    RE Never heard of a 251J and don't see specs on it anywhere

    Haven't found any either, surprising since its a "named" JBL driver with model number and sticker, not an oem type having only a part number.

    RE Crossing the Heil over at 1kHz is a mistake.

    I agree, based on Eargle's Loudspeaker Handbook showing a late 1998 MLSSA response graph for the Heil (don't know which version). At about 1khz its down 5db, 1.3khz up 4 db, say 1.5khz down 5 db, and at 1.7khz or so its back up on the line for good. So below 1.7 khz its a rather "bumpy ride". However, from that last frequency its pretty flat (but for 2db peak at 18-19 khz) out to 20khz where it rolls-off sharply. Off-axis curves are also given but the applicable angles are not mentioned. Often such angles might be 15/30į or 30/45į, pick the one you think fits best according to your own experiments. Anyhow the worst case response shown for off-axis is about 3 db down near the top end. Not bad!

    RE Still, there are those that would say that this is too high a frequency for a ~10" speaker based on the wavelength.

    Well, based on Weems' speaker building book the upper limit for a 10" is 1.5 khz. As for Eargle's, its a little more detailed: with a Di 6db (the usual standard) its 1100 hz, but stretching it to Di 10db then its 1650 hz. So at 2,150 hz its somewhat high but since you mention always sit in the sweet spot, then the actually more directional 10" is being less noticed i guess.

    Don't worry i'm a "cheater" too. Having a pair of boxes with a 10" (special cone for warmer sound) along with a horn tweeter which can be crossed over as low as 1.5khz, but actually done about 2khz for little increased power. That one isn't a hi-fi style box, rather a small sound reinforcement one i can biamp with the 2205H cabs for noise making, or simply use it as stand alone, like a "side fill". In my case the more directional woofer is matched with a more directional horn tweeter, so reduced driver coverage pattern issue.

    As a separate note, i'm surprised following your post, as well as Widget's, that nobody mentioned the McCauley 6222 the OP has shown, maybe its outside the comfort zone? I quickly checked it before, having their catalog within arms reach, and saw some potential there (needing confirmation as usual), and depending on how/where he decides to go. Unfortunately this doesn't mean i magically have more time available.

    Richard

  2. #17
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    4,977
    JBL 251J info




    Sourced From:


    Name:  Screenshot 2022-01-31 103946.jpg
Views: 213
Size:  39.4 KB

    You know, it's a good idea to familiarize ones-self with this forums extensive resources.


  3. #18
    Administrator Mr. Widget's Avatar
    Join Date
    Apr 2003
    Location
    San Francisco
    Posts
    9,255
    Quote Originally Posted by Earl K View Post
    You know, there's really no excuse for not familiarizing yourselves with this forums resources.




    Widget

  4. #19
    Senior Member
    Join Date
    Apr 2003
    Location
    GTA, Ont.
    Posts
    4,977
    Quote Originally Posted by Mr. Widget View Post



    Widget

    I just changed my message ( but please let yours stand ).


  5. #20
    Senior Member
    Join Date
    Jul 2003
    Location
    Orange County, CA
    Posts
    3,431
    Quote Originally Posted by RMC View Post

    However, from that last frequency its pretty flat (but for 2db peak at 18-19 khz) out to 20khz where it rolls-off sharply. Off-axis curves are also given but the applicable angles are not mentioned.

    Richard

    Been there fixed that. I created diffraction lenses for the Heils to remove the peak and smooth out the very top end. BTW, I also block the rear wave with a piece of acoustic material attached to the back of the Heil.





    The wedges actually bring up the lower end a bit.
    Attached Images Attached Images  

  6. #21
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,696
    http://www.mccauleysound.com/product...ons.cfm?ID=109

    "As a separate note, i'm surprised following your post, as well as Widget's, that nobody mentioned the McCauley 6222 the OP has shown"
    LOL. I stand by my initial impression and guesses about this driver... & I'd take that 2.5KHz upper 3dB spec with a grain of salt, and I've seen no response plots for the 6222:

    "...Also, you wouldn't have to drive the 10" units as hard/low. The Gauss units might work, if they spec out for such duty...might have to drive them separately."

    "Gauss? was thinking of that as the mid-bass element... I have no idea how/if it would match up with the Heil driver on it's own."

  7. #22
    Senior Member
    Join Date
    Apr 2003
    Location
    Australia
    Posts
    7,406
    Quote Originally Posted by saabracer23 View Post
    Efficiency isnít necessarily all that crucial. Iím sure anything that is built will be plenty efficient. The room is about 16í wide and 23í long. There is plenty of amplifier power, while running active each driver will have 300-400 watts each depending of the amplifier dedicated to that driver. If I get the passive crossovers setup Iíll then switch over to some Yamaha amplifiers I have rated at 925w at 8 ohms and 1400 at 4 ohms, so plenty of power.

    Fir frequency response Iíd like them to be a true full range speaker, for music my thoughts are running the speakers only so hopefully theyíll make it to 30hz (-3db) or so give or take a few hz. If Iím really in the mood for bass I can kick in the sub1500s as Iím sure they can do music justice. For HT the plan is to kick in the 18s and cross them to the mains at somewhere between 50-70hz. So these main speakers will start rolling off at that crossover point. Cabinet size would be whatever is optimal for the drivers picked. Theyíll likely be behind an acoustically transparent screen/wall. The 18Ē sub cabinets will be 14 cubic feet afrer subtracting port and driver volume, so pretty large.


    ďDepending on what you want to your design to do some drivers might suit and some might not.Ē

    Basically Iím after the 10Ē mid driver that will give me the cleanest most coherent midrange, where vocals will be as clean as possible. If at the same time they can give some good impact in the midbass region that would be a plus, but Iím sure the woofer they cross to can handle most of that if needed. Same goes for the woofer, I would hope for tactical clean bass with very little decay. I donít want boomy, but I know that has a lot to do with the cabinet. On the tweeter, nobody has said not to use the Heil, so I may just go with that. I really like it, itís fairly efficient and sounds good while being able to being able to cross low. Iíll have to double check, but I may have the mid and tweeter from the SK2-3300 as well, maybe those would be a better option than the Heil?

    Indeed you are correct, building test boxes and taking measurements with REW would get me the answers I need. With twins that are a couple months old at the moment my time is externally limited, so if there was someone that had some time with these drivers I figured they might be able to save me time. Like I know there is a member here with a 3 way using the Heil with a 2251J and an 18 (not sure which 18). He could share his thoughts, cabinet volume, crossover frequency and slope, etc. Someone recently asked on another forum if there was anyone that preferred the midrange of the Scan Speak Revelator 12M4631 or the Seas W14CY001. I told him that sound is obviously subjective, but I much preferred the sound of the paper cone Scan. I shared my crossover info with him along with the other drivers used. Hopefully I was able to save him a bit of time. If I have some info he is looking for, why not share it?

    Od course if in the end I canít get definitive answers then I will indeed build test cabinets and measure, but it would greatly delay my progress. Do you happen to know if two screaming babies would mess up my measurements of the frequency response lol?

    Yes, this Heil was used in a 2 way matching up to a 12Ē woofer and a passive. Most of the designs were 2 ways using a passive, but they did have the Rock Monitors like the Rock Monitor 3 which was a 3 way using a 6Ē mid.

    Do you have any thoughts as to my question on my last response for the sub1500? As far as saving it from glue failure and truly the best cabinet alignment? I have DATS and a WT3, but again, if it can save me a little timeÖ

    Yeah, the MTM idea was just a passing though. Im not sure how the Heil would behave with a cabinet for the mids both on tap and below it, as itís also rear radiating. Plus the center to center spacing on the 10s may not be ideal with the Heil between them. The more I think about it, the side by side may look better. Maybe make the front baffle as it was in the 2SK-3300, mounting the drivers on a slight slant away from each other. Did they do that to eliminate combing and improve horizontal dispersion? My last home speaker design was in a Díappolito configuration using a pair of 5-1/4Ē midwoofers and a 1Ē dome tweeter. So I was just curious if would work here.

    I will keep my eyes open for a JBL drive rack, thank you!


    Appreciate it!
    Dan
    I have no direct experience with that sub driver.

    If you are intending to use massive sub enclosures then you are going to be limited to up to 80 hertz.
    That means you will need a mid bass woofer to fill from 80 hertz up to 300 hertz to this JBL 10 in driver.

    In 2SK-33300 one woofer only did up to mid bass frequencies. The other was driven up to the horn.
    This is because a single woofer of this size was NOT going to cut it in so far as matching the output of the sub in the context of a HT system at 80 hertz.

    This is where l was coming from. Itís simple physics in that a 10Ē driver doesnít have the output to match a serious 15Ē or 18Ē sub crossing over at 80 hertz. If you try it you will hear the problem. But if you use 2 x 10Ē drivers you get a +3dB gain in sensitivity and +3dB in output. Guitar boxes use quad arrays of 10Ē drivers. Go figure.

    The driver motor will run cooler and will have much lower distortion in the bottom octave of it range. You can try a vented enclosure which will give you higher acoustic output around 80-120 hertz.

    I personally would be looking at the driver below in that you will have a much easier design to implement. Your set on using the Heil so itís not a JBL based system anyways.

    Earl Geddes used this driver in his famous loudspeaker designs. In just 85L itís incredible. You wonít find a better driver. Itís smooth up to 2 khertz making it diy friendly and will give you an f3 of 46 hertz in compact enclosure. About the same size as the ESS tower design. They used CTS woofers. The B&C driver is light years better. If you crossover with 24db LR filters the Heil will perform better. I donít think you will have a problem crossing over at 1500 hertz. You can contact Nelson Pass for tips on how to use the Heil. He designed the crossovers and was in R&D at ESS before he struck out on his own. He actually got fired from ESS so the story went over a few glasses of redÖ.Lol.

    https://www.bcspeakers.com/en/produc...ive/15rbx100-8

  8. #23
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    1,405
    Thanks for the 251J data. As i normally do i searched the JBL T/S tables, 2012 and 2021 editions, for the 251J parameters but haven't seen them there, though they should be on the tables driver being released for a while.

  9. #24
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    1,405
    LOL. I stand by my initial impression and guesses about this driver... & I'd take that 2.5KHz upper 3dB spec with a grain of salt, and I've seen no response plots for the 6222:

    "...Also, you wouldn't have to drive the 10" units as hard/low. The Gauss units might work, if they spec out for such duty...might have to drive them separately."

    "Gauss? was thinking of that as the mid-bass element... I have no idea how/if it would match up with the Heil driver on it's own."


    I don't see what's laughable about considering the McCauley 6222 as mid-bass/low-mid driver. Plus its somewhat insulting to the OP owning these drivers, as he wrote: "Iím thinking Iíd like to go with a 10Ē driver. I happen to have exactly 3 McCauley 6222. From what Iíve read this is supposed to be an excellent driver with good midbass" Post 1

    I'm certainly not trying to convince someone who doesn't want to be convinced, don't have time for this, but instead trying to "rehabilitate" drivers that appear to being "trashed". On the practical side having three can be useful, one being a spare in case of accidental overdrive or simply too much ambition.

    initial impression and guesses about this driver are what you have, then a grain of salt about 2.5 khz and the absence of a response plot. Seems pretty thin.

    One doesn't design or build boxes based on guesses and impressions. Need something more serious than this, such as data from a spec sheet. Not trusting the 6222 spec sheet upper response is your privilege but you have no other to offer.

    A number of JBL systems and/or drivers don't show an official response curve and i don't recall you made a big fuss about those.

    As for driving the 10" units as hard/low, that load would also apply to a Gauss, 251J or 6222. Which per se does not differentiate the situation. Looks like a non issue.

    Simply throwing the Gauss name up in the air, with no specifics (e.g. suitable model number) doesn't help the OP moving forward, more so when he didn't seem familiar with Gauss.

    Pic shows the original spec sheet for the Mc Cauley 6222, little better than the internet version (e.g. highest recom crossover). The 6222 is louder than 251 for the same voltage applied (251 being 16 ohms), the 251 is a 60hz driver while the 6222 is a 40hz, didn't see the 251 Pe and Xmax numbers (2251 are 388W, 5.7 mm) compared to 300W and 8.4 mm for the 6222, etc.

    Sorry, but certainly not your most convincing post.

    Name:  IMG_2965.JPG
Views: 218
Size:  219.8 KB

  10. #25
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,696
    Nevermind. Enjoy.

  11. #26
    Senior Member edgewound's Avatar
    Join Date
    Jun 2005
    Location
    Southern California
    Posts
    2,768
    Quote Originally Posted by grumpy View Post
    Nevermind. Enjoy.
    I don't blame you.

    People that don't know Grumpy's background should not question his capabilities.
    Edgewound...JBL Pro Authorized...since 1988
    Upland Loudspeaker Service, Upland, CA

  12. #27
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,696
    No worries. I'm here to learn as much as anyone else.
    Looks like the OP is getting some good info.

  13. #28
    Senior Member
    Join Date
    Apr 2003
    Location
    Australia
    Posts
    7,406
    This is diy and my comments should be taken as such. The difficulty is where a poster wants recommendations because there are as many scenarios that will work as those that probably won’t.

    To reiterate my comments should be taken in the context of meeting / matching the sub at the 80-100 hertz as the per JBL Synthesis dual 10 inch centre l referred to. Not having personally put the 251 in such a design the JBL synthesis is a good example of a real working design.

    There are lots of 6”,8” and 10” pro drivers now days that are expressly spec’s and built for large Array’s used in multiples. In this application they run down toward 100 hertz. In my own experience an 8 inch driver in a 30 litre box tuned to 45 hz with 92db sensitivity is struggling to blend with a JBL 2235H at a crossover point below 130 hertz. This becomes a more taxing problem with modern sub drivers. A 10” driver has more output but it’s still going reach its limit under real conditions in displacement and thermal limited output and problems with power compression. Two 10” drivers or a single 12” driver gives a safety margin. A 15” mid bass has much more safety margin and has more flexibility. They are more efficient, they go louder lower and they are cleaner. You can do that with a single small driver unless your using multiples are asking way way less of it.


    Again this is just diy snd it’s up to the OP where he want to take his project.

  14. #29
    Senior Member RMC's Avatar
    Join Date
    Feb 2017
    Location
    Canada
    Posts
    1,405
    Interesting post 28. Will think out loud here.

    I've kept in mind Todd's 2khz or so for the Heil and Widget's 80hz for woofer (not familiar with) as sort of goals/target. But the Heil response i saw tells me it could do 1700hz or so with steep slope.

    Larger size cone usually good for efficiency, bass, but less for sound dispersion.

    Todd's 10", as well as my 10" (small SR box), have passed the Di 6db point, also passed the Di 10db level, then we're in the "no man's land" already.

    Imagine with a 12" or 15"!!, directivity could become insane for a home box, that's a bugger, unless on a multi-way system. I know large 4350/55 use a 12" but on a limited bandwidth as i recall. I'm not suggesting he should build a large 43xx here.

    Btw the multiplier factor given by Eargle for two closely spaced cones is 1.4, so 10" X 1.4 = 14, therefore two 10" are equivalent to a 14" cone. Still a lot re directivity. I know from checking recently for two 8" on a used JBL system i had in sight (MS 28 i think), the formula gave me equivalent to a 11.2" cone, had hoped a bit more.

    Or the OP uses one 10" but has to moderate the volume control at some point, like in lifting the foot a little on the accelerator pedal. I'm not stuck on the Mc Cauley 6222 (quite practical because OP already has three and i usually try to look at what the member has vs don't have). I noted for an SR 10" its excursion capability at 8.4 mm is generous for driver size (having in mind here Widget's 80hz XO). 2251: 5.7 mm, my SR 10": 5 mm but ok for me.

    My 2 cents. Gotta go.
    Last edited by RMC; 02-02-2022 at 12:28 PM. Reason: corrections plus added phrase

  15. #30
    Senior Member
    Join Date
    Jul 2003
    Location
    Orange County, CA
    Posts
    3,431
    You need to take the "10 inches" with a grain of salt. I just measured the actual radiating area, including the accordion surround, at 8.4 inches for the 2251J. It will not fit in the typical 10" hole without leaving a gap along the "flats".

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Recommendations for JBL speakers (home theater & music)
    By dhatcher in forum Lansing Product General Information
    Replies: 10
    Last Post: 07-28-2008, 08:22 AM
  2. JBL home speakers' drivers table.
    By beppe61 in forum General Audio Discussion
    Replies: 2
    Last Post: 12-05-2006, 12:22 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •