Choosing a Mid-range that Fits. [Archive]

mortron

07-26-2021, 07:00 AM

Hey all, apologies if the wrong sub forum, but am looking to figure out what kind of mids to incorporate into my system. I run active setup with a DBX Driverack 260.

The bass will be a JBL2245, and the HF unit for now is a Celestion CDX1-1745 on a QSC clone guide. Not all JBL, no, but a starting point. I suppose the go to would be to flow the 4345 design principles?

The usual 4345 crossing the 2245 over at 290hz (IIRC) seems to be quite common. My boxes for the 2245 are 8 cubic foot and was considering initially just using them as subs ala the B460. The internet is full of 2 way designs and the like, and folk like Zilch developed the the Econowave, which is very well documented. Choosing a design of finding inspiration for one is tough. Fortunately the HF section is documented elsewhere and isn't totally alien. The 2245 in 8cf is familiar enough, that I am not concerned about how they will perform. It's picking the mid to fill the hole that has be scratching my head.

Assuming I want to keep it as JBL as possible, I have considered a range of drivers from 10-15" including the 2123h, 2251j, 2206h, 2225/6h and so on. It would seem if taking the 2245 to almost 300hz, the 2123h is a wise choice. Using a 1" HF unit now means I need to cross higher than say a 2445. The Celestion can be crossed low enough that a 12 isn't out of the question, and some designs like Pi4's from Parnham cross a 15" to a 1".

The 15" is a lot less appealing with a 2245 in the mix. I don't know if I am looking to clone anything specific at this point. The 2251j is a 10" but usually found in quads and 16ohm. I realize they're not 2123h drop ins, but they are more current 10" offerings and a little more common. I don't think I want an MTM setup. Not sure how hifi folks employ (or if they do) the 2251j.

Sourcing many of these drivers isn't as easy as it was a few years ago even. Naturally the 2206 and 2226 are a little more common finds given their age or lack of. I've considered alternative brands, but that pursuit led me to "we don't have any to send you, but we charged your card" and am getting fed up waiting on bad actors, and have a big hole in my setup.

TL:DR - I am looking for a 10-15" driver to go between a 2245h and 1" driver. Not sure if I go with a higher XO 3 way or like a 2 way with a sub.

Eaulive

07-26-2021, 09:19 AM

If you can put your hand on a set of 2202s, I highly recommend them!
I used 2119 and 2118 in the past and they were also sounding good, although they don't have as extended a range as the 2202 IMHO.

Riley Casey

07-26-2021, 02:31 PM

I listen every day to a pair of 2206's crossed over at 1100 hz into a pair of 2426s on 2344 horns and they sound fine. I use a single 2226 as a sub since the 2206s have no trouble working down to 90 hz. I've tested the same set up with a 2202H that I've had since the 80s and it sounds very slightly better near crossover but I have yet to find a match for it ( and may never ). I've got a pair of single 2226 boxes that I'll use as lows if I ever do find another 2202 and move my crossover from 90 hz up to 250 where I've found the best sounding combination to be. The lightweight, curved cone of the 2202 really does sound better than the heavy, stiff cone of the 2206 ( or any dedicated bass speaker ) as you get closer to 1 kHz but at then any twelve crossing over into a 1" compression driver is to my ears the most pleasant sounding home hifi combination. Much better sounding than the 15" into the same horn / driver combo. B&C makes some nice light coned 12" mid bass drivers if you can't find any old JBLs.

Earl K

07-27-2021, 05:06 PM

@Mortron

A little bit of Reading for you (http://www.audioheritage.org/vbulletin/showthread.php?1859-Is-the-JBL-2206H-ok-for-HIFI)

Follow the other links found within that thread ( for some other opinions ).

:)

toddalin

07-28-2021, 12:05 PM

I use 2251Js with 2241H and Heil AMT.

I run these as a 2.5 way in that the 2251J has no high pass crossover cap but uses its natural roll off from 300 Hz down. When I did put a 30 mF cap in series, it did reduce the low end and volume a bit (which it really needs), but the really critical lowest frequencies only decreased by about 1-2 dB. I guess the impedience peaks in this area and as the impedience goes up, the effectiveness of the cap is essentially lost. Based on that premise, I felt it better to not run a cap and take advantage of the additional volume available as well as the better integration with the 2241. I cross them over to the Heil at ~1,800 Hz. This is just before the 2251s show an major increase in volume and the roll off takes this out.

The 2251s were used in a horn enclosure and very few people have found how to correctly apply them to a home setting. There is a guy located outside of LA who has/had a shiite-load and was selling them on ebay for, IIRC, $130/pr. He even matched the pairs to get the dc resistances the same or at least withn 0.2 ohm. NOW HE SELLS THEM FOR 4/$150 AND STILL HAS A SHIITE LOAD!!! I mean..., come on, $37.50 each!!! That's probably about 10% of JBL retail!

https://www.ebay.com/itm/255061664966?hash=item3b62dc24c6:g:cKYAAOSwpYNg05r u

BTW, if you want 2123Js, there is a beautiful pair in Bakersfield that are/were recently listed on C/L. No affiliation.

https://bakersfield.craigslist.org/ele/d/bakersfield-jbl-2123j-mid-rnnge-drivers/7342516052.html

https://youtu.be/lDSoidjAClo

https://cimg1.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1541x1182/80-screenhunter_313_jul_28_12_20_4142d12fa24f6beee851 c4f41cd01051b3739a73.jpg

Eaulive

07-28-2021, 12:34 PM

B&C makes some nice light coned 12" mid bass drivers if you can't find any old JBLs.

True! Before having the 2202s in my 4520 stack (avatar) I had B&C 12PE32 in them, very pleasing as well and very dynamic for mid-bass.

Mike Caldwell

07-28-2021, 08:04 PM

True! Before having the 2202s in my 4520 stack (avatar) I had B&C 12PE32 in them, very pleasing as well and very dynamic for mid-bass.

I use the B&C 12PE32 in my double 12 mid hi boxes, a very clean dynamic light weight cone mid bass
speaker and very efficient at 101db.

My stage monitors are loaded with JBL 2262 and 2265 speakers.

mortron

07-30-2021, 01:59 PM

Thanks for the replies thus far. Your posts gave me lots to read and think about.

Whilst still torn on which driver would work best, the 2206 was always seeming to stand out as a good choice, and based on what I read since posting this, it would be a safe bet for sure. Looking at the graphs, it looks like I can get away with using them as a 2 way+ sub crossed much lower than a 10" like the 2123/2251.

The 2123J on CL that were posted are super clean! Wow. Good price too but a bit far from my part of Canada. The 2251 guy on eBay's always got the quads, but some look pretty rough and I can't tell if the cones look all stained or what. Also I never realized there was a 2123J, I only knew of the 2251J. It always seemed weird to me a 16ohm woofer used as a single but I guess it doesn't matter if I'm running active and have the power for it. They are super well priced tho! I keep trying to avoid buying stuff I don't necessarily need at the time, as I have been a sucker for a good deal many times. Can only hoard so much heh.

I was tempted by a pair of 2262 not long ago, and they were fairly priced I think. I was apprehensive for some reason, thinking the 2206 would be better suited for some reason. Another post I saw mentioned it's very similar tech to the 2216's coil. Differential drive?

In the linked thread... The two graphs EarlK overlaid were pretty impressive, and the 2206 looks smoother, but he also mentioned it could be the smoothing applied that explains the difference. I found it interesting the response above 2khz to 3khz looks very similar in the shape, but ones a bit smoother... I presume the response in this range is what a 12" does in that frequency band? Not that I want to take it that far, just that I noticed the similarity in the shape of the peaks up there. Breakup I guess is the term?

I saw someone using a 2206 crossed about 800hz and found 1000hz to be better for their system. Would it be safe to assume I could cross to a compression driver around 1200hz? There was a question about the flatness to 2khz and whether it was legitimate. I presume it would be the case, and that crossing a little higher than 1000hz is not impossible?

B&C... I read lots of good stuff from them. I dunno if I would buy them locally and shipping woofers may get expensive.

2206 vs 2262 is what it seems like it should be between for me. Comparatively it would seem they both have lots going for them, and no one a clear runaway. Do I go with the ferrite magnets and the classic? Or do I go with newer tech and a neo magnet? Is it a matter of whatever is available? Whatever is cheapest? The prices for bread and milk are hard enough to keep track of these days, I have no clue what either of these drivers should be selling for.

Riley Casey

07-30-2021, 05:09 PM

Many of the benefits of Neodymium over ferrite as magnet material are superfluous in finding drivers for home hi-fi use rather than portable PA applications. When the price and availability of Neo changed abruptly ( most comes from China ) JBL quickly limited the drivers they used it in to those speakers where it was absolutely essential - touring pro audio systems that wouldn't work with the added weight and size of ferrite. Many current JBL pro speakers that were once Neo magnets now use ferrite for similar models. Your posts seem to make most of this is fairly academic if you're not trying to recreate the original classic JBL studio monitors but are instead aiming for more of a general idea of the 4355 speakers or what ever model you decide to emulate. If so buy what gets you the sound you want at the price you're willing to pay. Modern high power amps and DSP will paper over an awful lot of differences in final design choices.

Thanks for the replies thus far. Your posts gave me lots to read and think about.

...

2206 vs 2262 is what it seems like it should be between for me. Comparatively it would seem they both have lots going for them, and no one a clear runaway. Do I go with the ferrite magnets and the classic? Or do I go with newer tech and a neo magnet? Is it a matter of whatever is available? Whatever is cheapest? The prices for bread and milk are hard enough to keep track of these days, I have no clue what either of these drivers should be selling for.

mortron

08-07-2021, 05:42 AM

Riley Casey

08-07-2021, 10:05 AM

The 8" mid drivers should fill nicely between 2226 woofers and 1" compression high drivers and allow you to move the crossover point for mid to high up to 1500 hz or so making the high driver much happier. In the 4889 Vertec systems the crossover frequency between the 15s and the 8s was 250 hz but with only one in each cabinet you could easily go to 500 hz for better performance from the 8".

Thanks everyone.

I was considering a pair of 2262 for a bit, but a pair of 2251j came into my life due to good karma or something bigger, so they will be my mids for the time being. ....

toddalin

08-07-2021, 11:08 AM

Thanks everyone.

I was considering a pair of 2262 for a bit, but a pair of 2251j came into my life due to good karma or something bigger, so they will be my mids for the time being. Obviously going to be crossing over higher than 80hz, and figure the 4345 crossover points will be sufficient for my bass to mid handoff. It makes me think my current compression driver will not live up to the rest of the drivers heh.

I guess now I need to see what kinds of success folk have had using the 2251j in a 4345 type setup. My waveguide is the B52 "clone" of the QSC waveguide that some will know of and Celestion CDX1-1745 I have a few here. Not sure if I will stick with them or go full JBL. The idea of a PT guide and JBL compression driver just sounds like it makes sense. I will play with what I have for now. Baby steps.

Don't cross the 2251J over lower than ~300 hz or run them as a 3.5 way. JBL did put it in one of their big 4-way monitors and IIRC use ~290Hz.

Above ~2K the 2251 will experience a rise in volume so I cross them over just below this.

Yes, 1,200-1,500 Hz will work well with the 2421.

https://cimg1.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1541x1182/80-screenhunter_313_jul_28_12_20_4142d12fa24f6beee851 c4f41cd01051b3739a73.jpg

https://youtu.be/lDSoidjAClo

mortron

08-07-2021, 06:02 PM

Your video sounded good so I was happy to find out I could get a pair. I have a Driverack 260 I use currently, but would like to migrate back to passive biamped if at all possible, as I feel it would sound better than using the Driverack. I also have an Ashly XR2000 I like, but when I tried the Driverack, it was clear the Ashly needs some maintenance. Having the Drivers k is huge tho, and don't want to down play it's utility. Until a HF unit is fully determined, I will be keeping it fully active with the Driverack.

What is the volume of your bass cabinets? I like your setup, as it looks a bit more modern. Am torn between the 4345 type aesthetic and a more modern look like yours. Reminds me of GTs setup too.

toddalin

08-07-2021, 08:17 PM

~6 to 6.5 cu ft interior. Bigger would be better.

mortron

08-09-2021, 07:16 AM

I have cabs that are 8cubic ft per so I should be good to start there. I have enough components to get started, and the bass/mid integration will be my starting point as I've not committed to a HF driver, just hoping what I have on hand is going to work, as the drivers were dropped by someone and they were only 2 left. I need to test them still. May have a backup if need be.

I like the idea now of the 10" and not needing a compression driver that goes too low. Some other posters on forums have said good things of the 2407/2408 HF drivers and have always been kind of curious about them and what other 1" drivers would fit above a 10 well with good HF extension. I'd like to keep it all JBL but not necessarily if it means that it will be detrimental. Im okay with breaking from brand loyalty if there's enough value.

Toddalin, do you use your LPads often on your speakers?

toddalin

08-09-2021, 11:32 AM

Toddalin, do you use your LPads often on your speakers?

Yes and no. Yes, to turn off a speaker for testing the others. No, because all of the values in the crossovers are geared for all of the drivers to run at "full tilt boogy." When you turn the L-pad up all of the way, it is essentually removed from the circuit except for the contact point which is how I run them.

I will typically engage the UHF switch unless the recording has lots of HF hash, in which case I will turn it off.

mortron

08-11-2021, 06:17 AM

Thanks for the replies.

As it stands, I need to make some cabinets to house the 2251J and am curious the volume you settled on. I see the JBL enclosure guide lists a 1.5cft enclosure for E120 midrange, but that sounds a bit large, especially given the 2251J doesn't need to be in an 80hz tuned enclosure. I suppose using the volume of the 4345 midrange cone would be closer to what I am needing?

toddalin

08-11-2021, 10:44 AM

I simply used an 8" wide x 3/4" thick "shelf" board and made a ~11.5" x 11.5" x ~8" deep box adding a face and back from (IIRC) MDF. I also have a rear port made from a PVC coupler, reemed out a bit, and lined the inside of the backs with felt cloth.

http://www.audioheritage.org/photopost/data//500/medium/DSC_00574.JPG
http://www.audioheritage.org/photopost/data//500/medium/DSC_0055_2_.JPG
http://www.audioheritage.org/photopost/data//500/medium/DSC_00583.JPG
http://www.audioheritage.org/photopost/data//500/medium/DSC_00058.JPG

mortron

08-11-2021, 09:13 PM

Hi mortron,

Somewhat late to the party, but this might help you.

The Enclosure Guide's 1.5 CF, Fb 80hz, is good for E120 as woofer in a two-way system for example (read the note at bottom of page 1 of Enclosure Guide, the E120 is not mentioned there, indirectly confirming my statement).

As i understand it (since i'm late), your driver application would be to use E120 for low-mid. Checking the TS for the driver, Qts is very low at 0.17 which helps in reducing box size to house the driver.

In such application driver is usually housed in a small closed sub-chamber. But the best way to know for sure which size box is to model the driver in speaker design software.

According to Eargle's Loudspeaker Handbook the upper limit for a 12" is 875hz @ DI 6 db, and somewhat stretched is 1313 hz @ DI 10 db. So more directional (this being a musical instrument driver it most probably has a rising response that you may benefit from, with the inconvenience of having more directivity).You decide if proper

Driver EBP is 315 in principle driver more suitable for horn, but not necessarily a no here. Regarding the Graphs:

First assuming 2 Pi box placement, then second one with baffle diffraction loss (no 2Pi), somewhat better for low-mid (you're actual result may be somewhere in between)

Standard QL 7, this can be increased to QL 10 due to small box size, if well made, higher QL means little smaller box can be used because of reduced losses, but at some point need to have enough volume to fit the driver in.

1 or 1.5 cf response graphs i get from modeling are practically the same.

At first sight, 1 cf sub-box seems feasible as per dimensions given to me by Winspeakerz software, with a little "cheating"/adjustments (H vs W vs D).

I'll post my graphs and sub-box dimensions later tonight, gotta go now...

Richard

Richard,

Thank you for such a thought out reply. I am not using an E120... apologies if there was confusion. I simply mentioned it as it was the smallest enclosure on the list and E120 would alloy one to find it in the list... Apologies. Or am I mistaken and your math is for a 10" like the 2251J? Regardless I feel I've learned something and appreciate it.

Toddalllin, thanks for your pics. You mentioned a read port. Is a port essential to using the 2251j down to around 300hz??

toddalin

08-13-2021, 12:34 PM

Richard,

Thank you for such a thought out reply. I am not using an E120... apologies if there was confusion. I simply mentioned it as it was the smallest enclosure on the list and E120 would alloy one to find it in the list... Apologies. Or am I mistaken and your math is for a 10" like the 2251J? Regardless I feel I've learned something and appreciate it.

Toddalllin, thanks for your pics. You mentioned a read port. Is a port essential to using the 2251j down to around 300hz??

Probably not. But I ran them open back, closed back, and with the port and preferred the sound with the port best. Recognze that Wilson "vents" their smaller drivers too.

Because of the fins on the heatsink, it is necessary to mount the speakers the same way in both cabinets (i.e., the leads won't look symmetrical).

mortron

08-14-2021, 12:07 AM

toddalin

08-14-2021, 10:54 AM

I will have to take a look at them, but I presume you mean because the fins should run vertical?

In regards to the different enclosure types used, how would you compare/contrast the closed, open and ported designs? Also, did you use the same enclosure for all those alignments?

Yes, because the fins can either let the air flow through them on its way to the port, or the air has to flow around them on its way. The fins create "channels".

Yes same cabinets. The open back was lacking "body" and there seems to be a touch more "openness" with the port open rather than closed.

mortron

08-21-2021, 05:32 AM

Is there any benefits to a larger enclosure for the 2251J in your post Toddalin? Or is it just wasted space?

toddalin

08-21-2021, 12:10 PM

Probably wasted space to go much larger. But I do feel a substantial amount of air moving through the port on the rear at lifelike volume levels (1.65" ID x 2.5" long).

Really captures a Strat the way it is supposed to sound. The L200/300 just don't get it.

https://youtu.be/U1i58tiF6Zo

Mr. Widget

08-26-2021, 03:06 PM

Really captures a Strat the way it is supposed to sound. The L200/300 just don't get it.
Hi Todd,

You and I have disagreed in the past on the usefulness of YouTube videos, but the one you posted here is quite useful. Not so much for the sound quality of your room, but rather to better understand the system requirements an individual might have. Had you posted the name of the artist and of the song being played I would have missed your meaning completely. I don't listen to music like this, Voodoo Child by Stevie Ray Vaughan, (had to use Schazam for that info) and so never would have understood where you were coming from.

I prefer a speaker with a more laid back sound that is capable of capturing texture, micro dynamics, stage depth and width etc. My personal speakers which please me completely would likely disappoint you playing this type of music. A high sensitivity system with a more forward sound (we used to call it a presence peak) is going to make this type of music sound much more immediate and "real".

I'd submit this partially explains how someone can say that speaker A is crap and speaker B is pure music, when another listener might have the opposite opinion. The same is likely true regarding electronics and other aspects of this hobby. I'm sure this is self-evident to many of you, but once again I'm late to the party.

Widget

Mr. Widget

08-26-2021, 06:52 PM

toddalin

08-26-2021, 09:12 PM

As a postscript, I gave the 1968 Jimi Hendrix version of Voodoo Chile a spin. Damn! That is a magnificent living breathing recording with air, space, depth… Stevie Ray Vaughan’s 1984 recording is squashed and lifeless.

In general I am not a rock guitar fan… prefer the jazzier guitar style of folks like Mark Knopfler, but Jimi Hendrix was beyond gifted.

Widget

I think I have the JH version on CD. I'll have to record that for comparison.

A Strat though a Cry Baby should sound like a Strat through a Cry Baby (and usually Marshall) and they have a definite signiture and are not "laid back." They are supposed to be "in your face."

toddalin

08-26-2021, 09:32 PM

One can go on YouTube and find a direct recording of the track and compare it to that made of someone's system to hear the fidelity the system to the original as well as the effects of the room. My room is actually quite lively.

https://youtu.be/sF2ZqlPNuqU

I think mine hold up quite well and you can hear how nice and sharp the transients are.

Mr. Widget

08-26-2021, 10:50 PM

A Strat though a Cry Baby should sound like a Strat through a Cry Baby (and usually Marshall) and they have a definite signiture and are not "laid back." They are supposed to be "in your face."Perhaps, but in my opinion, raspy and screeching alone does not make it great.

One can go on YouTube and find a direct recording of the track...I guess I should have been more clear. I played back a few seconds of your YouTube video on my laptop and used Shazam to discover what I was listening to. I then went downstairs and played back a 176.4kHz 24bit file of the record through my system... for the Jimi Hendrix version, the best I had available was Red Book CD. It didn't matter, even in hi rez, the Stevie Ray Vaughan track sounded lifeless.

I think I have the JH version on CD. I'll have to record that for comparison.
Don't record it. Play it. Listen to it. And enjoy it! It is phenomenal.

And it too is pretty much "in your face". Please give it a good listen. Then tell me if you don't agree that Mr. Vaughan's version lacks something.

To the OP, I apologize for the distraction.

Widget

Eaulive

08-28-2021, 08:40 AM

I'd submit this partially explains how someone can say that speaker A is crap and speaker B is pure music, when another listener might have the opposite opinion. The same is likely true regarding electronics and other aspects of this hobby. I'm sure this is self-evident to many of you, but once again I'm late to the party.

Widget

I think this is mostly due to coloration and inexperienced listeners who look for a specific effect, like boomy bass or punchy bass or forward midrange. I think the perfect speaker should be able to play any kind of music flawlessly and make it enjoyable. Of course it will also expose the flaws of the recordings that might have been masked by a lesser setup thus making that setup sound better.

But at the end it's a personal choice, and a setup you might have liked 10 years ago can be dissapointing in the present day.

Eaulive

08-28-2021, 04:37 PM

toddalin

08-28-2021, 06:31 PM

By the way, I listened to both versions, the original "Voodoo Child (Slight Return)" from the 1968 "Electric Ladyland" album and the SRV version from the 1984 "Couldn't Stand the Weather" album.
The SRV version is cleaner, more adapted to plain vanilla audiences and casual listening with a much tamed guitar sound, the JH version is totally crazy, with flanging and L/R panning throughout, the guitar is more dirty, more in your face.

I like both, but JH gets my vote.

My apologies to the OP as well, this is a bonafide thread hijack :D

And I just finished listening to the JH version. My SRV disk is SACD. It is cleaner (revealing a cleaner recording), the transients are much "snappier," and the soundstage and imaging are better. JH Strat is more laid back than SRVs, but that could be the difference in the recording process/chain. I actually prefer the SRV version. JH gets a bit carried away.

Earl K

08-29-2021, 06:56 AM

toddalin

08-29-2021, 11:45 AM

Interesting.

Note that in this application, the 2251J is the smoothest.http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=89457&d=1630248290
http://www.audioheritage.org/vbulletin/showthread.php?42348-Refining-the-Old-Girl

What the graphs don't show is performance beyond frequency response. While the 2251J is a bit less sensitive, it will handle the most power in compensation (400 watt rating). It also uses a differential drive system that in theory/literature should produce the best transient response and lowest distortion.

Then when you look at the outrageously LOW price for 2251Js, it becomes a no brainer. This is the same guy I got my set from so many years ago, and he still has a boatload to get rid of. His prices have actually dropped by about half of what I paid (IIRC $130/pr), but his shipping has gone up. (though he only shipped two pieces to me and is shipping four pieces here). If you don't like the set shown, he has others.

https://www.ebay.com/itm/255097366660?hash=item3b64fce884:g:850AAOSww09g05c 6 (https://www.ebay.com/itm/255097366660?hash=item3b64fce884:g:850AAOSww09g05c 6)

In actuality, the 2251J is a bit low in sensitivity compared to the 2241H, and a pair used in MTM fashion could be just the ticket. Remember that the 2251J was designed to be horn-loaded and all of its JBL published sensitivity ratings are based on it being horn-mounted. I put a resistor in parallel with the 2241H to reduce its sensitivity, but crossover-frequency wise, it would be better not to have the resistor. A second 2251 could take care of this and probably reinforce its low end a bit more. And at those prices, one could certainly afford to do so. Mine have worked as new and still do.

RMC

08-30-2021, 02:19 PM

Todd,

RE "I put a resistor in parallel with the 2241H to reduce its sensitivity," (post # 34)

What type, power rating and resistor value do you use for that purpose? Any inconveniences noted on driver performance/sound? Thanks.

toddalin

08-30-2021, 04:01 PM

I use a 50 watt Dale resistor (~20-30 ohms but currently ~27 ohms). 20 ohms seems a bit too little for the 2241 (makes it a bit bass light) and 30 ohms is a bit too much (a bit bass heavy).

But this would not be necessary if using a 2245 because it is not as loud/efficient as a 2241 and should be just about perfect. Also note that I don't run a high pass cap on the 2251J. (I actually run these as a 2.5 way.) I found that it just reduces the volume a bit and really does nothing to change the slope or attenuate the very low bass (maybe 2 dB). And why put the signal through more components if unnecessary?

This would be interesting to model.

https://cimg1.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1541x1182/80-screenhunter_313_jul_28_12_20_4142d12fa24f6beee851 c4f41cd01051b3739a73.jpg

RMC

08-31-2021, 12:46 AM

Todd,

Thanks for the reply. Not drawing any conclusions about resistor on woofer, just curious that i may be missing something or not. You're the second member i see recently using a resistor on woofer, not usual, however the other fellow used his in series. I've used occasionally low value resistor in series with mids and tweeters but never on woofer, series or parallel. Hence my curiosity.

One case i did was a small 4 parallel speakers system driven by a small receiver in a small room. Not really enough juice for series connections, also couldn't cope with the less than 4 ohms of the 4 boxes in parallel. One pair acting as rear channels having lower impedance than the other but also higher sensitivity. So that one got a series resistor increasing its impedance and by the same token reducing its sensitivity. This after some calculations and resistors testing. The outcome is good, levels are where i want them, receiver never complained about load seen.

In your case since its to reduce sensitivity also any particular reason why not a smaller value resistor but in series instead of higher value in parallel? Power capacity, damping factor, back EMF, whatever?

Btw, you mentioned previously here about box size for the 2251J. With its pretty low Vas and Qts numbers no wonder you were able to use such small box. EBP 277 nice for horn loading too (HLA 4895).

RE And why put the signal through more components if unnecessary?

I can't disagree with that. I've mentioned before i'm of the opinion that when a driver in a system needs a whole lot of adjustments or corrections in the crossover, then it may be the wrong driver to begin with... therefore look elsewhere for a more natural performer in view of application.

toddalin

08-31-2021, 10:36 AM

A low value resistor in series with the woofer is sometimes done and people equate this with a "tube" sound (BTDT). But it has an impact on how the woofer responds in that it hurts the damping, which is why it is often equated with tube sound. Tube amps typically have a relatively low damping factor compared to solid state.

BTW, if you look at JBL crossover schematics, you will find that dozens use/used a resistor in parallel with the woofer, whereas I can't remember any where it is placed in series. Whether it be to reduce the volume to the woofer or modify the crossover slope, I guess would depend on the selected drivers, their efficiency, their characteristics, and the preferred slopes.

I have an A/B/X switch box, and too match two sets of speakers, I can attenuate the signal at the line level, at the speaker level (using 100-watt L-pads), neither, or both. When I use the L-pads, the bass is notably "mushier" most probably because the difference in damping.

RMC

08-31-2021, 11:50 PM

Todd,

Thanks for the interesting explanation.

I design mostly around a woofer i want to use, not always though, and choose the other driver(s) accordingly. Since i never had to pad a woofer never did, plus in my head its kind of against nature. So I find a work around or use another driver.

For a mid that has little lower sensitivity than ideal, or a small dip in response, this isn't a major problem considering the Fletcher Munson equal loudness contour curve. The ear is already more sensitive to mid frequencies than to others, so upon listening the subjective impression isn't much compromised.

This goes along your: "why put the signal through more components if unnecessary?"

mortron

09-02-2021, 06:08 PM

@mortron,

Here's a comparison of JBL's 3, main 10" mid-rangers most commonly used in projects.

These are traces made from JBL's official EDS documents ( found in the Transducer section of this very website ).

89452

To these eyes, the 2123h is the smoothest within the usual ( useful ) passband area of 200hz - 2Khz ( followed by the 2251j and then the 2122h ) .

Conveniently enough ( for the project designer ) all 3 perform very well with the ( Giskard modified ) 4344/4345 network ( the 8 ohm variable Lpad has the effect of moderating the impedance differences ) .

Here's an Xsim prediction for these same 3 midrangers filtered with the 4345 midrange filter ( balanced//adjusted for output using the variable Lpad of that filter )

89457

I had to use "traced" impedance files ( which is only so good since they weren't made with these drivers located in the stock .5 cu' enclosures > which shifts the impedance peak upwards ).

:)

EarlK, Thank you for this post, I feel it answered a few questions I didn't know I had. I presume the L-Pad is what helps match the 8ohm drivers to the 16ohm driver? I must admit to being a bit naive about L-Pads. I will do some googling. As for the crossover in the Giskard Network, is that the filter to pursue if one of us are looking at a 2245/2251 pairing?

----

Toddalin, in your use of the 2251J, had you tried it on a wider baffle? If so, how would you compare them? Am still wrestling with a setup like yours or a large baffle speaker. If you did it over again, would you still go same route?

Earl K

09-03-2021, 06:34 AM

EarlK, Thank you for this post, I feel it answered a few questions I didn't know I had. I presume the L-Pad is what helps match the 8ohm drivers to the 16ohm driver? I must admit to being a bit naive about L-Pads. I will do some googling. As for the crossover in the Giskard Network, is that the filter to pursue if one of us are looking at a 2245/2251 pairing?

You can use that N3145 filter ( for the 2245 and 2251j ) as long as the 18" and 10" are tight packed ( iow; closely oriented to each other like in the 4345 ) .

If your intention is to build a two box system, then going the route that Todd went makes more sense ( the port in a slightly larger box > such as .75cu' - 1cu' < tuned high > such as maybe 120 hz > should be able to give a bit more usable LF to the response of the 2251j ). This might allow a lower crossover point ( which becomes an advantage as you move the two boxes further and further apart )

Play around with some different tunings ( with various box sizes ) within winISD until you find a reasonable LF response for the 2251j.

Post your results here.

:)

mortron

09-05-2021, 07:35 AM

You can use that N3145 filter ( for the 2245 and 2251j ) as long as the 18" and 10" are tight packed ( iow; closely oriented to each other like in the 4345 ) .

If your intention is to build a two box system, then going the route that Todd went makes more sense ( the port in a slightly larger box > such as .75cu' - 1cu' < tuned high > such as maybe 120 hz > should be able to give a bit more usable LF to the response of the 2251j ). This might allow a lower crossover point ( which becomes an advantage as you move the two boxes further and further apart )

Play around with some different tunings ( with various box sizes ) within winISD until you find a reasonable LF response for the 2251j.

Post your results here.

:)

Imma do that for sure.... As soon as I hook my desktop back up (painted the 'office' recently) as my Dual Core Celeron Laptop with 4gb of ram, has enough trouble with loading a webpage... Or Windows login screen... That Winisd is probably even too much for it to manage. Windows 10 is like the loudness wars for computers. How big of a boat anchor can they make??? :blink:

I'm guessing the smoothness of response would be affected by transitions in the two different box sizes and those would need to be measured, or can it also be simmed in another program?

toddalin

09-05-2021, 12:06 PM

This is why I run them as a 2.5 way. Look at that nice low end roll off. There is also an impedience peak at the very low end. When a cap is used in series with the 2251, it does little to protect the driver down in this range because the impedience is so high. The higher the impedience, the less effective the cap. My cabinet may be a bit small because I have a bit more low end roll off than shown, but that probably provides more protection for the 2251. But it could just as easily be the room because the 2241 also shows a substantial dip ~200 Hz.

https://lh3.googleusercontent.com/proxy/iuKY1XRCCQtMmB2IfYHGNxeCa2c-QXzGhRZbXRd9E1DPpCzA6Z1kJTfYDkSFb7NlCgDoC-l49K7EdjQ0ST7kf3qJt3QnLOh9iqMtBVkW8ScPG4aK3jlZuEgO B2hg5lecXiyGV8g07Ma5p-IyUYhCRq9RNw

mortron

09-28-2021, 04:05 AM

Sorry folks... Got called away for an inspection gig... Not ignoring the wicked contributions from y'all. Be back soon!

toddalin

09-28-2021, 11:15 AM

I decided that I was loosing a bit too much in the ~200-300 Hz range, so I changed the parallel resistor on the 18" from 26.8 to 36.8 ohms, changed the inductor from 8 to 5 mH, and reduced its cap from 89 to 59 mfd. This lets the 18" play a bit higher into this range adding about 2 dB in the depression. The resistor reduces the overall volume from the 2241 by ~1 dB. Without the resistor, the bass is a bit overpowering reducing intelligibility.

Ian Mackenzie

10-04-2021, 03:41 AM

Hi Morton?

This is a wild card idea.

Years ago in a local club they had a particular good system build as a permanent installation.

They used three 2225 drivers back then, 4 x K110 and a 2497 with dual drivers.

The system was very smooth and had good linearity for life bands a d disco.

You could scale the approach to your domestic situation with the 2123 or the 2251.

Those 2226 woofers are going to be close to 99 dB if closely coupled and make use of a 4 ohm load on a suitable amplifier. So the notion of 2 x 2251 or the 2123 could deliver high sensitivity and very low distortion with a nice relatively small separate amplifier for the mid and top end.

If you chose the 4351 orientation this would allow latitude for a multi way composite driver baffle snd more flexibility in enclosure placement.

Typically the 4350 needs a back wall of 4 metres to enable sufficient spacing of the mid and horn while keeping the outer woofer a modest distance from the side walls. 6 or 7 metres is preferred to avoid side wall interference.

So you might find the 4351 type of enclosure orientation easier to work with. One woofer near the floor with provide some boundary reinforcement while the upper woofer will be led effected in the upper bass. Similarly the 10 inch driver array will be well clear of wall boundaries as the enclosure could be oriented for the mid and horn inside or outside looking at the baffle layout.

Something to think about.

toddalin

10-13-2021, 06:02 PM

OK! I made some revisions to the crossovers on the Mermans and have produced the best version to date.

https://cimg7.ibsrv.net/gimg/www.corvetteforum.com-vbulletin/1550x1157/80-screenhunter_354_oct_13_13_51_2bdffa27b97a403c413a b0779802e8b5e15a302c.jpg

As always, this is just a CD played on the Oppo 95 through the Yamaha RX-Z9 receiver set to CD direct. There is no sub, digital processing, eq, or electronic room correction or acoustic room treatment involved. The room is fairly large (26 x 16.5 x 7.5 --->16' ceiling), open in one corner to the entry hall and the dining area. You are hearing just the two inner speakers recorded on a Nikon D750 digital camera.

https://www.youtube.com/watch?v=T6KV_qRyA7g