Holy Grail of Subwoofers: A Pair of 2245's

[Champster]

I have completed the construction of a pair of 2245 18" subwoofers to compliment my Linkwitz Labs LX521's. This is a active 5 way system using a MiniDSP 4x10hd and two ATI 1506 amps. Each driver in the whole system has it's own 150W amp with the subs working from 35hz down. I borrowed the design from Greg Timbers 1983 design. (http://www.lansingheritage.org/html/jbl/reference/technical/1983-subs.htm) I have slightly curved sides but otherwise there is no deviation from their design. These are amazing at what I ask them to do. I have them equalized +10db at 17z. These blend fabulously with the pair of open baffle 10" drivers in the LX521's, which is no easy task. For those of you that haven't heard open baffle woofers, you're missing half of life. These are an fantastic addition to the LX521's for any kind of program material with sub 35hz signal. The 10" woofers below about 35hz have dramatic cone excursion which is fine, but to me it sounds as if they are struggling to reproduce these frequencies. The JBL's on the other hand are smooth and very comfortable keeping up with the main system.66520665236652566526

[4313B]

Outstanding! :yes:

I really like that light veneer.

[grumpy]

Nice job!

[Mr. Widget]

Not compact, but they look good in your room. Congratulations!

Those 2245s probably are one of the best solutions to mate with open baffle designs. I must add that I have not yet heard an open baffle speaker that worked for me including hearing demos by Siegfried Linkwitz, but then he wasn't using B460s. ;)


Widget

[RedCoat23]

Really superb craftsmanship sir. I tip my hat to you! :applaud:

I've never had a chance to hear any open baffle speakers other than electrostatics - different kettle of fish I know. I need to get around to it at some point.

[Champster]

Thanks guys! I have to really thank Lee in Montreal (http://www.audioheritage.org/vbulletin/member.php?14324-Lee-in-Montreal) for his suggestion to go with the 18" vs the 15" 2235's. I've had many subs over the years, but the largest (previously) was a pair of 15" Velodyne ULD15. They are wonderful but the 18" is really in a different league, especially when you push them hard with organ music or movie soundtracks and I'm not just talking dinosaur footsteps. But even when you don't push them hard, they provide a room "feeling" that smaller speakers just can't. Even my Infinity Beta's (4 x 12") didn't do it. Now I've got a real problem. I'll never be able to move to a smaller room cuz these things are huge!

[Champster]

Not compact, but they look good in your room. Congratulations!

Those 2245s probably are one of the best solutions to mate with open baffle designs. I must add that I have not yet heard an open baffle speaker that worked for me including hearing demos by Siegfried Linkwitz, but then he wasn't using B460s. ;)

Widget

I'm impressed you've even heard of Linkwitz speakers. When I walk into High End stores and they ask me what I'm listening to I think I've only had one guy vaguely know what they were but had never heard them. Which model did you listen to and where? SL is very generous with his time to let people come over and listen. I know what you mean about them not working for you. Isn't it great there are so many different speakers made so we can all have what we like.

[Lee in Montreal]

Very nice work. Those are high voliume, though they don't look that cumbersome. Thanks to th tower design. Just tell your sweet half not to put flower pots on them... ;-) One comment I'd like toadd is about the benefits of curved sides. Not only they make the cabinet look smaller, but the curve strengthens the panels and keeps them from resonating as there is a tension in the boards. And a curve is always stiffer than a flat plan.

And yes, the physical feel of those 2245 is incredible. ;-)

[Mr. Widget]

I'm impressed you've even heard of Linkwitz speakers. When I walk into High End stores and they ask me what I'm listening to I think I've only had one guy vaguely know what they were but had never heard them. Which model did you listen to and where? SL is very generous with his time to let people come over and listen. I know what you mean about them not working for you. Isn't it great there are so many different speakers made so we can all have what we like.Sorry... just saw this. I am not sure which ones they were. They were much smaller than yours. It was a few years ago at a DIY audiofest in Marin County. The event is called "Burning Amp". Nelson Pass and other notables were also there. Dr. Linkwitz lives nearby and is a very generous and gracious fellow who will talk about his theories and designs to almost anyone if asked politely.

I agree on the variety point 100%. I find most speakers with a following do indeed offer something to be admired even if they don't entirely float my boat.


Widget

[Don C]

Further OT, But...

I don't know the man, and haven't heard his speakers, though I'd like to. But I certainly have a lot of respect for him, because I spent a lot of time using the instruments that he worked on at HP. Anyone who worked on the 8566 is OK in my book. That thing was awesome.

66596

[grumpy]

lol... yes, those were much nicer than what I started on ...
killed a lot of plotter pens :)

[Ed Zeppeli]

Nice design and construction Champster!

Do you have any pictures of your build?

[Champster]

Nice design and construction Champster!

Do you have any pictures of your build?

Thanks Ed. I'm afraid I only have one picture and it isn't great but its all I have. I painted the interior with an automotive sound deadening material and then put the 2" Auralex foam over all the surfaces. The curved sides are 4 layers of 1/4" mdf laminated and there is extensive bracing. These weigh about 250 lbs each. The front and rear baffles are 2" thick mdf. When really rocking these cabinets are nearly vibration free.

Paul

66603

[chrapladm]

Hello. I dont believe you stated this but what size cabinet did you go with? 8cuft 25hz or 12cuft 20hz?

I am guessing 12cuft 20hz. Just curious as I am very slowly gathering parts for a possible clone 4345 and possibly other builds.

[Champster]

Hello. I dont believe you stated this but what size cabinet did you go with? 8cuft 25hz or 12cuft 20hz?

I am guessing 12cuft 20hz. Just curious as I am very slowly gathering parts for a possible clone 4345 and possibly other builds.

8cf

[chrapladm]

So 8cuft per plans?

I only ask because looking at your picture above it looks like a large port but not sure what length you went in the end.

[Champster]

So 8cuft per plans?

I only ask because looking at your picture above it looks like a large port but not sure what length you went in the end.

Yep, it is exactly as taken from the drawings of the Greg Timbers 1983 design. No deviations other than cabinet shape. My port is 6" in diameter (Madisound sourced) with the curved end pieces. It's 12" long, but that is getting kinda personal...

[chrapladm]

Ah ok thanks. If you did not want to reveal specifics that would have been fine also. I was just curious where the port was going from the picture. At first I thought i was looking at a dual opposed design but then realized thats definitely not whats going on :D

[Champster]

Naw no secrets here, as I said, this follows the design so I didn't figure repeating what is on the drawing would be relevant. Here are some other pics of the port. It is directly behind the driver with a 6" gap between the rear of the driver and the front of the port.
670366703767038

[chrapladm]

Thanks again for the added pictures.:)

[cosmos]

Champster, your build looks absolutely beautiful! Great job.

However, I am wondering if the 10" OB would perform better if you allowed the 2245 to provide everything from say 60 or 70 Hz down, rather than tasking them to go down to 35 Hz. I am thinking that the extra excursion required has to have some negative effect on higher frequencies. Since you are using active crossovers, I would suggest playing around with raising the crossover frequency.

Currently, in one of my systems, I am running a solo 2245 in a 12 cu ft box crossed at 75 Hz to a pair of E145 (15") providing woofer and midbass duty, something they excel at. Prior to that, this same system was running a pair of 2245s in 16 cu ft boxes on each side.. This seemed to be overkill and took up so much space.. Pic below was the day I assembled the system, first trying it outdoors to free up room issues before moving it indoors.

My personal experience with this driver indicates it works very well to 100 and maybe even up to 140 Hz. In your application, I surely would try lessening the burden on the 10" and raising some..

If you do try raising the crossover frequency, PLEASE let us know your thoughts.

Further, I think I will try building some boxes similar to yours, probably in 12 cu Ft, but with curved sides like yours. I am very impressed with your build and application and would love to hear your system!! Kuddos!!:applaud:

Dan

67198

[Champster]

Champster, your build looks absolutely beautiful! Great job.

However, I am wondering if the 10" OB would perform better if you allowed the 2245 to provide everything from say 60 or 70 Hz down, rather than tasking them to go down to 35 Hz. I am thinking that the extra excursion required has to have some negative effect on higher frequencies. Since you are using active crossovers, I would suggest playing around with raising the crossover frequency.

Currently, in one of my systems, I am running a solo 2245 in a 12 cu ft box crossed at 75 Hz to a pair of E145 (15") providing woofer and midbass duty, something they excel at. Prior to that, this same system was running a pair of 2245s in 16 cu ft boxes on each side.. This seemed to be overkill and took up so much space.. Pic below was the day I assembled the system, first trying it outdoors to free up room issues before moving it indoors.

My personal experience with this driver indicates it works very well to 100 and maybe even up to 140 Hz. In your application, I surely would try lessening the burden on the 10" and raising some..

If you do try raising the crossover frequency, PLEASE let us know your thoughts.

Further, I think I will try building some boxes similar to yours, probably in 12 cu Ft, but with curved sides like yours. I am very impressed with your build and application and would love to hear your system!! Kuddos!!:applaud:

Dan

67198

Hey Dan,
Thanks for the comments. Yes, I have a fully active (5 Way) system. Each driver has its own amp (6 amps per channel) and I have adjusted the subwoofer crossover frequency extensively. For my ears, the 2245's large cone is audibly slower than the 2 - 10" woofers and, above about 50hz, I notice an immediately less articulate sound out of the 18" vs the 10's". If however, absolute loudness were the goal, I would absolutely raise the frequency and run more power through the 18". But that is not my absolute goal. The 10" excursion really starts to become, visually, very noticeable beginning at 35 hz. When playing test tones below 35hz through the 10" drivers, they start sounding strained at higher volumes whereas playing that same tone through the 18" handles them with ease. Plus I had another overriding goal, which was to minimize the subwoofer addition on the LX521's as much as possible and preserve the fine work that was done by Mr. Linkwitz in the main system. That, my friend, is how I settled on 35hz. Thanks for the nice comments on the cabinets. IMHO, they really turned out nicely.

PC

[cosmos]

Hey Dan,
Thanks for the comments. Yes, I have a fully active (5 Way) system. Each driver has its own amp (6 amps per channel) and I have adjusted the subwoofer crossover frequency extensively. For my ears, the 2245's large cone is audibly slower than the 2 - 10" woofers and, above about 50hz, I notice an immediately less articulate sound out of the 18" vs the 10's". If however, absolute loudness were the goal, I would absolutely raise the frequency and run more power through the 18". But that is not my absolute goal. The 10" excursion really starts to become, visually, very noticeable beginning at 35 hz. When playing test tones below 35hz through the 10" drivers, they start sounding strained at higher volumes whereas playing that same tone through the 18" handles them with ease. Plus I had another overriding goal, which was to minimize the subwoofer addition on the LX521's as much as possible and preserve the fine work that was done by Mr. Linkwitz in the main system. That, my friend, is how I settled on 35hz. Thanks for the nice comments on the cabinets. IMHO, they really turned out nicely.

PC

PC,

I wonder if what you are hearing as a "slow" driver is really a timing or phase problem? Perhaps playing with those settings will clear up the muddiness? after all, 60 hz is 60 cycles per second ( a measure of time) not 57 hz with a slow driver.. I am guessing the phase or time is causing a blur of sound at the higher frequencies as the two drivers blend below, above and through the crossover frequency.. Just a thought and something to play with.

In any case, I am really happy you are enjoying your setup. It seems like it would be a superior system and the looks are stellar!

[Doc Mark]

Howdy, PC,

You've done a fantastic job on this entire system, and I doff my hat to you for the wonderful results of all your experimentation!!! Not to be pushy, and please don't take offense at my asking, but I'll be in SD this coming weekend for a big band reunion. Would you be up for a short visit, so I could enjoy your system, aurally, and visually?!!? IF, for any reason, this won't work for you, please just let me know, and I'll understand completely. However, I'll have some time on Friday, a bit on Saturday morning and evening, possibly some time on Sunday morning, and I'll definitely have time on Monday morning. Again, if this won't work for you, or you would prefer for folks you don't really know, coming to your place, just say the word, and all will be well. But, IF a short visit and demo would work for you, I'd most certainly be up for meeting you, and hearing the fruits of your extensive labors!!! Thanks for considering it, and talk to you soon. Take care, and God Bless!

Every Good Wish,
Doc (Mark)

[Champster]

Hey Doc. I'll take this off-line and send you a PM.
Paul

[Doc Mark]

Champster,

Thanks for the PM shout. I look forward to talking to you soon. Take care, and God Bless!

Doc

[Champster]

I found some photos during the construction process....6730867309673106731167312

[JuniorJBL]

Those are a very nice looking cabs Paul!! Congrats to you!! I bet they sound just amazing. :D

They are my favorite subs as well, just effortless IMO.
I just found a pair of S1S cabs (not EX) and put my 45's in them, they sound good at any volume as you have expressed and I am sure you will enjoy them for a very long time.

Congrats to a very fine system!!

Shane