I have finally found an audiophile high SPL speaker to build (1 Viewer)

[James W. Johnson]

After alot of research and educating myself more about loudspeakers I have finally found a speaker to build that will sound fantasic and have super high SPLs(they go pretty loud, with only 250watts applied they should reach 120dB)
First off thanks to Jack Gilvey who first sent me to Pi speakers to have a look at what they have to offer.
When looking for a speaker it was important not only that the speaker puts out high SPLs but also that it sounds good.
I noticed along time ago that many, many home audio speakers use 5.5 to 6.5" midbass drivers, I have always thought that the reason for this is because they could more accuratly produce music in a home hifi environment, however this is very incorrect, 5.5 and 6.5" drivers are chosen because they are what is demanded by the the home users budget and asthetics.
The truth is ...
1. My JBL 15" driver's linearity between 40 and 1.8Khz is superior to a 6.5" driver
2. My JBL 15" driver's distortion between 40 and 1.8Khz is WAY superior to any 6.5" driver.
3. My JBL 15" driver's efficiency between 40 and 1.8Khz is higher than any 6.5" driver.
4. My JBL 15" driver's maximum output between 40 and 1.8Khz is MUCH higher than any 6.5" driver.
I have learned that reaching super high SPLs just cannot be done without the technology in the speakers I have chosen.
The drivers the Four Pi Pro Series speaker uses is the JBL 2226H 15" driver http://www.PiSpeakers.com/JBL_2226.pdf
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James' DIY speakers

 

[James W. Johnson]

I should add that if you would like a pair of these bad boys but don't want to build them yourself Pi speakers sells them finished as well.www.pispeakers.com
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James' DIY speakers

 

[Dustin B]

So that quest for a louder longer lasting ring in your ears has found it's answer

Have you checked out Klipsch's newest reference speaker, the RF7. 102 db/w/m

 

[Greg Monfort]

Welcome to my world.
1, 2, & 3 are only true under certain circumstances, but overall I prefer the 15" for the reasons stated. Another reason is a 15's polar response reduces reflections for better imaging.
Actually, I prefer two/chnl, horn loaded.

At a system sens of 107dB/W/m, the 130dB of dynamic range in-room needed for the illusion of front row center at the Boston Pops is a reality. The downside is that they're so large that I'm limited to stereo due to room/$$ constraints.

GM
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Loud is beautiful, if it's clean

 

[James W. Johnson]

Greg, I have always wondered what sort of speakers you own, what do you have if you don't mind saying?
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James' DIY speakers

 

[Mark Seaton]

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Actually, I prefer two/chnl, horn loaded. At a system sens of 107dB/W/m, the 130dB of dynamic range in-room needed for the illusion of front row center at the Boston Pops is a reality. The downside is that they're so large that I'm limited to stereo due to room/$$ constraints.
GM
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Hi Greg,
You won't hear me dissagree about those sorts of dynamics and horn loading. Last week I got to play with both at home and at ServoDrive/Sound Physics Labs, a pair of the TD-1s and a pair of Contras

. With each TD-1 on top of a Contrabass, the Contras were looking for help while the TD-1s just wanted to keep going! I know you can refference those levels 8). With a 2.8V sensitivity of 103dB/1M, Tom Danley actually tested one speaker to produce 137dB from 1M with 800W pink noise input. While I won't be able to maintain the directivity of the TD-1 below 300Hz with my Lambda Unity horn, the pair of Lambda TD15M drivers covering the midbass should allow me to truely reach those 130dB peak levels cleanly from 80Hz up... and in a very modest sized package to boot! Ok, so this system is priced at about $1300 per speaker, but show me another option I can fit in my room for that price .
Like you always have said...
"Loud is beautiful, if it's clean"
Mark Seaton

 

[ThomasW]

James I question if the smaller Pi's really offer true high-end performance. That's a pretty small box......
I'd look long and hard at the Lambda Unity horns (especially considering the limited time DIY pricing), Mark S. can certainly provide all specifics on those.

 

[Greg Monfort]

JJ,
In a nutshell, each chnl currently consists of a Contrabass for

 

[Peter Johnson]

I may be way off base here (I apologise in advance if I am), but....
A 1.8kHz tone through a 15" driver is gonna be literally coming out in a straight line, it will be beaming SOOO bad. Move 10cm off axis, and its no longer going to be flat.
Secondly, you are assuming all drivers sound the same. So the Scanspeak 8545 sounds the same as the 6.5" woofer I saw at tandy (is RS in AUstralia) for $AU20 (=$US10)? I dont think so.
There is a reason why people use a 6.5" woofers etc for midrange. If there wasn't, people would have done it by now.

 

[James W. Johnson]

I'd look long and hard at the Lambda Unity horns (especially considering the limited time DIY pricing), Mark S. can certainly provide all specifics on those.
>>>>>>>>>>>>>>
$$$$$$$$$.....I have been to Lambdas website 30 times drueling over the Unity horns , damn they are expensive!
Look, I consider you , Thomas, Greg Monfort and Mark Seaton to be my idols. If you guys say these Unity Horns are really that great I still can opt for the Unity Horns instead...the problem is I am not a speaker designer and I don't want to have $2600 worth of nice components put together in a crappy sounding speaker, I feel much more comfortable building a speaker that has already been proven.
Too bad Lambda does not offer at least one free plan utilizing their parts.
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James' DIY speakers

 

[James W. Johnson]

Last week I got to play with both at home and at ServoDrive/Sound Physics Labs, a pair of the TD-1s and a pair of Contras . With each TD-1 on top of a Contrabass, the Contras were looking for help while the TD-1s just wanted to keep going! I know you can refference those levels 8). With a 2.8V sensitivity of 103dB/1M, Tom Danley actually tested one speaker to produce 137dB from 1M with 800W pink noise input>>>>>>>>>>>>>>>>>
Mark, tell me about the TD-1 , what are they composed of, and is the $3300 price tag per speaker?
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James' DIY speakers

 

[Mark Seaton]

"Mark, tell me about the TD-1 , what are they composed of, and is the $3300 price tag per speaker?"
James-
Yes, that's $3295 each for a 120 lbs. speaker. This also includes all sorts of connection flexibility, and "flyware" so they can be suspended. ~60 of these just went in or are going into Blossom Park in Cleveland where after a demo, the Cleveland Symphony Orchestra's conductor had the spec changed from Meyer to Sound Physics Labs/ServoDrive, NO EXCEPTIONS. That's no small compliment.
The TD-1 is a 30 deg horizontal by 60 deg vertical, 3 way Unity speaker. It uses the exact same B&C compression driver and 4 midranges as seen in the Lambda kit, and all other Unity products they make (4 now, although only 2 on the website). The TD-1 uses a pair of 12" drivers loaded into the horn much like the midranges are, but further down the lense of the horn. The 30deg horizontal also allows these to easily be arrayed to behave just like a single unit with wider dispersion as can be seen on their web site listed below. Note that the 30deg horizontal angle halves the space the sound is dispersed over, and thereby increases sensitivity by 3dB(or is it 6?) over the 60x60 horn.http://www.servodrive.com/spl/td1.shtml
If you look at the Unity VFL, you see it is rather closely related to the Lambda horn, yet it is a 3 way. FYI- the "VFL" designation carried the in-house name "Very F#@&$n' Loud" 8), but this was before the TD-1. Those can be used as a reasonable basis for what the midrange and tweeter are capable as they too use the same driver complement.http://www.servodrive.com/spl/unity.shtml
As for offering a finished kit, I agree that would be a great idea, but there are many reasons this hasn't been done yet, not least of which is available time and timing. In any case, you should realize that from 300Hz up, the design is done and complete for you, as is the 4th order High Pass filter for the Lambda Kit. All you need to add is midbass, and a 4th order filter to complement it. A schematic for one example is at the bottom of the Lambda Unity page. We can easily scale this to the right load for your choice of drivers. So, all you really need to do is to give each TD15M 2.25 cu.ft. of space, sealed, and plug in the crossover. The toughest part is getting levels to match, which still isn't all that hard, and yes, I'd be happy to help/share the low-pass crossover I implement. Here's another thing to consider: If you end up not completely satisfied with the passive crossover implementation, the use of an active, 4th order crossover makes the solution VERY easy. Just plug in, set to ~300Hz, and adjust the levels.
Mark Seaton

 

[Greg Monfort]

Active/bi-amp between the Unity/TD1 is the only way to go IMO, and makes dialing in time alignment a no-brainer if you use a pro XO.
Halving the radiated space = 3.01dB increase.
GM
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Loud is beautiful, if it's clean

 

[Mark Seaton]

I will agree with you Greg that active is a great way to go for the 300Hz crossover. Right now I'm just using a Rane AC22 borrowed from a friend. I'll first be implementing a passive crossover for a variety of reasons lying more in curiosity and the challenge as well as then having the ability to show it off to some friends who haven't yet opened their eyes to active systems. After I get the passive crossover done, I'll then be working on a fully or mostly active crossover to take real advantage of the HUGE efficiency of the midranges. Of course the crossover for the mid-B&C is no small task at all with the phase alignement and frequency response correction needed. It will be a long term, pet-project. Something to play with for a long time.
Take Greg's recommendation that the simplest "plug and play" option for a DIYer would in fact be an active crossover. The proper implementation of which would be a 1st order HP for the horn, and ~ 4th order Linkwitz-Riley filter for the low pass.
Mark Seaton

 

[ThomasW]

James
Buy only the Unity horn kit now. Next build an altar and put them on it. Pray/chant/sing to them. Then do lot's of overtime saving your $$$$$. Buy the rest of the parts as time/money permits. Built the 2-way first, then upgrade to the 3-way. This is how many of us got started. We couldn't afford to get everything at once so it was purchased piece by piece until the project was completed!

 

[Greg Monfort]

No kidding TW! There's no way I could have afforded my system if I'd had to buy new. $2200 in '69 was about the downpayment we put on the house, and over half what we paid for the S.O's loaded '70 350 SS Camaro. I lucked out and got mine for the price of some beer and a truck rental (I'm guessing ~$250 in today's $$) when a big cinema was gutted, then spent the better part of a year saving up (plus had to sell my A7 cabs) to get the LF drivers re-zapped/reconed.
But boy was it worth it IMO.
GM
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Loud is beautiful, if it's clean

 

[Greg Monfort]

>I may be way off base here (I apologise in advance if I am), but....
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Yes, and no, at least WRT this speaker.
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>A 1.8kHz tone through a 15" driver is gonna be literally coming out in a straight line, it will be beaming SOOO bad.
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Pretty much.
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> Move 10cm off axis, and its no longer going to be flat.
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Right, on average, a 15" begins beaming at ~332Hz (13" effective dia, or 13560"/(13"*pi)), and is -3dB/45deg off-axis by 2x this (an octave), or ~665Hz. Indeed, if you look at the 2226H's FR, it's very close to this. At 1.8kHz, combined with the inductive roll-off, it's -18dB/45deg.
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>Secondly, you are assuming all drivers sound the same. So the Scanspeak 8545 sounds the same as the 6.5" woofer I saw at tandy (is RS in AUstralia) for $AU20 (=$US10)? I dont think so.
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Hmm, I didn't get that from his admittedly rather general comments, though if they were all in the same alignment and were only reproducing the BW where the WLs are > the piston area, they would. Since that's not normally the case, they will indeed sound different.
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>There is a reason why people use a 6.5" woofers etc for midrange. If there wasn't, people would have done it by now.
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Yes (or at least to the thought I think you're trying to convey), but it's the opposite of what you want WRT a HT speaker's polar response to be. Small drivers give a ~spherical (omni-directional) response to a much higher frequency than a larger driver, whereas for HT (and HIFI IMO) we want limited off axis response to minimize the comb filtering and early reflections that ruins the multi-channel imaging/soundstaging.
That said, the driver won't be used to 1.8kHz at any disruptive volume since the XO point will be much lower (I'm assuming ~800Hz based on the components), where the polar response is about the same as the mid horn. This combo will provide a much more uniform power response out to the ~15deg max off-axis of a typical HT compared to the 6.5" that normally mates to a cone/dome HF.
GM
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Loud is beautiful, if it's clean

 

[James W. Johnson]

Mark, are your Unitys mounted like this,does the Unity kit come with this stand?
Do you plan on building a box for two 15" driver and just set the Unity on top?
Does the Unity sound different if you box it up?
Sorry to flood you with questions but they have to be asked before I shell out this cash.
Thanks

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James' DIY speakers

 

[Jack Gilvey]

That looks too cool. Thank God for cable modems.

 

[Mark Seaton]

James,
First, yes, the "footer" that you see holding up the horn in the picture is included in the kit. I am actualy just using the wedge at the moment, and not the full size footer. Note, the wedge by itself won't make for a stable mounting, and I have a second support "stand" which suppports the magnet of the compression driver. I have mine configured so I can have the front of the mouth hang over the front of the bass box, which sets back the woofers closer to more closely align the front to back acoustic centers of the horn and woofers. The depth of the 15" driver will help with this too. After I do some playing with actual positioning, I am planning to build a an enclosure on top of the bass boxes which will enclose the raw drivers, and likely 3/4 of the horn itself. This is by no means settled yet, but I enjoy being able to play and experiment, so that's why I'm not too worried about it, but have plenty of ideas.
As for placing it in a box, you can see that done in the 7' tall monsters that Lambda made, and in the two new products from Sound Physics Labs. The reason the size/shape of a box can change the sound is because of the reflections and the size of the baffle a driver is mounted on. This is NOT an issue with the Unity horn. They will produce almost identical results out on the stand as they would mounted flush in a wall! This is because above 500Hz, very little energy comes out of the 60 x 60 degree lense pattern, and at 300Hz radiation is still at about 120deg. In the future one of the kit options from Lambda is supposed to be the unity in a ~17" cube, of course at the new price though. James I get the impression you are a reasonably resourcefull builder, probably much more capable in this area than I, and I'm confident you can come up with something you can construct. The nice thing is, as long as you don't obstruct the front area of the mouth of the horn, you won't affect the sound, so options are rather open, and hence one of it's unique beauties for the DIYer. So go ahead and bounce your ideas off the rest of us.
Mark Seaton