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Thanks for the information. Yes, Parts Express radiators can only be loaded up to 1100grams each from what I see. I'm guessing that Mach5 can also do 18" PR's? Loading mass is probably close to 2000grams each, no? Something like 15-16hz for tuning and around 7cf would work for me. You're going to try one first and if you like it, do all four Lavoce with PR's? What tuning are you shooting for? If you have the space, two drivers in one big 15cf box or so with two 21" PR's, a bass monster!!

The Eminence 21" are indeed great drivers, specially the mid-bass, clean and loud. I have mine in 4.7cf sealed boxes driven by Speakerpower HT4000 plate amp which does a great job.
 

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Discussion Starter #22
Oh, without a doubt that'll work.

Quick and dirty of the NSW sealed in 4.7, no stuffing, vs. the Lavoce (since that was what was loaded) in 7cuft with two 21" PR's, each with 3Kg added. PR design is 7dB above the sealed at 20hz. Go with 18's and your mass decreases significantly, or you could tune it even lower. Hold off though, the Mach5 PR's, if high quality and effective, are cheaper than many 18" on the market. Mach5 is in Canada, and the exchange rate is strongly in our favor. I hope they work good, the dude was great to deal with.

Chris
 

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What's your tuning, 18hz? That's a nice gain indeed. Even if the tuning is a little lower, 15-16hz, the advantage at 20hz is at least 6db's over sealed. Since is coming from Canada, how is the shipping? Any other fees? Waiting time?
 

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Discussion Starter #24
So far, no issues, but I'll update when it's in my hands.

Tuning for that setup in that box was 18hz. Like you, I'll go lower and ride the wave down to ultra low freq's. Prob 13ish hz for me.

Chris
 

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I've been getting my 2 x 21ds115's dialed in for NF the last day or 2. I'm honestly pretty surprised how loud they can go! I'm not a PR guy but cool build. Will love to see how you like them in the end.
 

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Discussion Starter #26
I've been getting my 2 x 21ds115's dialed in for NF the last day or 2. I'm honestly pretty surprised how loud they can go! I'm not a PR guy but cool build. Will love to see how you like them in the end.
Looks great, if the PR doesn't work to my liking I'll probably just have a slew of them in sealed boxes like you have there. Very pretty! What's the external dims?

Chris
 

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I appreciate all that you wrote. It just hit me in an odd way, after all of the focus, time, & intensity on the JBL boxes you planned and prototyped. Then WOOSH! Off in a new direction. Sort of like somebody who spends a great deal of time really understanding turbine dynamics, exploring what sort of compressor wheel to run ... and then abruptly unloads ALL of his turbo gear, intercooler & plumbing, and throws in a nitrous port injection system! And I really agree about practical horsepower on the street. 500-600 is plenty!


Question about the PRs: as I had such a disappointment with the PRs back 2 decades ago with the Stryke group buy, I lost interest until seeing the results using the Earthquake PRs with their seriously huge surround. My preliminary results are positive in using them with the HE-15 drivers. Have you modeled what it would look like using (for example) 4 opposing SLAPS-M12s with a downfiring driver? I just haven't seen anything (??not looking in the right places??) with the PRs you are planning to use.


By all means, CONTINUE ON in your (own personal flavor of) foolishness! Just make sure you keep your homeowner's insurance up to date :D
 

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Discussion Starter #29 (Edited)
I appreciate all that you wrote. It just hit me in an odd way, after all of the focus, time, & intensity on the JBL boxes you planned and prototyped. Then WOOSH! Off in a new direction. Sort of like somebody who spends a great deal of time really understanding turbine dynamics, exploring what sort of compressor wheel to run ... and then abruptly unloads ALL of his turbo gear, intercooler & plumbing, and throws in a nitrous port injection system! And I really agree about practical horsepower on the street. 500-600 is plenty!


Question about the PRs: as I had such a disappointment with the PRs back 2 decades ago with the Stryke group buy, I lost interest until seeing the results using the Earthquake PRs with their seriously huge surround. My preliminary results are positive in using them with the HE-15 drivers. Have you modeled what it would look like using (for example) 4 opposing SLAPS-M12s with a downfiring driver? I just haven't seen anything (??not looking in the right places??) with the PRs you are planning to use.


By all means, CONTINUE ON in your (own personal flavor of) foolishness! Just make sure you keep your homeowner's insurance up to date :D
Oh, man, to me the design was simple, the real value was in learning how to take the steps to go from an idea to a commercially viable product. So the delivery, if you will, was the process and learning. The subs as finished products in my listening room were never the real focus. That's why "whoosh" it was gone... because "it" wasn't IT. This project is, again, a bit of an iteration of that, although about 40% more personally invested for my own use. Cost is up. Performance is up. Complexity of design will be higher. The JBL's are awesome and cheap -PERFECT training ground for practicing. BTW, the original (signed, inside) sample is installed in a bar in phoenix, eq'd and set up by me along with some other subs that came from my living room. Reviews on the place mention the sound "this place has subwoofers" "serious sound system" "insane sound quality". The design worked and was cheap. Business speaking, I made enough on the sale of those to cover most of my expenses, although that wasn't the goal. I viewed the whole thing like DIY shop class with a business twist... learning and experience being the big part. It was pretty easy, my main job is a project engineer for a large aerospace company, most projects I am on are multi million dollars, so honestly it wasn't hard to slap together a timeline, basic needs, hire a couple guys to do the stuff I don't do (cad, cnc) and see what the output was like. It was a hoot!

On to PR's. I tried, and did NOT like the SLAPS. One slaps per 2 JBL's I tried and it was ok, but not getting a lot out of the PR. They require a stiff air spring, which is why Earthquake states to just stick 'em in a sealed box, no extra box volume needed. What they mean is no extra box volume wanted (in my opinion). I put two in a test box "little monster" with 10" high powered drivers. Think sunfire truesub inspiration, with 2 dual opposed 10" active drivers and 2 dual opposed slaps. The slaps didn't like the internal forces and made some awful racket that sounded like hell. It had HUGE output, 14.75" external cube, would absorb a full crown 2502 no problem. I didn't like how the SLAPS behaved. Another "whoosh", sold the subs and gave away the PR's to a local AVS buddy who we are bad influences on each other.

I have high hopes for the big girl PR's. UPS says delivery will be mid next week.... will post updates if that ends up being true!!!!

Chris
 

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Oh, man, to me the design was simple, the real value was in learning how to take the steps to go from an idea to a commercially viable product. So the delivery, if you will, was the process and learning. The subs as finished products in my listening room were never the real focus. That's why "whoosh" it was gone... because "it" wasn't IT. This project is, again, a bit of an iteration of that, although about 40% more personally invested for my own use. Cost is up. Performance is up. Complexity of design will be higher. The JBL's are awesome and cheap -PERFECT training ground for practicing. BTW, the original (signed, inside) sample is installed in a bar in phoenix, eq'd and set up by me along with some other subs that came from my living room. Reviews on the place mention the sound "this place has subwoofers" "serious sound system" "insane sound quality". The design worked and was cheap. Business speaking, I made enough on the sale of those to cover most of my expenses, although that wasn't the goal. I viewed the whole thing like DIY shop class with a business twist... learning and experience being the big part. It was pretty easy, my main job is a project engineer for a large aerospace company, most projects I am on are multi million dollars, so honestly it wasn't hard to slap together a timeline, basic needs, hire a couple guys to do the stuff I don't do (cad, cnc) and see what the output was like. It was a hoot!

On to PR's. I tried, and did NOT like the SLAPS. One slaps per 2 JBL's I tried and it was ok, but not getting a lot out of the PR. They require a stiff air spring, which is why Earthquake states to just stick 'em in a sealed box, no extra box volume needed. What they mean is no extra box volume wanted (in my opinion). I put two in a test box "little monster" with 10" high powered drivers. Think sunfire truesub inspiration, with 2 dual opposed 10" active drivers and 2 dual opposed slaps. The slaps didn't like the internal forces and made some awful racket that sounded like hell. It had HUGE output, 14.75" external cube, would absorb a full crown 2502 no problem. I didn't like how the SLAPS behaved. Another "whoosh", sold the subs and gave away the PR's to a local AVS buddy who we are bad influences on each other.

I have high hopes for the big girl PR's. UPS says delivery will be mid next week.... will post updates if that ends up being true!!!!

Chris
Interesting about your experience with the SLAPS. The build that got me to consider them (over on data-base w/ the 15" Alpine driver) had a great result, and I really liked his form factor which I used on my HE-15. Before too long I will play with that sub a bit more, pushing it with the XBS amp. I may very well use the two of them as near field subs doubling as speaker stands for surround channels.



I know that Earthquake talks of smaller cabinet volume, but they really don't have any technical explanation of 'why'. The suspension is quite stiff, but that seems simply imply less movement for given woofer excursion. It would be interesting to build a test cabinet and add blocks of wood to remove volume and see what happens. Anyway, as ryanmh1 noted in his build, none of these have proper specs and so attempting to model performance is iffy.


Did they have options in terms of stiffness of surround in your custom PR? I am curious about what aspects of this you were able to specify for your build.
 

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Discussion Starter #31
I'm a pragmatist. I also like to let people do their jobs without too much micromanaging from my part -I blend that in only as needed.

The above in mind, I merely told Mark that I wanted a 21" diameter PR that would support mass suitable to extend tuning as far below 20hz as possible if put in a 6cuft box. Minimum of 2500g. Xmax was largely irrelevant for me as the LaVoces only throw 14mm (let's call it 20mm) and long throw 21" suspension is more the norm vs. the exception. With reported travel the better part of 60mm one way, it's a non issue. Could I use two LaVoce's for ONE PR? Not going to find out, as these suckers will have enough mass to require force balancing.

Why don't I care too much? I'll only be giving each LaVoce 1200W.

All of this is to say for the first iteration I just mention the bare needed specs: Suitable diameter, can support mass for target tuning in target enclosure size. I'll get what I get. If I don't like it, THEN I'll ask for some tweaks. Remember, meanwhile, PSI is allegedly making my PR, visualize teams of scientists in lab coats and clip boards, definitely wearing safety goggles, coming up with their version. Hope it's cool. FWIW I told PSI the same thing. They just said "Ok, send us your frame, we'll ping you when it's done." I await their ping. I can tell you this, if I get the Mach5, test it, like it, I'll design around it. I am half suspicious that may come about before I hear back from PSI. We'll see!

The SLAPS is a different animal, no spider, just the surround and a partial surround (chunks removed) on the back side.

Chris
 

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Discussion Starter #32
Update: Pierce Audio got back to me:

"We can build 21" and 24" PR's no problem. The 21" have a long throw spider pack good for 75mm p-p excursion and the 24" is good for 100mm p-p excursion. We use a solid aluminum puck to attach the spider to cone joint which we thread for attaching further weight for tuning. Adding 3kg or more would not be a problem mechanically. We can build these anytime and will also be adding a full HT section to our website soon which will include the passive radiators also."

Sneak preview photo stolen from their FB page attached below. The +/- 75mm is adequate for the LaVoce, if not tons of margin. The 24" would be cool but isn't needed for my application, particularly when considering that I want to use 2 of them per box for force balancing purposes, although I could certainly see it being a viable option for a huge quad 21" build, have 4 21's on the front face and side firing 24" PR's.
 

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The 21" have a long throw spider pack good for 75mm p-p excursion and the 24" is good for 100mm p-p excursion. We use a solid aluminum puck to attach the spider to cone joint which we thread for attaching further weight for tuning. Adding 3kg or more would not be a problem mechanically.

That all sounds great, until you start doing the math on what they will cost! :D
 

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Discussion Starter #35
That all sounds great, until you start doing the math on what they will cost! :D
Basically $600 or less to have dual 21" PR's in a big dual 21" active driver setup. I don't think it's unreasonable. Ports will always be less expensive, that's not the goal or the desire. Total package, PR alignments (if designed right) can do some things that would be very difficult if not impossible with ports -hence the whole thread!

But yes, any time you're using multiples of decent drivers cost starts going way up. I feel like this is going to hurt a bit by the time I'm done.

Chris
 

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Discussion Starter #37
I was holding back on price info until I see who does what.

I can tell you that is was NOT cost effective for me to buy a 21" frame from my local guy and ship it to PSI, nevermind what they do with it and that cost; frame alone cost me $75 or $85, I can't remember, but it was expensive to ship across the country -nearly $100, so I'm at $175 BEFORE PSI actually turns it into a Passive Radiator and ships it back.

Mach5 offering end up costing me well under $250 shipped from Canada. The US/Canadian dollar exchange rate is in our favor.

The estimate from Pierce for the 21" PR was a hair over $300 shipped.

Performance will play a role of course, but right now the Mach5 specs are lending themselves to serious consideration, and the price is more than reasonable.

Chris
 

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