I'm going to DIY a pair of floor-standing speakers from existing parts. Here is the part list:
Cabinets: ADS L1290/2
Midranges: 5 1/4" Boston Acoustics Pro 5.0LF
Tweeters: 1" Boston Acoustics Neo 1t
Woofers: 8" Boston Acoustics Rally RS8
Passive Radiators: 8" Dayton DSA215-PR
The L1290/2 cabinets consist of two chambers. They are actually the stack of two sealed enclosures. My plan is I'm going to use the upper chamber as a passive radiator system and the lower chamber as a sealed system. The midrange, tweeter, and passive radiator will be mounted on the upper chamber and only the woofer will be mounted on the lower chamber.
Crossovers for midrange and tweeter are complete units of Boston Acoustics Pro 5.2X. Crossovers for mid and woofer are none as the 5 1/4" Boston midrange will have to drive the passive radiator. Crossover for woofer (low-pass filter) will be a simple second order crossing at about 300Hz.
I'd like to ask everyone's opinion. Do these Franken-Stein speakers seem to sound alright? This is my very first time playing with passive radiator. I'm not sure whether the passive radiator and sealed system are fine to work together. Also, the 5 1/4" midranges are capable of driving those 8" passive radiators, or not? Advise me, please.
Edit: drawing of cabinets
Cabinets: ADS L1290/2
Midranges: 5 1/4" Boston Acoustics Pro 5.0LF
Tweeters: 1" Boston Acoustics Neo 1t
Woofers: 8" Boston Acoustics Rally RS8
Passive Radiators: 8" Dayton DSA215-PR
The L1290/2 cabinets consist of two chambers. They are actually the stack of two sealed enclosures. My plan is I'm going to use the upper chamber as a passive radiator system and the lower chamber as a sealed system. The midrange, tweeter, and passive radiator will be mounted on the upper chamber and only the woofer will be mounted on the lower chamber.
Crossovers for midrange and tweeter are complete units of Boston Acoustics Pro 5.2X. Crossovers for mid and woofer are none as the 5 1/4" Boston midrange will have to drive the passive radiator. Crossover for woofer (low-pass filter) will be a simple second order crossing at about 300Hz.
I'd like to ask everyone's opinion. Do these Franken-Stein speakers seem to sound alright? This is my very first time playing with passive radiator. I'm not sure whether the passive radiator and sealed system are fine to work together. Also, the 5 1/4" midranges are capable of driving those 8" passive radiators, or not? Advise me, please.
Edit: drawing of cabinets
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No, wait: You said that you own the two ADS woofers. That box has the holes for a woofer and a passive. So the woofer + passive is already done ( if viable...).
Why you say that you want to use the Boston A. midwoofer to drive the passive ? The woofers of the ADS, what's wrong with them ?
Why you say that you want to use the Boston A. midwoofer to drive the passive ? The woofers of the ADS, what's wrong with them ?
picowallspeaker
The cabinets of L1290/2 are divided chambers for upper and lower woofers. The original woofers were completely separated from each other.
To use the 5 1/4" BA mid-woofer, it requires to build an enclosure for it. So, I think to use the upper chamber as its enclosure with mounting of passive radiator at the same time.
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No, it doesn't work like that. The 300 hz crossover suggests that the woofers are doing the bass job, as their usual application. Thus the PR goes with the woofers. The mid-bass BA speakers now become a midrange speaker, so the PR is not needed. That's logical.
But, yes, usually it's advised to use a PR bigger than the woofer driving it, but the woofer itself must 'ask' for the PR, not viceversa.
Probably a box isn't needed for the mid, go figure!
But, yes, usually it's advised to use a PR bigger than the woofer driving it, but the woofer itself must 'ask' for the PR, not viceversa.
Probably a box isn't needed for the mid, go figure!
You got the speaker design philosophy backwards which will end up as a failure.
Passive radiator is just means to circumvent a certain problem, lack of space for a vent.
First you gather (measure) data of all the drivers, essentially impedance, and you use that to define cabinet loading needed for a certain low end performance.
edit: https://www.diyaudio.com/community/...cs-rs8-subs-need-enclosure-help-anyone.25816/
Passive radiator is just means to circumvent a certain problem, lack of space for a vent.
First you gather (measure) data of all the drivers, essentially impedance, and you use that to define cabinet loading needed for a certain low end performance.
edit: https://www.diyaudio.com/community/...cs-rs8-subs-need-enclosure-help-anyone.25816/
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Sorry, I should have drawn the picture of the L1290/2 at first.
Here is the drawing of cabinets. As you can see, the woofer is isolated in its own box. The midrange is in the same box with PR.
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Has anyone had resources for tutorial of tuning passive radiators with different sizes to the active drivers (delta unequals to alpha)? I couldn’t find any of them, in loudspeaker cookbooks, or even in Thiele-Small papers! (Most of them are delta equals to alpha)
WinISD is a popular free box modeling program. VituixCAD can do it as well as some other free programs that I'm not familiar with.
In addition to the programs above the rule of thumb is the passive radiator needs to be able to displace twice the air as the active driver. This is often achieved by a PR with the SAME diameter as the active driver but with twice the xmax. IF you don't have a PR with enough xmax then you will need to consider PRs larger than the active driver.
A4eaudio “IF you don't have a PR with enough xmax then you will need to consider PRs larger than the active driver.”
Yes, but the problem is I cannot find any suggestions or examples on how to design PRs which are larger than the active driver. Most of them consider at PR equals in diameter with the active driver.
You seem not to understand the matter. PR could be used to increase the low end response of the woofer, not the midrange though, for it will be high passed at 300 Hz by the x/o network. There is no point in linking PR and midrange driver.
Right, so using two of them opposed to ~cancel out their rocking/coupling modes is the norm.
As for DIYing them, one way is to start with a burned out woofer, remove its VC, spider, motor and replace with a cardboard tube for adding weight and make a spider out of durable string or start from scratch using new surrounds and a plywood/whatever disc.
https://www.google.com/search?q=diy...rlz=1C1AVNG_enUS675US675#imgrc=1Vx4tsltNFpR3M
Have you read picowallspeaker and Lojzek's posts? You do NOT want a passive radiator for your midrange driver or in the enclosure of the midrange drive. You would use a passive radiator for a bass-reflex configuration with your woofer in a situation where the port is too long to be practical or if you just prefer a passive radiator to a port tube.
If you confirm that you are trying to model a passive radiator with your woofer, and they are different sizes, I can post a screenshot in WinISD of how to model that. It is not hard, so I wonder if I am interpreting your question incorrectly.
Hmm, now that I've read the 1st post, it states the PRs are for the mids only. I've auditioned high Fs 'FR' driver speakers with cheap heavy duty cardboard based PRs (usually oval) and as long as there's something in the signal chain to keep the LF out they can perform 'good enough', especially if for BW limited AM/FM radio or similar.
There is no high-pass filter for the midrange in this case. The 300Hz point is the crossover frequency of the low-pass filter for the woofer.
The setup should be considered as a 2.5 ways system instead of a 3 way system, I think.
If you're willing to help me model it by the software, I will be really appreciated. Thanks in advance. I've added the parameters of the BA midranges below.
Boston Acoustics Pro 5.0LF
fs = 68 Hz
Vas = 0.23 cu.ft.
Qts = 0.45
Xmax = 6 mm.
Imp. = 4 Ohms
Power = 65 W
The T/S parameters of passive radiator: https://www.daytonaudio.com/product/1591/dsa215-pr-8-designer-series-aluminum-cone-passive-radiator
So, first off: you should pay attention to those people trying to help you in this thread and the other that you started. You should not be putting the midrange in an enclosure with a passive radiator and the woofer in a separate sealed enclosure. You probably should create a 3-way with the midrange in a sealed enclosure and the woofer in a separate enclosure either with a port or a passive radiator. If you are going to use a subwoofer, then you could seal the woofer too. Maybe you could do a 2.5 way, but as pointed out in the other thread, two 4-ohm drivers in parallel is going to give you a 2-ohm impedance.
But, here is how you would model a PR in WinISD.
Enter in the driver TS parameters. You do not have enough parameters above. I needed a minimum of the parameters in green text, so took some from a Dayton Audio DSA135-8 speaker. (I used Re/2, Sd, and Qes from the DSA135-8 to give me enough to work with).
Enter the project design as a Passive Radiator.
Enter the Passive Radiator Parameters (this is the DSA215-PR)
I tried using 1 and 2 passive radiators and added mass.
The Sd of the passive radiator is the surface area. I can use the 8", 6", 5" or whatever passive radiator I want. The program doesn't care, although I may not get good results from some choices.
But, here is how you would model a PR in WinISD.
Enter in the driver TS parameters. You do not have enough parameters above. I needed a minimum of the parameters in green text, so took some from a Dayton Audio DSA135-8 speaker. (I used Re/2, Sd, and Qes from the DSA135-8 to give me enough to work with).
Enter the project design as a Passive Radiator.
Enter the Passive Radiator Parameters (this is the DSA215-PR)
I tried using 1 and 2 passive radiators and added mass.
The Sd of the passive radiator is the surface area. I can use the 8", 6", 5" or whatever passive radiator I want. The program doesn't care, although I may not get good results from some choices.
Here are some simulations.
Pink is sealed 5.0 Liters. If you are making a three way you do not need an F3 of 55 Hz and this would work fine.
Green is 10.0 Liters in a vented enclosure tuned to 59Hz with a 2.5 in diameter port, 9 inches long.
All of the passive radiator models below are 10.0 liters.
Red is a single DSA215-PR (8") passive radiator with no added mass.
Dark blue is two DSA175-PR passive radiators (6-1/2") with 5 grams of added mass each
Teal is two DSA215-PR passive radiators with 32 grams of added mass each
Pink is sealed 5.0 Liters. If you are making a three way you do not need an F3 of 55 Hz and this would work fine.
Green is 10.0 Liters in a vented enclosure tuned to 59Hz with a 2.5 in diameter port, 9 inches long.
All of the passive radiator models below are 10.0 liters.
Red is a single DSA215-PR (8") passive radiator with no added mass.
Dark blue is two DSA175-PR passive radiators (6-1/2") with 5 grams of added mass each
Teal is two DSA215-PR passive radiators with 32 grams of added mass each
I found suggestion in Boston Acoustics manual, it states as follows:
"Many high performance amplifiers are capable of doubling their power at 2 ohms. In these cases, a 6dB increase will be realized. If the amplifier does not double its power at 2 ohms, a smaller increase in output will result."
If it was this case, will the 2-Ohm speaker systems cause any problems to home amplifier used? My amp is rated at 4-16 Ohms.