Another day, another idiot trying to build a BP4
- By halligan
- Subwoofers
- 5 Replies
Another day, another idiot building a BP4
First post and of course, asking for help. I've done a ton of reading and I think I'm on the right track but really would like some sanity checking. The wife has a Can Am Defender (Side by Side) and wants some "boom boom". It's an open model and I'm putting the box in the bed so no cab. I'm pairing the subs with a set of wake tower speakers that come in around 60 Hz.
What I'm using:
TS Params:
I used these formulas to back my way into the following specifications:
Putting all of that into WinISD and then adjusting the port to somewhat reasonable air velocity got me here:
The above is modeling a single driver so when I build I'll double the diameter of the port thinking being it's two subs and WinISD is modeling one driver.
That brings me to the box design.
The box is 51" wide by 20.50" tall by 20" deep (front to rear). The port total width is 49.5" by 2" tall (inside dimensions) and 11.72" long.
Where I'm starting to struggle is first, is all of this in the right direction or have I gone badly wrong somewhere?
Second, I know port volume is not included in box volume, but if I change my port length to tune then the box volume will change which changes the port length which changes the volume, etc. Any tips? Or have I designed the port incorrectly by being above the speakers?
Should I redesign the box completely and fire sideway? Move the port? Should I just surrender and go back to IT a failure in the audio world?
First post and of course, asking for help. I've done a ton of reading and I think I'm on the right track but really would like some sanity checking. The wife has a Can Am Defender (Side by Side) and wants some "boom boom". It's an open model and I'm putting the box in the bed so no cab. I'm pairing the subs with a set of wake tower speakers that come in around 60 Hz.
What I'm using:
TS Params:
I used these formulas to back my way into the following specifications:
- fL 32.40750349
- S 0.6
- fH 74.74941047
- Qts 0.86
- Front Chamber 1.3968 (per sub, separate chambers)
- Fs 38.09
- Rear Chamber 1.448182937 (per) 2.896365875 (shared)
- fL Factor 0.7317
- Tune 49.22025233
- fH Factor 1.6877
- VAS 0.97
- Qbp 1.1113
Putting all of that into WinISD and then adjusting the port to somewhat reasonable air velocity got me here:
The above is modeling a single driver so when I build I'll double the diameter of the port thinking being it's two subs and WinISD is modeling one driver.
That brings me to the box design.
The box is 51" wide by 20.50" tall by 20" deep (front to rear). The port total width is 49.5" by 2" tall (inside dimensions) and 11.72" long.
Where I'm starting to struggle is first, is all of this in the right direction or have I gone badly wrong somewhere?
Second, I know port volume is not included in box volume, but if I change my port length to tune then the box volume will change which changes the port length which changes the volume, etc. Any tips? Or have I designed the port incorrectly by being above the speakers?
Should I redesign the box completely and fire sideway? Move the port? Should I just surrender and go back to IT a failure in the audio world?
Need help please, wharfedale diamond 8.2 tweeter damaged
- By availlyrics
- Multi-Way
- 4 Replies
Attachments
Sealed enclosure for Alpair 5.3
- By Avondalenaim
- Full Range
- 28 Replies
Hello from a full range virgin 😀
I will outline my plan. I want to build a sealed enclosure for this little 5.3 full ranger that will be high passed with a first order filter incorporated in the input stage of my power amp (passive line level).
I want to use this with a 6.5" mid bass which is in a TL enclosure already kindly built and designed for me by B&W 🙂 I will just remove the tweeter and drastically reduce the low pass filter. The low pass for the 6.5" mid bass will be at 500 Hz which is roughly the middle of the baffle step. The high pass for the 5.3 will be a first order at 500Hz and also done passively at line level in the input stage of my power amplifier.
Can you kind people please suggest a sealed cabinet volume for the 5.3 ? I obviously know it's VAS and Qts already but I am unsure how an ideal volume would be changed by high passing it at 500Hz.
I want to put it in a sphere or B&W style tear drop and put it on top of the B&W cabinet and set back a little to time align it with the 6.5" woofer.
Many thanks
I will outline my plan. I want to build a sealed enclosure for this little 5.3 full ranger that will be high passed with a first order filter incorporated in the input stage of my power amp (passive line level).
I want to use this with a 6.5" mid bass which is in a TL enclosure already kindly built and designed for me by B&W 🙂 I will just remove the tweeter and drastically reduce the low pass filter. The low pass for the 6.5" mid bass will be at 500 Hz which is roughly the middle of the baffle step. The high pass for the 5.3 will be a first order at 500Hz and also done passively at line level in the input stage of my power amplifier.
Can you kind people please suggest a sealed cabinet volume for the 5.3 ? I obviously know it's VAS and Qts already but I am unsure how an ideal volume would be changed by high passing it at 500Hz.
I want to put it in a sphere or B&W style tear drop and put it on top of the B&W cabinet and set back a little to time align it with the 6.5" woofer.
Many thanks
TU-8600 with TKD 2CP601
It is possible to use TKD 2CP601 with TU-8600
Here is the volume pot PCB designed by Mr Fujita
If your are interested, please let me know
Paul Carmody Carrera build - Completed and audibly Elated!
I’ve always appreciated good audio but these are my first DIY speaker build, which I finished a few months ago and really couldn’t be happier. That laid back sound was really what I was looking for and the bass is phenomenal for the speaker size. A big shout out to Meniscus Audio, the diyaudio community and of course Paul Carmody for designing such a terrific speaker.
Sadly I purchased the kit before realizing that WAF, (wife appreciation/approval factor), was going to derail speaker placement. As such I had to shrink the cabinet height by 1” as one speaker had to fit in a bookshelf. And they are a little close to a wall so I currently have the rear ports stuffed with acoustastuff - not optimal but neither is my wife’s nagging.
I used some B&W 50mm port tubes and then 3d printed a spacer to get the correct tuning down to 42-43hz.
I used 3/4” baltic birch, which was great to work with but not very forgiving when it came to staining - the finish came out kind of blotchy. I also chose to use solid birch edge banding which was a bit of a challenge for my wood working skills. I’ll probably veneer my next project. I also had some leftover Noico butyl rubber which I lined the inside of the cabinet with. I don’t know if the sound deadening mat really made a difference but it certainly wasn’t being put to use sitting in the garage.
Sadly I purchased the kit before realizing that WAF, (wife appreciation/approval factor), was going to derail speaker placement. As such I had to shrink the cabinet height by 1” as one speaker had to fit in a bookshelf. And they are a little close to a wall so I currently have the rear ports stuffed with acoustastuff - not optimal but neither is my wife’s nagging.
I used some B&W 50mm port tubes and then 3d printed a spacer to get the correct tuning down to 42-43hz.
I used 3/4” baltic birch, which was great to work with but not very forgiving when it came to staining - the finish came out kind of blotchy. I also chose to use solid birch edge banding which was a bit of a challenge for my wood working skills. I’ll probably veneer my next project. I also had some leftover Noico butyl rubber which I lined the inside of the cabinet with. I don’t know if the sound deadening mat really made a difference but it certainly wasn’t being put to use sitting in the garage.
Did I do this correctly? Results in Hornresp don't match WinISD
I copied the TS specs from WinISD to Hornresp. The models match fairly well except the port is only 9.7cm long in Hornresp while it is 27.3 cm in WinISD This seems like a huge difference. I did change the model to represent a MLTL in HornResp.
Can someone please check my work?
Can someone please check my work?
Slat/hole helmholtz bass absorber in wall
- By AlMaEn
- Room Acoustics & Mods
- 3 Replies
Hi everyone. 
Please need some help and advice...
I am trying to convert my cellar to a musicroom. Most for stereo and sometimes movies or with a cold one watching Lfc play football. Concret walls and celings/ floor. Low in height just 208 cm. Room is 580x364 so appr. 21 m2. Not the best start. A wall to wall thick carpet and a acoustic ceiling is planned. The good thing is that one wall is made of fibreboard and gypsum. And i have made place of some sort of a bass absorber. I have room for a 60x208 cm trap that is almost 45 cm deep in each corner. My first thought was a slat absorber but hard to come down to room modes frequencies. I love the look of a slat wall made of walnut or alike. My lowest axial mode is 29 Hz according to Amroc calc. Next is 48 Hz at sidewalls. Then 59 and 88 Hz and so on. I plan to have speakers at the wall with basstrap playing at longer dimensions of the room. It seems to be easier to get down to lower modes with a wall with round holes instead of slats. Or is it best just to fill it up with absorbing material? Or will it be
a overdamped room? Is it possible to fix the modes from 30Hz to say around 240 Hz. It will be a large bookcase or something for storing at back wall behind listening position. First reflexes will be treated with a thick absorbent on sidewalls and ceiling. Back of room walls will be more diffuse/reflecting than absorbing I think. Any suggestions from you about my room and planning?
/YNWA
Please need some help and advice...I am trying to convert my cellar to a musicroom. Most for stereo and sometimes movies or with a cold one watching Lfc play football. Concret walls and celings/ floor. Low in height just 208 cm. Room is 580x364 so appr. 21 m2. Not the best start. A wall to wall thick carpet and a acoustic ceiling is planned. The good thing is that one wall is made of fibreboard and gypsum. And i have made place of some sort of a bass absorber. I have room for a 60x208 cm trap that is almost 45 cm deep in each corner. My first thought was a slat absorber but hard to come down to room modes frequencies. I love the look of a slat wall made of walnut or alike. My lowest axial mode is 29 Hz according to Amroc calc. Next is 48 Hz at sidewalls. Then 59 and 88 Hz and so on. I plan to have speakers at the wall with basstrap playing at longer dimensions of the room. It seems to be easier to get down to lower modes with a wall with round holes instead of slats. Or is it best just to fill it up with absorbing material? Or will it be
a overdamped room? Is it possible to fix the modes from 30Hz to say around 240 Hz. It will be a large bookcase or something for storing at back wall behind listening position. First reflexes will be treated with a thick absorbent on sidewalls and ceiling. Back of room walls will be more diffuse/reflecting than absorbing I think. Any suggestions from you about my room and planning?
/YNWA
Philips EL6405
- By invacuo
- Tubes / Valves
- 4 Replies
Hi,
I have this amplifier (Philips EL6405) and want to connect it to low impedance speaker. Something between 4 or 16 ohms.
The output transformer has 10V, 25V and higher.
The output power is 20W. What is the best speaker impedance to match it to the 25V or 10V.
Thanks for your help.
I have this amplifier (Philips EL6405) and want to connect it to low impedance speaker. Something between 4 or 16 ohms.
The output transformer has 10V, 25V and higher.
The output power is 20W. What is the best speaker impedance to match it to the 25V or 10V.
Thanks for your help.
buzzy ground loopiness
- By ultrachrome
- Analog Line Level
- 4 Replies
Trying to finish up a rebuild project from years ago. It's a Rosenblit Grounded Grid preamp built on a turret board and installed in a Lite Audio enclosure with V-03 relay attenuator.
This was my stab at the grounding but it must not be correct.
It seems to be something with the V-03 board. I did try bypassing with an Alps RK27 and the buzzing went away.
A previous incarnation kept the signal grounds off the V-03 but the V-03 itself still had to be grounded to avoid a deafening hum.
This was my stab at the grounding but it must not be correct.
It seems to be something with the V-03 board. I did try bypassing with an Alps RK27 and the buzzing went away.
A previous incarnation kept the signal grounds off the V-03 but the V-03 itself still had to be grounded to avoid a deafening hum.
Attachments
Beer Budget Beam Steering
- Multi-Way
- 60 Replies
In pro audio, end fire arrays are a popular way to do beam steering.
Here's how they work:
You take a couple of subs, and you place them in a line.
You pick a frequency where you want to control directivity.
You move one sub behind the other, at a distance equal to one quarter wavelength of that frequency.
And then you delay the first by a distance equal to that length.
So let's run a sim on this.
For my sim I am going to use a frequency of 200Hz.
It's true that this frequency is high, but I am using this frequency because of the limits of my simulation tool. But please note that all of this is geometric; the same things that happen at 200Hz will happen at 40Hz if you multiply all of the dimensions by five.
If we want to control directivity at 200Hz, then we'll want to space the front woofer apart from the rear woofer by 42.50cm. That's because 200Hz is 170cm long, and 42.5cm is one quarter of that.
In the sim, my woofers are 7" in diameter, and their enclosure is a cube that measures 8" x 8" x 8". (And, again, note that you'd get the same polar pattern at 40Hz with an enclosure that measures 40" x 40" x 40".)
Here's the wavefront shape of this array at 200Hz. We clearly see the 'heart shaped' cardioid pattern.
If we go down one octave, to 100Hz, our array is a plain ol' monopole. This is one of the 'neat' things about end-fire arrays. When they lose their directivity control, they don't lose efficiency like a cardioid or a dipole. They just behave like a conventional box.
At 400Hz, our array is a dipole. This is going to limit the bandwidth of our array, which is one of the reasons you only want to use end-fire arrays over a narrow bandwidth of 1-2 octaves. Obviously, this is no problem for subwoofers.
You may be curious why the end-fire array goes dipole. Here's why: We design it to work at one frequency, where the rear wave is 90 degrees out-of-phase. But that means that one octave ABOVE our target frequency, it's going to be 180 degrees out of phase. That's how it goes dipole.
Here's how they work:
You take a couple of subs, and you place them in a line.
You pick a frequency where you want to control directivity.
You move one sub behind the other, at a distance equal to one quarter wavelength of that frequency.
And then you delay the first by a distance equal to that length.
So let's run a sim on this.
For my sim I am going to use a frequency of 200Hz.
It's true that this frequency is high, but I am using this frequency because of the limits of my simulation tool. But please note that all of this is geometric; the same things that happen at 200Hz will happen at 40Hz if you multiply all of the dimensions by five.
If we want to control directivity at 200Hz, then we'll want to space the front woofer apart from the rear woofer by 42.50cm. That's because 200Hz is 170cm long, and 42.5cm is one quarter of that.
In the sim, my woofers are 7" in diameter, and their enclosure is a cube that measures 8" x 8" x 8". (And, again, note that you'd get the same polar pattern at 40Hz with an enclosure that measures 40" x 40" x 40".)
Here's the wavefront shape of this array at 200Hz. We clearly see the 'heart shaped' cardioid pattern.
If we go down one octave, to 100Hz, our array is a plain ol' monopole. This is one of the 'neat' things about end-fire arrays. When they lose their directivity control, they don't lose efficiency like a cardioid or a dipole. They just behave like a conventional box.
At 400Hz, our array is a dipole. This is going to limit the bandwidth of our array, which is one of the reasons you only want to use end-fire arrays over a narrow bandwidth of 1-2 octaves. Obviously, this is no problem for subwoofers.
You may be curious why the end-fire array goes dipole. Here's why: We design it to work at one frequency, where the rear wave is 90 degrees out-of-phase. But that means that one octave ABOVE our target frequency, it's going to be 180 degrees out of phase. That's how it goes dipole.
