I have a pair of old speaker cabinets - they are quite nice. The drivers are broken so I would like to replace them. I would appreciate any pointers for driver/tweeter pairs, speaker-driver simulators, and cross over simulators or pointers. The mid-base box is ported - complicating driver selection. I'm a beginner but versed in some engineering so I might understand a spec but not know its relative importance. I have a Apple Mac for running simulations.
Any help is appreciated. If I missed a post that has all this, I'm sorry, and would appreciate being told where to go (no pun intended).
The speaker cabinet:
One of the more important specs above is the hole already made for the old mid-bass driver. I want the new driver to fit that. I can, optionally, pair the speakers with a sub.
I plan to build the crossovers if they become too pricey. I would like to keep the drivers(2)/tweeter(2) budget under $400. The amplifier to drive the speaker is a fairly clean 125 W/channel into 8 ohms, class D that will drive 4 ohms without an issue.
Thank you.
Any help is appreciated. If I missed a post that has all this, I'm sorry, and would appreciate being told where to go (no pun intended).
The speaker cabinet:
- tweeter is mounted in a free standing way allowing a maximum face dimension of 4" x 4" (102 x 102mm)
- mid-bass driver is in a box with internal dimensions of 16" x 8" x 10 1/8" (406 x 203 x 257mm) or 0.748 cu ft (21.2 Liters)
- the box is ported with a 2" ID (50.8 mm) pipe running 3.3" (83.8mm) into the internal space and through 3/4" (19.0mm) of cabinet.
- the port is pointed downward and the box is suspended in the speaker frame to allow air to flow freely to and from the port
- the mid-bass driver is mounted on the 16 x 8 face and has a 5 3/4" (146mm) hole center horizontally and 7" (177.8mm) down from the top
- the box contains 2" of insulation material against the wall opposite the driver.
- what I think I need of a mid-bass driver: Fs = 40-50Hz, Qts = 0.35-0.45, Vas = 0.52-0.88 cu ft (15-25 L)
- my hope is to have a very accurate/neutral speaker with average or better off-axis listening.
One of the more important specs above is the hole already made for the old mid-bass driver. I want the new driver to fit that. I can, optionally, pair the speakers with a sub.
I plan to build the crossovers if they become too pricey. I would like to keep the drivers(2)/tweeter(2) budget under $400. The amplifier to drive the speaker is a fairly clean 125 W/channel into 8 ohms, class D that will drive 4 ohms without an issue.
Thank you.
driver
Vas = 21.2 lts
fs = 50 Hz
Qts = 0.42
box
Vb = 0.76 ft3 = 21.5 lts = L x W x H
f3 = 48.19 Hz
fb = 48.19 Hz
Dv = 2 in = 5 cm
Lv = 3.3 in = 8.06 cm
Vb: Speaker Box Internal Volume
f3: 3dB Cutoff Frequency
fb: Enclosure Resonant Frequency
Dv: Port Diameter
Lv: Port Length
Vas = 21.2 lts
fs = 50 Hz
Qts = 0.42
box
Vb = 0.76 ft3 = 21.5 lts = L x W x H
f3 = 48.19 Hz
fb = 48.19 Hz
Dv = 2 in = 5 cm
Lv = 3.3 in = 8.06 cm
Vb: Speaker Box Internal Volume
f3: 3dB Cutoff Frequency
fb: Enclosure Resonant Frequency
Dv: Port Diameter
Lv: Port Length
Seas fits. DXT tweeter + U16 midwoofer has a design from Goran. https://www.audioexcite.com/?page_id=2386 - not sure on impact of tweeter mount and cabinet volume, but you could have a look at the design.
U16 also currently on sale at Madisound.
If you make it a closed box for use with subs, the Qb will be very low, promising tight bass, but best to model and play with stuffing probably on the lighter side, reduce the volume accordingly if needed.
U16 also currently on sale at Madisound.
If you make it a closed box for use with subs, the Qb will be very low, promising tight bass, but best to model and play with stuffing probably on the lighter side, reduce the volume accordingly if needed.
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@--Oz-- It's not out of the question, but I watched a friend do this a few months ago and getting a perfect fitting product was challenging. In my case, perhaps more so since I can read no branding of any kind on the old drivers. The rubber around the cones is shot but so is the center piece in front of the voice coil - it's actually half gone on one speaker (the other, the noisier of the two, I have not opened up yet.)
@motokoc thanks for the suggested candidates. I will check each out. The tweeter is not within a cabinet at all - it is essentially glued upright in the same plane as the mid-bass driver. Playing with the cabinet, its stuffing and port, is a good idea but it would be much better if I could do so with many drivers to experiment with. Too bad that's not the case for me. I will try it when I decide what to do with the mid-bass driver.
@hitsware thanks for helping me with the nomenclature. The speaker building business has its own language and so much to learn.
Thank you all!
@motokoc thanks for the suggested candidates. I will check each out. The tweeter is not within a cabinet at all - it is essentially glued upright in the same plane as the mid-bass driver. Playing with the cabinet, its stuffing and port, is a good idea but it would be much better if I could do so with many drivers to experiment with. Too bad that's not the case for me. I will try it when I decide what to do with the mid-bass driver.
@hitsware thanks for helping me with the nomenclature. The speaker building business has its own language and so much to learn.
Thank you all!
Re tweeter location; ideally we want the VC's to line up vertically in a side view to 'time align' wire them all positive polarity, i.e. where the magnet joint is close enough.
I'm not sure I understand. Let me take a shot at what I think you mean... Looking from the side, with drivers firing 90 degrees from the direction to which my nose would point, you want the magnets of the coils to line up to control the phase. Am I close?
Close if I follow; i.e. ideally we want the tweeters at whatever height lines up with our ears or at some average if family, dance/whatever oriented, otherwise will need to 'steer' the polar response with the XO design.
Where the magnets line up is ideally measured and Altec lined up the midpoints of each magnet (pg 4) as very close to their driver designs, but most folks line up where the magnet mounts to the frame as plenty close enough.
Where the magnets line up is ideally measured and Altec lined up the midpoints of each magnet (pg 4) as very close to their driver designs, but most folks line up where the magnet mounts to the frame as plenty close enough.
I don't yet have the parts to do an RTA with the polarity of the tweeter reversed, but I think I understand. It sounds easy and a very correct way to go about phase alignment. Since I expect the crossover to take place when the mid-bass driver is about 34 degrees out of phase at 2 KHz, I was planning to use a Linkwitz 4th order crossover to help. Any thoughts about this being a good idea or not?
The time-alignment with your tweeter panel in the z-axis is one thing, but so is the vertical distance between the tweeter and woofer; unusually high in this cabinet compared to most designs. Look into the center-to-center spacing topic and also have a thought about vertical lobing depending on the crossover filter. https://www.diyaudio.com/community/threads/vituixcad.307910/page-139#post-6541438
https://www.ranecommercial.com/legacy/note160.html
https://www.ranecommercial.com/legacy/note160.html
@motokok Thank you for the very good article. It's going to take me a while to digest it and, consequently, to understand vertical distance / lobing problem you're referring to. My tweeter and mid-bass driver are 7.5" (190mm) center to center. That doesn't seem very far, but then I'm not experienced in these things.
My current thinking for parts: Dayton SIG180-4 mid-bass, and Wavecor TW030WA06 tweeter (both are 4 ohms). I may need to seal the port to keep tight bass with the Dayton. I planned to use a Linkwitz-Riley 4th order crossover, but then I really would like to simulate the combination to know more. I have found nothing I can run on my Mac that looks likely to help me. Suggestions?
My current thinking for parts: Dayton SIG180-4 mid-bass, and Wavecor TW030WA06 tweeter (both are 4 ohms). I may need to seal the port to keep tight bass with the Dayton. I planned to use a Linkwitz-Riley 4th order crossover, but then I really would like to simulate the combination to know more. I have found nothing I can run on my Mac that looks likely to help me. Suggestions?
If you get a measurement mic, you can reverse engineer it. Measure the woofers without a x-over to get an idea what your replacement woofer might need to be. Measure it with a x-over to establish a target response. If it currently is crossed at 2k, then look for a tweeter capable of that. Are the tweeters broken?
I do have a measurement mic and can do RTA, FFT, SPL, and a few other things. The tweeters probably aren't broken but the speakers sound bad enough I'm not so sure. The drivers are all 30 years old. I'm not going to gamble with putting the speakers back together with any old rubber. I put together a plan of all the measurements I need to make and include your reverse engineering idea. Thanks.
I have 40 year old Morel tweeters still going strong!
I've seen those speakers before I think. What are they?
This and the Signature drivers are 4ohm. This Buyout appears to have come off the same assembly line.
Peerless HDS drivers use the same basket, but may be hard, or impossible to get new.
https://www.parts-express.com/6.5-Aluminum-Cone-Woofer-Truncated-Frame-80W-4-Ohm-299-2129?quantity=1
I've seen those speakers before I think. What are they?
This and the Signature drivers are 4ohm. This Buyout appears to have come off the same assembly line.
Peerless HDS drivers use the same basket, but may be hard, or impossible to get new.
https://www.parts-express.com/6.5-Aluminum-Cone-Woofer-Truncated-Frame-80W-4-Ohm-299-2129?quantity=1
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