Hi, I have a nice cabinet of a very closely spaced MTM. Stock drivers are ok but deep bass somewhat lacking for size of cabinet. The woofers aren't really designed for it like a more modern driver. A warm but "woody" kind of sound.
Trying to decide using 2x Mark Audio Pluvia 11s per can either in 1.5 way or 2.5 way with tweeter - or both with crossover switch!
Or, using SB Acoustics 17nac woofers in 2.5 way or mtm and a low Fs tweeter (must be small neo/small flange due to existing arrangement).
How are the Pluvia with bass? Is it worth using them as more of a woofer? They would certainly be the more artistic option as the cabinet is a darkish orangey kind of wood veneer. Roughly 40L.
Drivers need to fit in a 172-3mm rebate if others are to be suggested; slightly smaller can work too
Trying to decide using 2x Mark Audio Pluvia 11s per can either in 1.5 way or 2.5 way with tweeter - or both with crossover switch!
Or, using SB Acoustics 17nac woofers in 2.5 way or mtm and a low Fs tweeter (must be small neo/small flange due to existing arrangement).
How are the Pluvia with bass? Is it worth using them as more of a woofer? They would certainly be the more artistic option as the cabinet is a darkish orangey kind of wood veneer. Roughly 40L.
Drivers need to fit in a 172-3mm rebate if others are to be suggested; slightly smaller can work too
The SB are better woofers, but the Pluvia will be easier to cross higher. So a lot depends on the tweeter used and where you would put the crossover. With the SB i would not go above 2kHz with a typical lower order crossover, while with the pluvia you can go to 3.5kHz i think for a smooth transition as the resonance is much higher and much more damped than the SB.
Rennie,
Without a proper crossover, even if you replace the drivers, it is likely that you will not like the sound...
Running 2 wide-band driver in a 1.5 way config will be simpler; checking the CHP-90 datasheet, the dimensions of the frame indicate that it is 151mm in diameter - smaller that the 172mm rebate you mentioned in your post.
Can you share an image of the cabinet? 40 liters internal volume sounds quite large - it's a floor-stander?
Without a proper crossover, even if you replace the drivers, it is likely that you will not like the sound...
Running 2 wide-band driver in a 1.5 way config will be simpler; checking the CHP-90 datasheet, the dimensions of the frame indicate that it is 151mm in diameter - smaller that the 172mm rebate you mentioned in your post.
Can you share an image of the cabinet? 40 liters internal volume sounds quite large - it's a floor-stander?
172mm fits Mark Audio 11 drivers (or chn110)
It's a floor stander with orangey brown wood.
I'm happy to fiddle around with crossovers trying it out on DSP first.
It's a floor stander with orangey brown wood.
I'm happy to fiddle around with crossovers trying it out on DSP first.
Rennie,
Have you tried DSP with the existing set of drivers?
The cabinet is tall, and the aspect ratio indicates that there will be quarter-wave resonance, but the port is placed much higher. more like a bass-reflex design.
Have you ever taken the drivers out and had a look inside the cabinet? Does the cabinet have any lining on the walls or any stuffing?
Have you tried DSP with the existing set of drivers?
The cabinet is tall, and the aspect ratio indicates that there will be quarter-wave resonance, but the port is placed much higher. more like a bass-reflex design.
Have you ever taken the drivers out and had a look inside the cabinet? Does the cabinet have any lining on the walls or any stuffing?
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It's got cheese hole bracing throughout, foam on walls. I guess it could have extra damping at the bottom if there are pipe resonances. But would have to feed that through at least 2 sets of bracing.
Audax ap170Z0
Vifa bc25
By all accounts is a well built, reasonably nice sounding speaker but it's over 20 years old and there are better woofers out there today. The tweeter is fine for the price of similar bc25 versions.
It's a great cabinet that couldn't be replicated for the price I bought the speakers - definitely also an aesthetic thing; I'd like it to look nice too
Compared to speakers with higher end drivers, this one has hearable bass harmonic distortion
Audax ap170Z0
Vifa bc25
By all accounts is a well built, reasonably nice sounding speaker but it's over 20 years old and there are better woofers out there today. The tweeter is fine for the price of similar bc25 versions.
It's a great cabinet that couldn't be replicated for the price I bought the speakers - definitely also an aesthetic thing; I'd like it to look nice too
Compared to speakers with higher end drivers, this one has hearable bass harmonic distortion
I found a datasheet for the Audax AP170Z0 here:
https://en.toutlehautparleur.com/speaker-audax-ap170z0-6-ohm-6-81-inch.html
Looking at the specs, the CHN-110 is quite close in terms of Qts and Vas.
What I am worried about is the cabinet's effect on the sound; if the port is sub-optimally placed, then there can be unwanted bass resonances (even with the new drivers). Better drivers will not be able to give their optimum performance...
By any chance do you have access to a Dayton DATS device? What is the diameter and length of the port?
https://en.toutlehautparleur.com/speaker-audax-ap170z0-6-ohm-6-81-inch.html
Looking at the specs, the CHN-110 is quite close in terms of Qts and Vas.
What I am worried about is the cabinet's effect on the sound; if the port is sub-optimally placed, then there can be unwanted bass resonances (even with the new drivers). Better drivers will not be able to give their optimum performance...
By any chance do you have access to a Dayton DATS device? What is the diameter and length of the port?
Excellent!
Please also share the impedance measurements of:
1. The speakers with the crossover connected to all the drivers. Basically connect the DATS leads at the terminals and measure.
2. The woofers connected in parallel; assuming you can disconnect the woofers from the XO easily and measure them without XO. Please take pics and/or make necessary markings so that you can reconnect them properly with ease.
Please also share the impedance measurements of:
1. The speakers with the crossover connected to all the drivers. Basically connect the DATS leads at the terminals and measure.
2. The woofers connected in parallel; assuming you can disconnect the woofers from the XO easily and measure them without XO. Please take pics and/or make necessary markings so that you can reconnect them properly with ease.
Cabinet internal estimate
1000mm H
185mm W
250mm D
Port ID : 120mm L, 80mm dia.
Roughly 430mm from bottom
1000mm H
185mm W
250mm D
Port ID : 120mm L, 80mm dia.
Roughly 430mm from bottom
I might have to wait until tomorrow to disconnect woofers; they use solid core cable clamped with u shape and soldered onto terminals. Usually I'd just heat and bend to undo the u shape , but of course these drivers have terminals embedded into the plastic basket directly, and guess what happens when they are hot 🙂
Will need to pull them out and try to hold them with something so I can use both hands.
Here is a pic of the speaker impedance which I've saved. It's very similar for both. I'm guessing that third peak isn't a great thing
Will need to pull them out and try to hold them with something so I can use both hands.
Here is a pic of the speaker impedance which I've saved. It's very similar for both. I'm guessing that third peak isn't a great thing
Attachments
Cab aspect ratio isn't enough to change port position much, just a slight gain, shift higher if vent optimally placed at the bottom (L*0.848, light trace), otherwise ignore the response since it's HR's default driver at optimal L*0.21 single driver offset.
Attachments
GM,
Thank for chiming in.
If I understand correctly, the ideal case would have been placing the port center 152 mm or ~6 inches from the bottom of the cabinet?
From what Rennie has shared the port (center?) is possibly 430 mm or 16.9 inches from the bottom of the cabinet/line.
Thank for chiming in.
If I understand correctly, the ideal case would have been placing the port center 152 mm or ~6 inches from the bottom of the cabinet?
From what Rennie has shared the port (center?) is possibly 430 mm or 16.9 inches from the bottom of the cabinet/line.
You're welcome!
For a round port, yes, otherwise a duct port at the bottom.
Yes, that's what I used for the solid trace.
Note that driver(s), vent(s) ideally need to be at a pipe's odd harmonics, so with 'L' = internal height, 'Z' = driver and using the acoustic center of clustered drivers........
Z = (L)x ~ 0 (top), 0.217, 0.349, 0.424, 0.561
Vent offset only, depending on box HxWxD ratio: Z = (L)x ~0.651, 0.714, 0.848, 0 (bottom)
For a round port, yes, otherwise a duct port at the bottom.
Yes, that's what I used for the solid trace.
Note that driver(s), vent(s) ideally need to be at a pipe's odd harmonics, so with 'L' = internal height, 'Z' = driver and using the acoustic center of clustered drivers........
Z = (L)x ~ 0 (top), 0.217, 0.349, 0.424, 0.561
Vent offset only, depending on box HxWxD ratio: Z = (L)x ~0.651, 0.714, 0.848, 0 (bottom)
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.zma files won't open again in DATS so here is a virtuixcad chart
Below : Whatmough Stock speaker impedance
Below : Audax AP170Z0 Single Free Air
Below : Audax AP170Z0 Parallel 2 Free Air
Below : Whatmough Stock speaker impedance
Below : Audax AP170Z0 Single Free Air
Below : Audax AP170Z0 Parallel 2 Free Air
Just to clarify, the first image is 2 woofers connected in parallel and still installed in the cabinet? Or you have taken the measurement with XO and tweeter connected (guessing this is with XO 🙂)?
The measurement indicates that the Fb is ~40 Hz.
One idea is add a little more Dacron type poly-fill inside the cabinet and see if you can get rid of the third hump. The poly-fill should be well fluffed.
The measurement indicates that the Fb is ~40 Hz.
One idea is add a little more Dacron type poly-fill inside the cabinet and see if you can get rid of the third hump. The poly-fill should be well fluffed.
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Somewhat out of left field, but 6in subwoofer + 6in coaxial will be a much more interesting option. Or 2 (sub)woofers and freestanding horn on top. 6+1+6 just aren't a great match.
Coincidentally, I simulated a similar system in a recent thread: https://www.diyaudio.com/community/threads/2-5-way-crossover-simulation-help.425297/post-7967172
Coincidentally, I simulated a similar system in a recent thread: https://www.diyaudio.com/community/threads/2-5-way-crossover-simulation-help.425297/post-7967172