Hi I have a pair iof these old 15" Nakamichi car subwoofer drivers.
I would like thoughts on if they are useful as Subs in a HT & music system?
What enclosure type you would go for?
My priorities are
- clean tight bass rather than necessarily getting 20hz
- smallest reasonable foot print and high sensitivity as they will be pairing with high sensitivity mains.
I have an electronic crossover with variable gain so can match them and am considering shelling out for a miniDSP.
Cabinet making is a hobby so a horn is not out of the question so long as its not a wardrobe sized monster.
I would like thoughts on if they are useful as Subs in a HT & music system?
What enclosure type you would go for?
My priorities are
- clean tight bass rather than necessarily getting 20hz
- smallest reasonable foot print and high sensitivity as they will be pairing with high sensitivity mains.
I have an electronic crossover with variable gain so can match them and am considering shelling out for a miniDSP.
Cabinet making is a hobby so a horn is not out of the question so long as its not a wardrobe sized monster.
- Resistance: 3.2 Ohms
- Frequency Response: 32 Hz
- BL: 17.71
- Mechanical Q (Qms): 4.57
- Electrical Q (Qes): 0.5431
- Total Speaker Q (Qts): 0.531
- SPL: 90dB @ 1W/M
- VAS: 90.579 Ltrs
- X-Max: 18.5mm one way (37mm Total Linear movement)
- Voice Coil: 4 inch Aluminium (black anodised) former 4 Layer winding with thermal coating
- Cone: Bi Laminate combination Paper Pulp with woven Fibre
- https://www.elite-electronics.com.a...xW_Vs7CAirwwgUQiUM4VrXX4cpeWfSpkhfiqCWh-Lhwm2
Looks like a decent driver. The specs aren't consistent though - with the quoted Qms and Qes, Qts should work out to 0.49, not 0.53.
I'd suggest measuring them if you can.
I did a little modeling using the quoted Qes and Qms, and a damped 160 L OD-TL tuned to 26 Hz looks interesting ...
I'd suggest measuring them if you can.
I did a little modeling using the quoted Qes and Qms, and a damped 160 L OD-TL tuned to 26 Hz looks interesting ...
Paper cones or something else? \Personally I'd prefer a lower Fs than 30Hz but that's pretty good movement. Wild though about TLs; do you have enough room in the corners for a SonoSub?
Hi, these speakers require relatively big box but can give you good results.
I would go with ported enclosure for sure, tuned around 25Hz.
See options below. I used just the Qes and Qms and let WinISD calculate Qts, which matched what Brian mentioned (0.485).
Using 80 liters tuned at 25Hz, you get a decent frequency response.
Although 30Hz crosses at -4.5dB, the rolloff slope is smooth around 8dB/oct, so you still have good response below 30Hz.
With 15" speaker, you can easily compensate with eq to boost frequencies below 30Hz and still get flat response down to 20's something Hz.
Above 30Hz, you'll get a good group delay below 12ms.
It will produce a tight bass since the tuning frequency is way below the main music bass range.
On the other hand, if you have more space and willing to have a more extended bass, with 120 liters tuned at 25Hz, you get a super low 27Hz @ -3dB.
It's basically flat from 30Hz (-2dB) and up.
And if you have a lot of space, you'd get a superb frequency response down to 22Hz @ -3dB using 190 liters tuned to 25Hz.
I would go with ported enclosure for sure, tuned around 25Hz.
See options below. I used just the Qes and Qms and let WinISD calculate Qts, which matched what Brian mentioned (0.485).
Using 80 liters tuned at 25Hz, you get a decent frequency response.
Although 30Hz crosses at -4.5dB, the rolloff slope is smooth around 8dB/oct, so you still have good response below 30Hz.
With 15" speaker, you can easily compensate with eq to boost frequencies below 30Hz and still get flat response down to 20's something Hz.
Above 30Hz, you'll get a good group delay below 12ms.
It will produce a tight bass since the tuning frequency is way below the main music bass range.
On the other hand, if you have more space and willing to have a more extended bass, with 120 liters tuned at 25Hz, you get a super low 27Hz @ -3dB.
It's basically flat from 30Hz (-2dB) and up.
And if you have a lot of space, you'd get a superb frequency response down to 22Hz @ -3dB using 190 liters tuned to 25Hz.
Interesting. Thanks for your replies. I don't yet have skills to measure drivers.
I will Google a SonoSub, I know nothing of them. I am interested in building Transmission lines if I can keep the size manageable.
Lots off cleaning needed.
I will Google a SonoSub, I know nothing of them. I am interested in building Transmission lines if I can keep the size manageable.
Lots off cleaning needed.
Thanks Ron, that 190 litre cabinet looks the business. I have another thought, how about putting the pair of them in a 95 litre box in an Isobaric arrangement? as a way of reducing the box size.
If a plate amplifier with some DSP capability is being used, another option is a 190-litre vented-box enclosure tuned to 20.0Hz. The simulated response when a VituixCAD-HP shelf filter is used together with a Linkwitz–Riley low-pass filter is shown below. Here we have an F3 = 17.1Hz, which is about 5Hz lower than the non-EQed version in the same size enclosure.
The watts required and the attendant cone travel range were shown in the simulation. The cone travel isn't all that high, but in the end that's likely to be a bit of a problem. That's because the alignment has maximum power consumption at the point of minimum cone travel, approximately 21Hz, which may cause problems with heat dissipation. Of course, the simulation has assumed values of enclosure losses QL and QA, and may not be predicting the cone excursion near port resonance particularly accurately.
For comparison, the standard 190-litre vented-box enclosure tuned to 25Hz produces the following results when a Linkwitz–Riley low-pass filter is included in the simulation. For this system the −3dB low-frequency cut-off point is estimated to be F3 = 23.1Hz.
For comparison, the standard 190-litre vented-box enclosure tuned to 25Hz produces the following results when a Linkwitz–Riley low-pass filter is included in the simulation. For this system the −3dB low-frequency cut-off point is estimated to be F3 = 23.1Hz.
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Hi! Yes, you can use 90 liters with one pair of woofers in iso-barik mode and have a similar result as the 190-Liter using a single woofer.
This is just simulation - I only have experience with single woofer speakers and, with single woofers, WinISD has given good results when comparing simulation and the real builds. So, I suppose the iso-barik will produce similar results.
Looks like these might work.
As it happens I have some enclosures that I just measured. They are 142 litres but need some bracing added so will realistically be about 140l minus the capacity of the driver once installed.
They have a slot port 40mmx500mm that is 500 long.
I am not sure how these model. I have a pair of them that can easily be bought into service. The two would be a bit larger than I would like in the room but if they work really well might be worth accomodating. Or I could mount the pair in one box isobarik mounted.
ron68 do you mind running those dimension through your software and see how that port looks? It calculates as 200cm2 so a bit bigger than a 6" pipe port.
Thoughts?
As it happens I have some enclosures that I just measured. They are 142 litres but need some bracing added so will realistically be about 140l minus the capacity of the driver once installed.
They have a slot port 40mmx500mm that is 500 long.
I am not sure how these model. I have a pair of them that can easily be bought into service. The two would be a bit larger than I would like in the room but if they work really well might be worth accomodating. Or I could mount the pair in one box isobarik mounted.
ron68 do you mind running those dimension through your software and see how that port looks? It calculates as 200cm2 so a bit bigger than a 6" pipe port.
Thoughts?
I prefer stereo subs myself unless I have room for more and I'm also a firm believer in using what is already available
Hi!
If your box has 142 liters gross, let's suppose 120 liters net - we have to discount the bracing, the port volume (in this case external cause I suppose it is made with wood) and the woofer space, The port net volume is 10liters plus 5 liters of the wall, supposing 20mm thick. You can measure all and tell me exactly what net volume you estimate. It won't change much the result anyways.
If we consider 130 liters instead of 120 tuning frequency drops 1Hz only - pratically no difference.
With 120 liters net, you get a very good result even with a single woofer per box.
So, if you have a pair of boxes and a pair of speakers, you can build 2 subwoofers, which is much better as already mentioned - stereo subs!
Easy to build since it's ready.
You'd get FR down to 26Hz @-3dB - The tunning frequency would be 28.3Hz
If your box has 142 liters gross, let's suppose 120 liters net - we have to discount the bracing, the port volume (in this case external cause I suppose it is made with wood) and the woofer space, The port net volume is 10liters plus 5 liters of the wall, supposing 20mm thick. You can measure all and tell me exactly what net volume you estimate. It won't change much the result anyways.
If we consider 130 liters instead of 120 tuning frequency drops 1Hz only - pratically no difference.
With 120 liters net, you get a very good result even with a single woofer per box.
So, if you have a pair of boxes and a pair of speakers, you can build 2 subwoofers, which is much better as already mentioned - stereo subs!
Easy to build since it's ready.
You'd get FR down to 26Hz @-3dB - The tunning frequency would be 28.3Hz
And how low with room gain?
-3dB at 26Hz would be enough for me most times.
Worth exploring a large sealed box with DSP also, assuming you wanted to go that direction.
A slot port is easily sealed or stuffed
-3dB at 26Hz would be enough for me most times.
Worth exploring a large sealed box with DSP also, assuming you wanted to go that direction.
A slot port is easily sealed or stuffed
Thanks heaps ron68. It models well. Looks like my intended crossover of about 100hz is very safe and will plumb all the depths I need. I have two of these boxes. They are made from 25mm mdf and very solid but zero bracing in them and they are a bit square for ideal. I think I will get them in the shed and put some bracing in them and try to break up the dimensions with some offset bracing. I will report back...
In the screenshot that was provided, a slotted port was being used. Is the "0.732" end correction the appropriate one to be used for this condition?
Can you explain the end correction? What does the number mean is it like a round over diameter or something?
Depending on how the ends of the vent are flanged, there is a correction term in the formula that is used to compute the vent length. The diagram below shows how different vent arrangements change the end correction, k. The end correction term reduces the computed physical length of the port, and the k value affects how great this reduction will be.
Thanks Witwald.
This explanation tells me my slot port is incorrect.
It would have a k value of 2.27 as the entire back wall of the enclosure is a slot ie the slot is the 500mm height of the cabinet by a 40mm gap from the rear wall of the cabinet. So the 'slot ' is 500mm wide x 40mm with length of 500mm.
The internal entrance to the slot is also 40mm opening into the slot. Maybe I should block the slot and bore a 150mm hole for some 6" pic water pipe at water ever length the calculator suggests.
This explanation tells me my slot port is incorrect.
It would have a k value of 2.27 as the entire back wall of the enclosure is a slot ie the slot is the 500mm height of the cabinet by a 40mm gap from the rear wall of the cabinet. So the 'slot ' is 500mm wide x 40mm with length of 500mm.
The internal entrance to the slot is also 40mm opening into the slot. Maybe I should block the slot and bore a 150mm hole for some 6" pic water pipe at water ever length the calculator suggests.