As title .
I want to use 2 in each side and I want sealed enclosures.
Will be using Morel Tweeter and Mid.
Shame their woofers are all 6”, they’ll look a little lost.
Tang and W8 was an option but they don’t seem to exist anymore. I’d have to import Anarchy’s.
Hopefully I’ve missed some options .
I want to use 2 in each side and I want sealed enclosures.
Will be using Morel Tweeter and Mid.
Shame their woofers are all 6”, they’ll look a little lost.
Tang and W8 was an option but they don’t seem to exist anymore. I’d have to import Anarchy’s.
Hopefully I’ve missed some options .
That's not an easy project. Could be entering a World of Hurt IMO.
Before going into why I think this could be difficult, have you found a similar reputable design to inspire you?
Why 4 ohm bass? Why closed box? Why Morel? These are very limiting choices.
I think the crossover will be difficult, because the woofers will be very loud.
Here's a 92dB Scanspeak 22W/4534G00 reflex driver: Scanspeak 22W/4534G00 Woofer - Discovery Range
Here's more 4 ohm 8" basses most of which will be difficult to source in UK, I'd guess:
Impedance, Nominal Diameter
I just have a bad feeling about this.
Before going into why I think this could be difficult, have you found a similar reputable design to inspire you?
Why 4 ohm bass? Why closed box? Why Morel? These are very limiting choices.
I think the crossover will be difficult, because the woofers will be very loud.
Here's a 92dB Scanspeak 22W/4534G00 reflex driver: Scanspeak 22W/4534G00 Woofer - Discovery Range
Here's more 4 ohm 8" basses most of which will be difficult to source in UK, I'd guess:
Impedance, Nominal Diameter
I just have a bad feeling about this.
4ohm because I want 2, sealed because I want punch and these will be crossed at 80Hz for films, Morel because high power handling.
I have however learned tonight (hence 2am) the 9” Morel is actually 8.5 (well seems to fit in the same basket), had a high Qts and suits sealed enclosures.
I have however learned tonight (hence 2am) the 9” Morel is actually 8.5 (well seems to fit in the same basket), had a high Qts and suits sealed enclosures.
Reason I asked if you have seen a similar reputable design to adjust to taste is there are a lot of problems with a speaker of this complexity. Impedance is the worst.
Happily Curt Campbell and Jim Holtz have done stuff on these lines, along with the late Dennis Murphy:
Speaker Design Works
Plenty to go on there. Series wired MTM has some advantages on impedance and maybe easier than parallel wired:
Tritrix_pg_1
I don't see why you couldn't venture into the sort of territory of the huge Statements and derivatives:
Statements
The metal Dayton RS225-8 gets away with a lot because it is a lowish 86.5dB driver:
Dayton Audio RS225-8 8" Reference Woofer
The 91dB RS225-4 looks doable series wired:
Dayton Audio RS225-4 8" Reference Woofer 4 Ohm
Very efficient mids and tweeters keep impedance up. Usually you prefer a flattish mid.
Happily Curt Campbell and Jim Holtz have done stuff on these lines, along with the late Dennis Murphy:
Speaker Design Works
Plenty to go on there. Series wired MTM has some advantages on impedance and maybe easier than parallel wired:
Tritrix_pg_1
I don't see why you couldn't venture into the sort of territory of the huge Statements and derivatives:
Statements
The metal Dayton RS225-8 gets away with a lot because it is a lowish 86.5dB driver:
Dayton Audio RS225-8 8" Reference Woofer
The 91dB RS225-4 looks doable series wired:
Dayton Audio RS225-4 8" Reference Woofer 4 Ohm
Very efficient mids and tweeters keep impedance up. Usually you prefer a flattish mid.
Thanks for the details on the Dayton.
It's actually the same size as the Morel 9" (in fact 1mm bigger) but the 91db on the 4ohm is great.
Time for more PCD time.
You going to wire them in series? If you were going to parallel (to get the efficiency gain) you would want to go 8 ohms, unless you have a 2 ohm capable amplifier....
Tony.
hmm are they both stated at 1M / 2.83V? Also I need to double check on the efficiency calcs... wiring two in series I think you will drop 3db on that 91db....... I always get this mixed up... 2 paralleled definitely gives you 6db... +3db from the surface area gain, +3db from the 1/2 the impedance.
2 in series I think gives overall the same efficiency, +3db from the surface area, -3db from the doubling of impedance.
I think from memory the advantage that series gives you is half the displacement for the same spl.
But I'm tired and need to go to bed, hopefully if I have just spouted a load of cods wallop someone will jump in and correct it! 🙂
ok looked at the specs and both specified as 1M/2.83V around 4.2db difference in the sensitivity of the 8 ohm, so you would get an advantage of around 1.8db with two parallel 8 ohm drivers, the 8 ohm also has an extra mm of Xmax...
Tony.
2 in series I think gives overall the same efficiency, +3db from the surface area, -3db from the doubling of impedance.
I think from memory the advantage that series gives you is half the displacement for the same spl.
But I'm tired and need to go to bed, hopefully if I have just spouted a load of cods wallop someone will jump in and correct it! 🙂
ok looked at the specs and both specified as 1M/2.83V around 4.2db difference in the sensitivity of the 8 ohm, so you would get an advantage of around 1.8db with two parallel 8 ohm drivers, the 8 ohm also has an extra mm of Xmax...
Tony.
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A woofer does not need to have a high Qts to work in a sealed enclosure. Qts depends on the suspension's compliance which you will stiffen anyway by adding an air spring, when you mount the woofer in a box. The final Qtc which includes the stiffness of the air spring of the enclosure is what counts.
Qts = 0,34 / fs = 30 Hz / Vas = 95 L
In a 30 L closed box it will have Qtc = 0,71 / fc = 64 Hz. Sensitivity is 89,5 dB @ 2 V and it has 70 W power handling.
Agree.
Qts = 0,34 / fs = 30 Hz / Vas = 95 L
In a 30 L closed box it will have Qtc = 0,71 / fc = 64 Hz. Sensitivity is 89,5 dB @ 2 V and it has 70 W power handling.
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I am using this in a 2-way with a SB26ADC in aurgerpro's 8" waveguide.
Not really done with them, but I have done some testing and have some insight on the 4 ohm Scan 22W. I am using the 4 ohm, as these are being used active with Hypex Fusion amps.
The scan 22W is a fine midbass, but as expected, it does have rising 3rd order harmonic starting where you can see the breakup happening on the frequency response chart (where FR starts rising... 950 Hz or so). This provides the main limitation for the speaker... though it's an 8 inch, so you should already be planning on a low-ish XO
- the rising FR does add some complexity to a passive XO. A little less of an issue using it active.
- the 3rd order starts low enough it wasn't really noticeable at a 1400Hz LR4 XO, but who knows how high it can be used for the OP, but few 8" speakers are going to be all that much better able to run out much higher, especially considering directivity / dispersion.
Parallel wiring: impedance halved, sensitivity +6dB (up to)
Series wiring: impedance doubled, sensitivity unchanged
For a series wiring and a 80Hz crossover to a subwoofer I'd use the Dayton Audio RS225P-4A
Ralf
Series wiring: impedance doubled, sensitivity unchanged
For a series wiring and a 80Hz crossover to a subwoofer I'd use the Dayton Audio RS225P-4A
Ralf
THat's what I'm going for but two 8Ohms keeps ending up with a system impedence less than 3Ohms sometimes 2ohms.
Seems 2 x 4 Ohm in series works ok. My next lesson is about phase. There's a lot more to learn than I imagined when I started this.
Seems 2 x 4 Ohm in series works ok. My next lesson is about phase. There's a lot more to learn than I imagined when I started this.
An externally hosted image should be here but it was not working when we last tested it.
With two 8 ohm woofers it should be possible to keep the impedance above 3.5 ohms, except at frequencies way below fc, at which it can be 3 ohms. If the minimum impedance at frequencies > 50 Hz is 2 ohms, then something is wrong with the crossover.
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I’m using the frd and zma files from Dayton and it kept going below 3ohms.
Only way was to add a resistor in series which doesn’t seem like a good thing?
I did think you would run into problems with this one! 😀
Very efficient basses take away all your wiggle room on crossovers, so you struggle with low impedance.
SP38/13
Visaton-Monacor 2 way sealed simple loudspeaker build plans
I tried Lojzek's likeable but less loud Visaton WS 17E 4 ohm 6" bass with a Troels circuit. All works much better.
If drivers don't play nicely together, it can be a plan to re-evaluate things. Then it all falls into place.
Very efficient basses take away all your wiggle room on crossovers, so you struggle with low impedance.
SP38/13
Visaton-Monacor 2 way sealed simple loudspeaker build plans
I tried Lojzek's likeable but less loud Visaton WS 17E 4 ohm 6" bass with a Troels circuit. All works much better.
If drivers don't play nicely together, it can be a plan to re-evaluate things. Then it all falls into place.
Attachments
Faital Pro 8FE200, since you're in the UK they're 26£ each at Bluearan.
Faital Pro : Faital Pro 8FE200 8 Ohm Faston :: PS26.16 IN STOCK (27 Feb 2021)
That's got a series resistor - is that "acceptable" in crossover design? I assumed it wasn't but it certainly solves the problem.