Help for DIY speakers

[Researchrob]

Hi everyone, i have just joined the community.
I've been reading alot from previous from other 3Ds but i'd like to have your help:

So i am approaching DIY speaker and i have decided to go 4ohm 1 TW and 2 Woofers as follow:

D2904/710003 - Tweeter 25mm Scan Speak - Revelator - 4ohm:
D2904/710003 - Tweeter 25mm Scan Speak - Revelator - 4ohm — Tweeter | Axiomedia

Scanspeak Ellipticor 21WE/4542T-00, 8" Mid-Woofer, 4 ohm
Scanspeak Ellipticor 21WE/4542T-00, 8" Mid-Woofer, 4 ohm

22W/4851T00 - 8" Woofer Scan Speak - Revelator - 4ohm
22W/4851T00 - 8" Woofer Scan Speak - Revelator - 4ohm — Woofer | Axiomedia


First i thought to go with 3-way crossover than i've read about 2.5 way crossover. Now since i'm not capable of building acossover. I kindly ask if i can use a 2-way crossover and a passband

Is it possible to combine this 2 way crossover at 1600hz:
Eminence PXB2:1K6 2-Way Speaker Crossover Board 1,600 Hz

And a low pass crossover at 250Hz?
Eminence PXB:250 Low Pass Crossover Board 250 Hz

If above is possible can you explain how to wire?

Thanks in advance for your advice

Best

 

[Galu]

Hello and welcome to the forum!

Your thread would be best transferred to the 'Loudspeakers, Multi-Way' section of the forum.

 

[Galu]

That's quite an outlay of money for the drivers (one woofer alone costs almost £300).

Off the shelf Eminence crossovers are not the way to go as they cannot possibly match with, and do justice to, your Scanspeak drivers.

I'm afraid you need crossovers which are specifically designed for your combination of drivers. If you can solder, you can build them!

Hopefully, the crossover design experts will chime in with suggestions.

Would you clarify your design intentions - tweeter, mid/woofer and woofer all in one cabinet or what?

 

[Tweet]

Researchrob, it is the crossover that will make or break a loudspeaker's listenability, not necessarily the quality of drivers themselves regardless of their price.


With low impedance drivers such as these with their low distortion attributes it will be an expensive exercise in quality components for the crossovers.


For inexperienced DIY'ers it can be a disappointing outcome particularly if they have spent a large sum of cash on a design, only then to find it does not perform to their expectations.


Loudspeaker design requires a knowledge base to be successful, that's why we are here ..... to learn from one another's experience. It's a great resource. If you haven't already outlayed all that expense for the drivers yet I would suggest you try something more reasonably priced and at a higher impedance.


Welcome to the forum, and you'll also find not everyone is as forward as myself.


C.M

 

[Researchrob]

Nope unfortunately i have already ordered the drivers, the thing is i would have gone 3 way but i feel stucked and as you mentioned, and have a little bit of fear of breaking up something.

My second option will be to use a 2-way crossover maybe wiring in series the two woofers 2DF1800 - PRV Audio

 

[picowallspeaker]

Hi Rob, why have you decided to go 4 Ω ?
About the -research in your nick, you seem to have not made some...
(8 Ω is better for the amplifier).
Why didn't you ask Axiomedia? Oh, they just sell...

About the drivers that you chose, I'd prefer a true 3-way design- so a real midrange might be needed, and that would make the design more easy ( for the ears )
So, you select a speaker between the two 8", then you have to select a suitable driver for the midrange >>> OH NO! I'm falling in the step-by-step-How-to-start-with-LS-design_basics

 

[YSDR]

These sepaker with that driver combination needs to be a 3 way, because if you connect the woofers for 2 or 2.5 way the impedance would dip below 2 Ohm easily. You can't use series connection for nominal 8 Ohm total because the woofers are not identical.
Even with 3 way, the impedance probably dips below 3 Ohm, but that's much better then say 1.5 Ohm with a 2.5 way.

 

[AllenB]

maybe wiring in series the two woofers

Probably not a good choice. They are not likely to play evenly together. Although it can be done it would be random and unusual.

2.5 way crossover.

This was the first thing that I thought would work, however there is a sensitivity difference between the drivers of 4.5dB, so no.

This leaves two-way using one of the woofers per side.

 

[system7]

Researchrob, I think you may have got extremely lucky here in choosing two almost identical 8" 4 ohm drivers!

Wire them in series in a biggish 60 litre box, and they come out at 8 ohms and around 93dB loudness.

Unfortunately they appear to go to Hell above 1kHz.

Scanspeak Ellipticor 21WE/4542T-00, 8" Mid-Woofer, 4 ohm

I doubt if this is doable as a two way with any 1" tweeter I can think of. I think you need a midrange at this point to get it working:

SEAS-3-Way-Classic

 

[voodooless]

Put the tweeter on a waveguide to boost the low end a bit so you can lower the crossover point to the massive 8" "mid" as close to 1Khz as possible. Next go active, at least two channel, so you can integrate the second 8" properly. And at the bare minimum get yourself a measurement microphone.

 

[mbrennwa]

It seems to me you want to read this: So you want to design your own speaker from scratch!

It's good advice.

 

[Researchrob]

Hi Rob, why have you decided to go 4 Ω ?
About the -research in your nick, you seem to have not made some...
(8 Ω is better for the amplifier).
Why didn't you ask Axiomedia? Oh, they just sell...

About the drivers that you chose, I'd prefer a true 3-way design- so a real midrange might be needed, and that would make the design more easy ( for the ears )
So, you select a speaker between the two 8", then you have to select a suitable driver for the midrange >>> OH NO! I'm falling in the step-by-step-How-to-start-with-LS-design_basics

To me was ok to match the 4 Ω when i've selected the drivers as i have a tube amp with 4ohm output.

I understand the 3-way which was my first tought during the selection but as i came across the 2.5 way crossover i tought it could be an option, which as far as i read is not feasible as the two 8" because "can't use series connection for nominal 8 Ohm total because the woofers are not identical".

I know also that cabinet will influence in crossover build for Fq response but again this 3D is to have your feedback which are quite resolving so far.

But again asking for people feedback and ideas it's really helpful

So thanks for all your shares so far

 

[voodooless]

The second 8" won't be happy with a tube amp. To get to the low end extension, you'll need quite a bit of power.

I'd stick it in a separate subwoofer box and additional higher power amplifier. That then leaves only a 2-way to design, which should be quite a bit easier. Looking at these measurements, it looks better than the datasheet. There might be some hope yet.

 

[Researchrob]

To me was ok to match the 4 Ω when i've selected the drivers as i have a tube amp with 4ohm output.

I understand the 3-way which was my first tought during the selection but as i came across the 2.5 way crossover i tought it could be an option, which as far as i read is not feasible as the two 8" because "can't use series connection for nominal 8 Ohm total because the woofers are not identical".

I know also that cabinet will influence in crossover build for Fq response but again this 3D is to have your feedback which are quite resolving so far.

But again asking for people feedback and ideas it's really helpful

So thanks for all your shares so far

I should be able to power it, i have 200 watts per channel continuous from 20Hz to 20kHz. Approximate actual power available at "clipping" 230 watts (1kHz).

I assume i can go 3-way if 2.5 not feasible at this point

 

[voodooless]

I assume i can go 3-way if 2.5 not feasible at this point

Even if you have the power available, the efficiency of the second 8" will not match up to the rest of the system. Getting everything driven from one amp/channel is not a good idea.

Are you sure the amp is purely a tube amp? I'm betting it's a hybrid with a tube input or gain stage..

 

[beardman]

Those SS driver is really good...specially the Elipticor...it sound great

but it is a big shame with so fine driver not to make the Crossover right..it is not easy to make filter without measure in the finished box you make,,,


do you know someone near you ,,who can measure,,,

if you just try to make filter ,without to measure,,,it can sound ok,,,,but it is a hard way to go
if i have to chose crossover frequency i will say

100hz to woofer and 1800hz to tweeter

link to TG .. 21WE-4542-T00_test

and here you can calculate filter.... HiFi Loudspeaker Design

 

[Researchrob]

Even if you have the power available, the efficiency of the second 8" will not match up to the rest of the system. Getting everything driven from one amp/channel is not a good idea.

Are you sure the amp is purely a tube amp? I'm betting it's a hybrid with a tube input or gain stage..

I have following mono
ARCDB - VM220

 

[Researchrob]

Those SS driver is really good...specially the Elipticor...it sound great

but it is a big shame with so fine driver not to make the Crossover right..it is not easy to make filter without measure in the finished box you make,,,


do you know someone near you ,,who can measure,,,

if you just try to make filter ,without to measure,,,it can sound ok,,,,but it is a hard way to go
if i have to chose crossover frequency i will say

100hz to woofer and 1800hz to tweeter

link to TG .. 21WE-4542-T00_test

and here you can calculate filter.... HiFi Loudspeaker Design

Thank you so much will look at it

 

[wolf_teeth]

Due to the sensitivity mismatch, a 2-way on your 8" and tweeter and a plate or second power amp on the woofers makes sense. Otherwise you lose all of that sensitivity padding the mid to meet the woofer with resistance.

Later,
Wolf

 

[beardman]

It is not easy to get those unit to play together ,look at this speaker from Troels G

it can be used with Hypex or passive filter for the woofer (i use it passive ,sound better)

The-Loudspeaker

but ,,the impedance on this speaker goes low to about 3ohm,,,(unit are 8ohm)

same could happen with the Scanspeak driver,,,therefor it is a good idear to measure the impedance,,with the crossover

the midrange driver in my speaker use resistor to lower sensitive,,so it can be done

but it is right,,the best way to go is with a Hypex ,,,wil also be a little easier to make filter
then