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Help me convert old speakers to actives

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AlmaAtaKZ

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I just try to protect him from another-half decent built and thrown away money.
I mean ok,it's his money,he can burn them if he like.Fine with me.

I'm all in for starting fresh though,scrap this and have all the fun in the world building new ones.
Would be nice to have a full build - new cabinet, new drivers, powerful amps etc, but I do not have a workshop or even much physical space for woodwork or tools. But it still may come one day.
 
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AlmaAtaKZ

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I did some reading,yes.
My objection is not about the built but about the speaker as it was new,as if it would buy it right now.
Would it's measurements be decent?Modeling would show that since we don't have any other data.

Then,maybe it would worth replicating the x-over or even improve it.
But without data at hand it's a shot in the dark.
I do not see (maybe wrongly) the need to replicate the passive crossover. The route of measuring each driver and then making DSP crossover accordingly seems logical and sufficient to me. Why would I need to go another route? Is there a route which would give a better result?
 
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AlmaAtaKZ

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Hypex plate amps do not need ... anything but mains power .... at least with stereo ...
Given the limiters and controls available in Hypex I am happy to take the risk of frying the existing drivers.
 
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AlmaAtaKZ

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All points discussed before.
The shot in the dark would be enlightend with an image of the crossover, plan of enclosure and measurement of drivers FR.
After that we go on ....
the first two (crossover pic and enclosure config) I can do this weekend.
driver measurements not sure. One way is to use the Hypex amps (which I do not have yet). I could use another amp, right? I have an AVR, so I can send the test signals (from REW? from Hypex filter design software?) to the AVR and connect one amp channel output to the driver. I also need the Umik for this.
- is it better to leave the driver during this measuring in the enclosure or remove it and measure in free air?
 
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AlmaAtaKZ

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Some comments.

1. Don't get a USB mic. If you must get a USB mic, get a UMIK-2. The reason: unreliable timing information due to different clocks between the ADC on the mic and DAC. John Mulcahy (author of REW) tested a few mics here. In addition, the Audiolense user forum is full of complaints from users who use USB mics. A 48V Phantom power mic with an interface is much better. Someone suggested a Focusrite 2i2, but I would suggest that you get an interface with as many DAC channels as drivers that you need to control. In your case, 6. Something like an RME Fireface UC/UCX, Motu Ultralite Mk.5, Merging Anubis, or its Neumann clone (I forget what it's called).

2. Choice of DSP. You can choose either hardware (MiniDSP, DSPNexus, etc) or software. You are limited to software that can actually generate crossovers, which means Acourate, Audiolense, REW, DRC-FIR, Eclipse Audio FIR Designer, etc. PC based DSP is vastly more powerful, both in terms of processing power and the fine corrections that can be done. Hardware DSP is more robust and more convenient.

3. Choice of XO points and slopes. Measure your drivers and look for distortion and anomalies in the output. Decide if you want to deal with it, and how. For e.g. cabinet resonances can be dealt with through physical means, which is the proper way. The lazy way is to notch them out with DSP or remove them with a crossover so you don't have to worry about them :)

Good luck!! It's a fun journey. I had tonnes of fun doing exactly what you are proposing.
OK, looks like I need to go for Umik 2. So, budget increase to 295GBP e.g. here: https://strictlystereo.com/product/minidsp-umik-2-usb-microphone/
 
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Sokel

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I do not see (maybe wrongly) the need to replicate the passive crossover. The route of measuring each driver and then making DSP crossover accordingly seems logical and sufficient to me. Why would I need to go another route? Is there a route which would give a better result?
Replicating the existing crossover is your chance to at least let the drivers operate in their useful (and safe) range.
It's also a good starting point,at least for lows as the cabinet+drivers are made to work for these dimensions.

That's why some other members ask for a photo of the crossover,so we can see the slopes,cutting points,BSC,etc.
Make sure you take a photo from both sides if possible if there are connections underneath.
 
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AlmaAtaKZ

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Replicating the existing crossover is your chance to at least let the drivers operate in their useful (and safe) range.
But I would achieve the same by measuring the drivers. I understand I can model, but I do not see why I need to model.
 

Purité Audio

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Do you hope to improve the sq of the speakers or is mainly just an interesting project?
Keith
 

Sokel

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But I would achieve the same by measuring the drivers. I understand I can model, but I do not see why I need to model.
You will then only know your driver's parameters and you will still have to model the cabinet+drivers (of course way easier since you'll have the data at hand) if you want to modify the existing.
 

Sokel

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Mainly a learning project.
Since your intention is learning,take a look at a very interesting thread about speaker measurement and modeling.
VituixCad is free,covers all aspects and you can learn a lot just by reading it's instructions and using it.


 
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AlmaAtaKZ

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drivers out:

the tweeter is the only marked driver. the two others appear identical and have no markings.
the whole chamber behind all three drivers is a single volume. there is a separate chamber at the bottom (filled with sand), it is about 18cm tall

tweeter

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr
 
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AlmaAtaKZ

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the crossover

the wires to both midwoofers originate at the same points of the crossover (and both drivers are in the same chambre), so this means it is a 2-way, with both midwoofers playing MF and LF, right?

a few slightly different angles of view

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr

Untitled by AlmaAtaKZ, on Flickr
 

Salt

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So a simple 2-way BR with 12 dB crossover (probably at 2 1/2 kHz as usual).
 
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