testing midrange/bass drivers without enclosure

patchwork · 8th February 2007, 03:18 AM

I bought a couple of pairs of used drivers, and I'd like to test them to make sure they work.

Could I just connect them to an amplifier, without crossover or enclose, and play some music through them at a low volume just to see if they play, or could this cause damage? I doubt it would, but just checking.

I would ask the same about tweeters, but someone told me absolutely not to do this.

thanks for the replies

sek · 8th February 2007, 02:30 PM

You can safely connect an amp to a mid/bass speaker in free air. Just watch the amplitude. If the units are halfway decent, they won't even damage from pushing to the mechanical limit, but take care.

Never do this to a tweeter, though, that's right. It would rip up from the force the unfiltered low frequency energy would impose on the voice coil. If it doesn't break, it will burn from overheating. One of the two.

Cheers,
Sebastian.

PS: Professional speakers are 'warmed up' and tested in free air, as only this way the spider/suspension can settle and get tested without horrible noise.

patchwork · 8th February 2007, 03:12 PM

sek, thanks very much for the reply.

I'll try them out this weekend.

Cal Weldon · 8th February 2007, 04:08 PM

Patch,

Do you have any capacitors? If so, I would recommend you attach a 20mfd non-polarized to the mid before testing. Then you can turn it up a bit and not have to worry about damage. The reason you want to turn it up is that sometimes the driver will sound good at very low volume but begin to get noisy when turned up. The capacitor will protect the mid from low frequencies.

The woofer is fine on it's own.

What drivers do you have? Can you post a pic or two?

patchwork · 8th February 2007, 05:31 PM

I have:

HiVi F5
Vifa PL14
Vifa M18 (discontinued model, similar to PL18)
ScanSpeak 13m/8640

I do think all can be used as the midrange / bass driver in a 2 way config.

Geoff H · 8th February 2007, 10:38 PM

Hi Patchwork, you can get a fairly good idea of how a driver sounds by placing a piece of anything absorbent over the back of the driver, and listening up close to reduce the effect of out of phase energy off the back of the cone.

I do that when treating cones and surrounds, quicker than bolting to a baffle.

And yep, tweeters, and small midrangers should be filtered.

patchwork · 9th February 2007, 03:28 AM

I tried them out. It worked well.

I was shocked at how good the ScanSpeak 13M/8640's sounded on their own, no enclosure. I can't wait to make a 3-way design with them.

8th February 2007, 03:18 AM	#1
patchwork diyAudio Member Join Date: Dec 2006	testing midrange/bass drivers without enclosure I bought a couple of pairs of used drivers, and I'd like to test them to make sure they work. Could I just connect them to an amplifier, without crossover or enclose, and play some music through them at a low volume just to see if they play, or could this cause damage? I doubt it would, but just checking. I would ask the same about tweeters, but someone told me absolutely not to do this. thanks for the replies

8th February 2007, 04:08 PM	#4
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Patch, Do you have any capacitors? If so, I would recommend you attach a 20mfd non-polarized to the mid before testing. Then you can turn it up a bit and not have to worry about damage. The reason you want to turn it up is that sometimes the driver will sound good at very low volume but begin to get noisy when turned up. The capacitor will protect the mid from low frequencies. The woofer is fine on it's own. What drivers do you have? Can you post a pic or two? __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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8th February 2007, 02:30 PM	#2
sek diyAudio Member Join Date: May 2003 Location: Berlin	You can safely connect an amp to a mid/bass speaker in free air. Just watch the amplitude. If the units are halfway decent, they won't even damage from pushing to the mechanical limit, but take care. Never do this to a tweeter, though, that's right. It would rip up from the force the unfiltered low frequency energy would impose on the voice coil. If it doesn't break, it will burn from overheating. One of the two. Cheers, Sebastian. PS: Professional speakers are 'warmed up' and tested in free air, as only this way the spider/suspension can settle and get tested without horrible noise.

8th February 2007, 03:12 PM	#3
patchwork diyAudio Member Join Date: Dec 2006	sek, thanks very much for the reply. I'll try them out this weekend.

8th February 2007, 05:31 PM	#5
patchwork diyAudio Member Join Date: Dec 2006	I have: HiVi F5 Vifa PL14 Vifa M18 (discontinued model, similar to PL18) ScanSpeak 13m/8640 I do think all can be used as the midrange / bass driver in a 2 way config.

8th February 2007, 10:38 PM	#6
Geoff H diyAudio Member Join Date: Oct 2006	Hi Patchwork, you can get a fairly good idea of how a driver sounds by placing a piece of anything absorbent over the back of the driver, and listening up close to reduce the effect of out of phase energy off the back of the cone. I do that when treating cones and surrounds, quicker than bolting to a baffle. And yep, tweeters, and small midrangers should be filtered.

9th February 2007, 03:28 AM	#7
patchwork diyAudio Member Join Date: Dec 2006	I tried them out. It worked well. I was shocked at how good the ScanSpeak 13M/8640's sounded on their own, no enclosure. I can't wait to make a 3-way design with them.

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