How to turn Hi-Fi speaker into Guitar speakers ??

[seadi123]

Any simple method to do this ?

[teemuk]

What do you mean... The entire loudspeaker or just its driver?

If you mean the entire loudspeaker you can try removing all high-range drivers and crossover components. Drivers for most guitar applications are usually very high-distortion devices that operate on a narrow bandwidth from circa 100 Hz to maybe 5 - 7 kHz. So practically you are looking for a mid-range driver with not so much care about its linearity, unless you are specifically aiming for very "HiFi" driver selection e.g. Electro-Voice's offerings. At which point you probably wouldn't be asking this question.

Any mid-range HiFi driver will work ok with guitar amps with the typical exceptions:
- It won't be very loud (in comparison to designs specifically aimed for the application)
- It won't be very reliable or long-living (in comparison to designs specifically aimed for the application)

As for driver's internal design... well, you would be entirely rebuilding the thing. HiFi drivers generally aim for great linearity (both distortion and response wise) with the expense of power handling and efficiency. Guitar / PA drivers aim for great efficiency and power handling with the expense of linearity (or at least usually): Voice coils are built to withstand higher currents and temperatures, cone assemblies are built to withstand greater excursions, the entire package is built to produce as much as sound pressure as possible. Basically drivers for guitar amplification are first and foremost built to be loud, robust and to take abuse, when HiFi drivers are designed such parameters aren't a great concern. Then there are of course exceptions like certain Electro-Voice designs which are both loud, reliable and remarkably linear.

[bool]

http://www.electricalaudio.com/phpBB3/viewtopic.php?f=5&t=1994

The Kinks method?

[tca]

^ That also and this.

[tca]

I've played a lot with regular speakers and try to make them useful for guitar. I've tried to use 3'', 5'', 6'', 8'' and last week a cheap 12'' woofer. Cone materials varies from paper, Kevlar, polypropylene and even different cab configurations (closed, open, voigt pipe, and even open baffle).

The kevlar and polypropylene drivers are cheap woofers. The Kevlar (5'') has very stiff bass and strong mids, the polypropylene (8'') driver is more balance, although with to much bass and need to be connected to a high wattage amplifier to really chine.  I prefer this one.

Last week I got a cheap 12'' woofer with 98dB, with frequency range from 50Hz to 3.5kHz (I suspect that the specs are not correct), and build a 57l open cab for it. Works nicely and loud.

I think that all these speakers will have a short average life span when used with a guitar amp, but for practice amps they do the job well, specially if you can build the amp to suit the frequency response of a given speaker.

To cut the story short, get a speaker with the greatest sensitivity you can find (>90db) with a treble cut that works for guitar (<5kHz) and don't neglect the bass roll off.

Look at non-branded 12'' cheap speakers that on-line stores have to offer.

Cheers.

P.S.
To test the speakers get a large piece of wood and cut a hole to accommodate the speaker and make an open baffle cab, this will allow you to test the speakers with out much expense. Something like this:

[Mark Hammer]

I think the challenge is that guitar speakers are always intended to be full-range, while "hi-fi" speakers are normally part of a system that divides the spectrum up into chunks, whether 2, or 3, or even 4 chunks.  There ARE full-range speakers for music reproduction, but they generally don't tend to be bigger than 8", and even when they are nominally full range, they typically have a little tweeter more or less embedded in the middle.

[Hemmel]

Hi guys, haven't posted here in a while.
I'm very interested in this topic since I got the old speakers from my mom's and opened them up.
Inside were 2 InterTan (sub-brand of Tandy -- RadioShack) 12" speakers that I want to convert to a 2x12 cab. Maybe also use either the mid or tweet but I'll have to look into that.
They're all 8 ohms and seem to be in good working order.

I'll need to check their specs though.

[tdkrause]

Teemuk makes a lot of good points. HiFi speakers are meant for a different frequency response than guitar speakers. The guitar amp signal is much more concentrated in the midrange frequencies and can blow a HiFi speaker rated for several times the output of the amplifier. I had a 100 watt plexi years ago. Before I could afford a speaker cabinet, I was running the amp through a 350 watt PA speaker. With the volume on 4, I blew the speaker, tearing the suspension all the way around the speaker. Granted, at 4, even before the amp distorted, there may have been some transients well above 100 watts, but the point is the speaker was not able to handle anywhere near the peak output of that amplifier. My advice when it comes to using a HiFi speaker as a guitar speaker is don't do it. Even if it can handle everything you throw at it, you probably won't be happy with the sound. And FWIF, the sound we like from guitar speakers is actually due to their INEFFICIENCY. Speakers like the EV12L that don't color the tone much are a lot louder than other guitar speakers because they are more efficient, though even the EV12L has some high frequency roll off. Most guitar speakers are much less efficient. Typically, even stereo speakers that are prized for their warm tone like my 1976 Sanyo speakers are fairly inefficient, at least in the higher frequencies.

[tca]

http://www.electricalaudio.com/phpBB3/viewtopic.php?f=5&t=1994

The Kinks method?

[Gus]

Look at the construction of a guitar or bass speaker. 

Note the difference at the surround and look at the spider

A home loud speaker has a controlled signal going to it. 
The music is oftened EQed and limited, one thing this does is reduce subsonics.
CDs etc don't have low frequency rumble like a turntable, LP and room could, ported speakers could move a lot under the system resonate frequency than sealed boxes

The home speaker suspension often relies on a closed enclosure or a ported enclosure that works with the surround and spider to control the speaker movements

A guitar speaker often is in an open back cab and the surround and spider are what control the speaker(the size of the baffle somewhat as well)

So often a home bass speaker will have an excessive movement when being used as a guitar or bass speaker in an open back cab

[Hemmel]

So often a home bass speaker will have an excessive movement when being used as a guitar or bass speaker in an open back cab

How about in a sealed cab ?

[tca]

So often a home bass speaker will have an excessive movement when being used as a guitar or bass speaker in an open back cab

How about in a sealed cab ?

You have to do the math, and ensure that the frequency response is the correct one without damaging the speaker, in particular the max excursion of the cone (Xmax) should not be exceeded.

[Hemmel]

You have to do the math, and ensure that the frequency response is the correct one without damaging the speaker.

I was afraid of that... The speakers I have might not really be suitable for a cab, though...
Impedance : 8 Ohms
Freq resp. : 20 - 2000 Hz
Max wattage : 100 Watts

They look like this one but mine have #40-8414 and the specs I mentioned.
Oh and they also have a few crayon stains courtesy of my niece 

[tca]

You have to do the math, and ensure that the frequency response is the correct one without damaging the speaker.

I was afraid of that... The speakers I have might not really be suitable for a cab, though...
Impedance : 8 Ohms
Freq resp. : 20 - 2000 Hz
Max wattage : 100 Watts

They look like this one but mine have #40-8414 and the specs I mentioned.
Oh and they also have a few crayon stains courtesy of my niece  

I think they will work great in a open cab (57l) powered by some small amp (up to 20W). They will not last "forever" Can you find the specs (T/S parameters)?

[R.G.]

Over the years, there have been a number of questions like this.

They are frequently followed up by wondering where to get replacement hifi speakers after the excess smoke was cleared out of the ones used for the experiment.

One subtlety on hifi speakers is that their power rating assumes the typical 20db peak power to average power ratio in much recorded music. They are often advertised on their peak power handling, but will die with that as a steady diet. "Steady" in this instance means something like "more than a few minutes", that being several thermal time constants for the voice coil assembly.

Brand-name guitar speakers are rated on their long-term power handling ability (note the "brand-name" caveat), and they generally will survive a steady diet of their max power.

It was mentioned above, but keep it in mind. In combination with hifi speakers usually having traded efficiency (i.e. sound output per watt) for smoother frequency response, the tendency when using them for guitar is to turn the volume up to get equal loudnesses with guitar speakers. This puts even MORE electrical power into the speaker and gets it hot faster.

[Hemmel]

I think they will work great in a open cab (57l) powered by some small amp (up to 20W). They will not last "forever" Can you find the specs (T/S parameters)?

I have no idea, can't find any info on this particular model except for what's written on the back.

It was mentioned above, but keep it in mind. In combination with hifi speakers usually having traded efficiency (i.e. sound output per watt) for smoother frequency response, the tendency when using them for guitar is to turn the volume up to get equal loudnesses with guitar speakers. This puts even MORE electrical power into the speaker and gets it hot faster.

So.... should I abandon this project with my InterTan speakers ?

[seadi123]

Thanks everyone for the help . Since guitar speaker work at a different frequency then hi-fi speakers , i thought maybe some simple High/Low pass Filters would do the job ?

[Nasse]

http://www3.telus.net/bc_triumph_registry/smoke.htm hope the link works. Found it today. I believe it would not fix a damaged voice coil, even if Duke of Darkness himself has invented it. Anybody tried those new eminence speakers, i think the ad says they are designer för practice amps? (Some New 8 and 6,5 inch GTR speakers?) i hate auto correct funktion, sorry

[bool]

Thanks everyone for the help . Since guitar speaker work at a different frequency then hi-fi speakers , i thought maybe some simple High/Low pass Filters would do the job ?

In essence, yes. Look, basically, you need to control the top end, which isn't so trivial if you plan to use a solidstate amp or a chipamp. Smaller hi-fi or portable driver units are too broadband to naturally "lowpass" the signal to conform to what your ears are accustomed to hear as "proper". There will be too much buzz. Experimenting with some series inductance (if there was a crossower from where you want to pull the driver that's easier) could be benefitial as well.

Of course, if you don't plan to turn the ss amp to 11, you can pre-condition the signal with some low pass filtering, but you will most probably have to do it against your particular loudspeaker, so no hard and fast rule here.

Controlling the "too much bass" could be as simple as reducing the output coupling cap (at the speaker end), or again - preconditioning your signal with some low cut or similar.

Or simply f++k it up like the Kinks did..

[tca]

So.... should I abandon this project with my InterTan speakers ?

... we can still do a lot with regular "hi-fi" speakers. Go for it!

Question: what amp are you planning to use?

P.S.
Before building a complete cab try a open baffle (see pic above). You can reuse the wood if your mind changes.