Mysterious crossover worth replacing?

[greatsushi]

It’s inside a 3 way speaker by audio intimidation. Rated 40hz-20k 4ohms 90dB 120w

I got these cheap and thought at least use the cabinets. But anyway to me the cross over is doing something. But it doesn’t sound like a great split to me between the speakers

Any advice?

 

[eriksquires]

Hi Sushi,

Looks like a classic 2nd order, 2-way (not 3) crossover with a nice film cap in the tweeter. Before you start playing, have you ever analyzed a speaker before? Do you have the proper tools or willingness to acquire them?

If you just want to play a little, and get on with your life, I suggest changing out the yellow film cap for an inexpensive Mundorf MKP.

Otherwise, I'd step back from what you bought and learn about speaker design, maybe check out publicly available DIY designs. Honestly one of the worst ways to start is from a cabinet. Best to start from drivers, and work your way towards the right cabinet after.

Best,

E

 

[greatsushi]

Thanks for your reply

That’s crap, shows what kind of effort some companies put into their speakers. I was just thinking about buying this? 2 skytronic 3-Way 400w Crossover (passive) for speakers dj disco home audio  | eBay

But I am planning to build some speakers. I used to be a cabinet maker so the enclosures should be straight forward. And I did physics at uni so hopefully I’ll understand the acoustics stuff. But never did much electronics. I have built an effect pedal modelled on the mutron but that was just following a pcb and adding a few extras. Nothing like designing my own stuff or knowing exactly what’s going on in the thick of it.

I’m a bassist and would love a speaker to accurately get down to low frequencies. Low E is 41Hz so it would be nice to have a bit of headroom. Have you got any wisdom on getting down to low frequencies? It’ll be in a studio setting so I can’t have them huge is the thing.

I’ve been looking into different enclosures and there was one that looked particularly interesting. the volume was like a U bend with the port near the top again. I can’t remember what it was called but that had good low frequency response I think

 

[greatsushi]

Also if I do some sound frequency tests. Just simply ranging the frequency and plotting the spl how do I know it’s not the amplifier that’s adding extra ‘stuff’?

Also basic testing I can do with my laptop and a mic right?

I’ve got lots of electronic components left over from the pedal. No inductors though. But I’ve got blank pcb’s as well.. is there a way to add on a bit to the crap crossover to make it a 3 way?

 

[greatsushi]

Yeah it’s 3 way. The bass and mid look like the same driver. It’s a massive enclosure so I thought the bass would be alright. 8” drivers as well.

 

[system7]

greatsushi, do me a favour and publish a picture of this mysterious Audio Intimidation speaker of yours.

Is it the S800B model?

I really can't waste time on mysteries. If you ask a question, it is merely polite to supply sufficient information for a thoughtful reply. Otherwise you are wasting everybody's time. Certainly looks like a MMT two-way to me.

 

[greatsushi]

Sorry Steve I didn’t think anyone would know about it. It is audio intimidation s800 doesn’t say B anywhere. But might be.
I can’t find anything about them online.

They’ve got wood vaneer on thr side of these speakers

 

[eriksquires]

It's still a two way if the two woofers are doing the same work. No, don't just buy an off the shelf crossover and stick it in a cabinet.

If I were you, I'd leave these alone or MAYBE upgrade the tweeter cap. $7 each

Otherwise, I'd suggest learning a lot more before attempting a redesign.

Best,

E

 

[system7]

Well, what are we looking at here? A TMM for sure.

And a mysterious crossover:

I think I have seen this sort of thing before.

It's not hard to wire two 8 ohm woofers in parallel to make a 4 ohm TMM unit, in effect. It ends up looking like a Visaton Alto circuit. Not rubbish, by any means.

 

[greatsushi]

Why would the middle woofer be getting more frequencies to it?

The bottom one is mostly bass but some mids. And the middle woofer is getting almost everything it seems. Apart from the really high frequencies

 

[Fast Eddie D]

It's a "two and a half" way. Lower woofer is crossed over at the baffle step, upper woofer is crossed over to the tweeter.

 

[eriksquires]

Hey Eddie,

For that to be true, you need 2 low pass filter sections. I only see 1, unless everything is 1st order, which is even worse.

Best,

E

 

[Gnobuddy]

Well, what are we looking at here?

Bizarre brand name, check. Reasonably attractive appearance, check. Almost useless crossover network, check.

Here's what we're looking at: White van speaker scam - Wikipedia

(These speakers may not actually have come from a white van, but they are the type of speakers that created and sustained the white van scam for a good two decades.)

I myself have a fondness for these sorts of good-looking but poorly designed "white van" speakers. If you get them cheaply enough to be worth it, and pair them with an equally cheap class-D audio power amplifier board from Ebay or Amazon, they can do many non-critical audio jobs around the house: computer speakers, music for the patio or kitchen or bedroom, et cetera.

I recently bought a small D'Appolito (aka MTM) "Digital Research" speaker for $5 from a local thrift store. Like all white van speakers, the appearance is decent - looking good is the primary selling point, after all.

Also like all white van speakers, the audio quality varies from dubious to awful: in this case, the tweeter appears not to be connected at all, by the sound of it. (It's also possible that the tweeter did function at one time, and the previous owner burned it out.)

But the lack of a functioning tweeter makes this $5 White Van Special, paired with a $15 class-D audio power amp board and a guitar effects pedal acting as preamp, a quite decent little late-night electric guitar amp. Extended treble response doesn't sound good with electric guitar amps anyway - they never have tweeters!

Personally, I wouldn't spend money on trying to upgrade these types of speakers. They usually use the cheapest drivers that can manufactured, so they are unlikely to perform well no matter what you do to the enclosure or crossover.

IMO these types of speakers are best enjoyed for what they are - cheap enough, and good enough, for non-critical applications. You have a nice cheap hamburger, enjoy it, but don't expect to be able to turn it into prime steak!

-Gnobuddy

 

[Fast Eddie D]

Hey Eddie,

For that to be true, you need 2 low pass filter sections. I only see 1, unless everything is 1st order, which is even worse.

Best,

E

A schematic would be helpful.

What you describe is definitely a 2 1/2 way. Maybe the "midrange" woofer has no crossover at all! It's not uncommon in cheaper speakers (a lot of them) and the engineer can match the tweeter crossover frequency to the natural rolloff of the woofer, sort of. Obviously you have to have a certain kind of woofer for this; one without big midrange resonance nasties. This is what a lot of "classic" replacement woofers are like. People buy them to replace old woofers. And they work even better in a properly designed system.

And first order isn't always bad, depending on the crossover frequency and drivers used. I've looked at a lot of speaker designs that used first order for the woofer and second order for the tweeter. Remember, woofers have a natural rolloff curve so a first order might act like a second order, depending on a lot of stuff. Tweeters not so much at the crossover frequency.

 

[Gnobuddy]

...woofers have a natural rolloff curve...

That natural rolloff curve is caused by cone break-up modes, which also create large amounts of distortion, and usually also negatively affect the sound dispersion pattern.

So using the natural rolloff of the woofer as a crossover more or less guarantees that there will be excessive harmonic distortion, erratic frequency response, and an erratic dispersion pattern from the woofer, before it hands over to the tweeter.

This is why a good speaker system rolls off the woofer at a frequency well below the woofer's own treble rolloff: to attenuate the nasties that go with cone breakup as much as possible.

Tweeters not so much at the crossover frequency.

The low-frequency rolloff of a properly designed tweeter isn't accompanied by any sonic nasties. But down at those relatively low frequencies, the tweeter is usually excursion-limited, and may also be power-limited.

So a high-pass filter is necessary to save the tweeter from damage due to too much low frequency energy.

-Gnobuddy

 

[greatsushi]

Thanks for all your responses guys.

Talking about that white van scam.. I got conned when I was young and naive at university. A few years later the same guy in the same van, different location asked us.. hey do u want some speakers?! Nah **** off haha

I’ll leave those shitty speakers then.

I basically want some nice small ish studio monitors with a sub to get to sub 41Hz frequencies (low E on the bass)

Does it definitely workout cheaper buying drivers separate, building the enclosure and designing and building the crossover?

 

[JensenHealey]

To get cheaper, buy second hand but stick to known and understood names / brands.

Building your own can be very satisfying, but best use a kit that has already been designed to work. Designing your own crossover is not for the faint of heart. It is non-trivial. Great hobby if you have the time (lots of time needed for iterations, testing, building, go around again & again) and the testing kit

 

[greatsushi]

Yeah that’s the problem. I haven’t really got time to invest in the whole design process.

If it’s a case of buying a crossover and drivers then building my own enclosure that’ll be easy enough. Providing there’s a build manual or some specs to what to build to.

But will it be worth it? They’re going in my studio. And I work full time. So it’s studio time in the evenings. Maybe it’s worth me buying some second hand nice speakers and it’s done then.I can’t invest in testing equipment along with all the equipment I need for the studio etc.

I just want some really nice crisp speakers. I want the highs to pop out and the bass to be well represented... ideally to low piano sort of frequencies.

Can anyone recommend some speaker brands or models that would do what I’m looking for? There’s just so many brands it’s hard to know what’s good and solid for the money

 

[JensenHealey]

But so many questions before anyone could advise....

Room size & shape?

Speakers to be floor or stand mounted? or Console mounted?

Amplifier already in place? or want to look at active speakers (not unusual for a studio context)

 

[greatsushi]

Room is rectangle. 4.5 x 3.5 x 3m... ish does it have to be exact?

I like floor standing speakers. But the smaller studio monitor style would probably be more practical. Though I’d take which ever I Can get most bang for my buck. But I guess most practical would be console mounted with some anti vibration pad things.

I’ve got a marantz bi wireable 80W per bi wired channel. And an old NAD system amplifier, I think that’s 40W ish per channel. But then active speakers save so much space. And are designed for that specific speaker operation. So either or really. There’s benefits to both.

Is it a usual thing to have two studio monitors and a sub to compliment them?