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  #1  
Old 06-02-2003, 06:47 PM
barbara barbara is offline
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no-crossover for better sound?

i have been reading about some audiophile types building systems that don't use crossovers because crossovers distort the signal.

what is the verdict on this approach with regards to (analog) club system design as well as just in general? would there not be tradeoffs to going with no crossover that would sort of negate the benefits? i found it very confusing and i was sure some of the people who frequent this forum would have some opinions on this. i'd love to hear what you think.
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  #2  
Old 06-02-2003, 07:14 PM
clubman5 clubman5 is offline
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no-crossovers

There are speakers that use a single driver to reproduce full range! The Lowther is most common! However, you would have to hear them and decide for yourself if you like it. Yes, anything in the signal path causes some sort of distortion or anomaly! But, usually a single driver cannot effectively reproduce to entire frequency spectrum faithfully. Generally speaking a woofer cannot reproduce the extreme high frequencys. and a small woofer ( 5in, 6.5in, etc ) cannot get down low!

Years ago Lowther single point source speakers may have been ok! But in 1958 many consumer speakers did not have response above 10K and much music from then ( the recordings ) didnt either!

The best example today of no crossover would be Biamping or tri-amping! This way you divide your frequencys BEFORE your amps and connect amps directly to their related drivers. This yields substantial improvements, especially in the bass.

For truly great reproduction of music you need ( IMO ) a three way speaker system. Woofer, midrange, and tweeter!

Hope this helps.
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  #3  
Old 06-02-2003, 08:00 PM
barbara barbara is offline
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hmmmm

Ok, maybe I am misunderstanding what these guys are claiming. When they said no crossover I was assuming they meant there was no crossover in the system anywhere (not just within the speakers). Needless to say this confuses me to no end!

I managed to find the site again that I was reading this on if you would like to check it out. I still can't find any mention of crossover points prior to the amps (or maybe that's built into the amps themselves?).

http://www.royaldevice.com/custom2.htm

Sorry if I'm missing something obvious here I'm just trying to get a better understanding of these issues. Thanks for any responses!
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  #4  
Old 06-02-2003, 08:56 PM
clubman5 clubman5 is offline
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The Royal Subwoofer

This sub is basically a GIANT bertha built into your foundation. Anyway, the reason they use NO xover on this sub is because folded horns act as an acoustic filter. So, the response is acoustically attenuated above a certain frequency at a specific amount of decibels per octave! The enclosure acts as an acoustic xover. So, they prefer to use no electronics. It works but is debateable as to how right this practice actually is! Yes, you dont alter the phase response of complex music signals, and less electronics means less distortion. But the amplifier is also amplifying signal that the sub WILL NOT reproduce! This means amp power is being wasted on music signal that you wont hear from the speaker. I have seen this site before and marveled at the built under your floor subwoofer, but you gotta have some house to have this. Not to mention a bank acount to go with it!

technically, Less is more. So, Im sure it works! What Im not sure of is how it sounds!

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  #5  
Old 06-02-2003, 09:12 PM
clubman5 clubman5 is offline
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BTW

A " Lowther " speaker is only ONE driver to play everything from the bass all the way up to as high as it can go. A lowther uses NO crossover either.

Its a full range speaker. you already have something similar! Your TV set has a little speaker with NO crossover and plays the entire frequency range. Not as well as any of the speakers were talkin about, but it is a speaker with no crossover.
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  #6  
Old 06-02-2003, 09:12 PM
soundmanshorty soundmanshorty is offline
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this is diff

than a bertha, this is a 5th order bandpass enclosure the bertha works on completly diff principles.
if the rear chamber was tuned it would be a 6th order enclosure and if it had a x-over it would be a 7th order enclosures. these were popular in car audio if you knew how to build these properly for single 10s or 12s.
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  #7  
Old 06-02-2003, 09:48 PM
barbara barbara is offline
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yes

Yes I'm familiar with full range drivers. I remember pulling some crappy paper ones out of the dash of my car once. Yuck!

Thanks for the info regarding the lack of crossover for the sub. I was gathering from some of the comments on that site that the enclosure was built to filter out frequencies itself to remove the need for a crossover, but I had to wonder if this enclosure design does not impart some innaccuracies/character/distortion of its own, thus sort of defeating the purpose of not using a crossover. If so I suppose it's a matter of preference as to which approach sounds better (either that or I'm just wrong ).

So is it safe to assume that there MUST be crossovers used somewhere within the audio room (pre or post amp) to separate frequencies between the mid and high freq drivers? Or, are those drivers' enclosures also designed in such a way so as to rolloff the frequencies themselves, thus eliminating the need for any crossover? After all it does say across the top of their page "the highest efficiency ever obtained with NO distortion using NO feedback tube low power amplifiers and NO crossover on the speakers."

Thanks for the insights.
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  #8  
Old 06-02-2003, 09:55 PM
clubman5 clubman5 is offline
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Your welcome!

and just to add my personal opinion, ALL enclosures manipulate and distort the signal to some degree. How much is the question. And whats acceptable is usually the designers choice. However, I use a crossover on ALL my speakers. Even though I have folded horns that attenuate the signal I still use a crossover to keep unwanted frequencys out of the amps inputs!

Gotta love their amp though, a WHOPPING 1.7 watts of tube power. Itll work in a home enviroment, but never in pro or studio use!
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  #9  
Old 06-03-2003, 04:35 PM
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daveg daveg is offline
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Crossover simplicity

Some Home Hi fi builders are using just a single oil capacitor in series with JBL or EV slots to extend HF on their old horn hi fi designs.

A first order high pass crossover, as Scott says these are of no use for high level sound!

It is posible to do things very simply if building a home system for fun.
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  #10  
Old 06-03-2003, 06:03 PM
bull19 bull19 is offline
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You can make a 2 way speaker without any crossover.

15 inch or 12 inch bass driver and large piezo tweeter horn or a few square piezo tweeters.

A piezo also is a very high impedance,so you can wire many in series without overloading the amp.
And piezo's can take more abuse than normal tweeters with crossover,since the most a piezo might need is a resistor in series when using amps which go beyond 20khz in frequency range.
The only downside with piezos is effientcy,but that can be solved by using a few more,until the desired match in sensitivity is met with the bass driver's sensitivity.
Last but not least,the no.1 complaint about piezos,is they mostly sound harsh,brittle or thin sound,thats why most people prefer using compression drivers and a crossover.

Also it's better not to use a low pass filter with a bass driver in a 2 way cabinet,otherwise you lose the midrange frequencies from the bass driver and then it sounds muffled.
Only in bass bins you want the bass driver only producing bass,so then you use a low pass filter.
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  #11  
Old 06-03-2003, 06:33 PM
massappeal129 massappeal129 is offline
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full range drivers

I'm gonna try and build a smallish near-field monitor out of a fostex FE167E full range driver, for a first time speaker project that wouldn't require me to design a crossover. The single point source will probably be better for the nearfield (though a coaxial driver would probably make a better speaker).

The only time I could see myself using a fullrange driver in a club enviroment is for a cheap and easy stage monitor (the ones that sorta lay on the ground).
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  #12  
Old 06-03-2003, 06:53 PM
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Full range drivers

If you try and get high levels out of single driver you will tend to get a nasty shouty sound. Most single driver systems are Hi Fi from the very early days or guitar cabs.

I am not aware of the fostex driver you mention, the only fostex I know are the powererd baby monitors loved by broadcast engineers etc. These are very expensive.
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  #13  
Old 06-03-2003, 09:38 PM
jaybike jaybike is offline
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crossover for two way

Tom you have to use a crossover on a two way loudspeaker when using piezo tweeters such as installing a resistor on the crossover board for the tweeters just to be on the safe side because sending hi frequency info to a woofer can cause serious damage to the woofer and plus you don`t want to send hi frequency info to the woofer as you will not get full good signal response from the loudspeaker. So it is best to put a crossover in a two way loudspeaker and send the frequencies to their proper drivers. This is for full range loudspeaker systems that have crossovers. Also Tom for a club sound system you will want to have an external three way crossover unit installed and have three amps driving the appropritate drivers for the loudspeaker setup such as HI, MID, LOW Drivers being driven by their appropritate amplifiers. The whole issue is you will always need a crossover to filter the frequencies to their appropritate drivers.
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  #14  
Old 06-04-2003, 02:01 AM
clubman5 clubman5 is offline
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jason

you HAVE to have a xover on high frequency drivers as excessive low frequency will burn a diaphragm quite easily! However, NO woofer will be damaged by excessive high frequency! A woofer operating at and above its rated frequency limits will do ONLY 2 things. 1. A woofer being operated to its frequency limits will tend to beam in the higher frequencys. 2. A woofer recieving input above what it can reproduce simply will not put out much, if any sound above its limits. But high frequencys WILL NOT blow a woofer. Standard practice in selecting drivers for a speaker system is to choose drivers with response of at least an octave above or below where you will be crossing over!
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  #15  
Old 06-06-2003, 01:13 PM
bull19 bull19 is offline
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The Eminence Beta 12LT speaker a 12 inch fullrange with dual cone,45hz-10khz [a very good frequency range for a single driver fullrange],225w rms,2 inch voice coil,kapton former,38 0z magnet.

Piezos tweeters DO NOT need a crossover, [because they are only bi-morph crystals and a small paper cone],but they can't handle more than 75w rms each.Use several in series for the power required,or use a Powerline CTS/Motorola tweeter protected to 400w prog[includes a built in PTC resistor and Tungsten bulb].

So you can build a 2 way speaker system without using a crossover.
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  #16  
Old 06-07-2003, 07:06 PM
clubman5 clubman5 is offline
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Eminence

Yes Tom your right about the eminence. But what about frequencys above 10k? So, You still need a tweeter of some sort. Listening to music reproduction with a response to ONLY 10k will not be very satisfying. Kind of rolled off, dull sounding.
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  #17  
Old 06-08-2003, 11:18 AM
bull19 bull19 is offline
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The Eminence Beta 12 LT [45hz-10khz] with a piezo tweeter,either a piezo which is 1.8khz - 20khz,or piezo which is 3.5khz-30khz.
This makes a simple,low cost 2 way speaker ideal for foldback wedge monitors[without the need for any crossover].
Also Volt sell some very good fullrange dual cone drivers which have a frequency range of 50hz-15khz,but they are quite expensive.
A piezo tweeter can handle much more abuse than a normal voice coil tweeter,since a piezo is made of a ceramic bi-morph,brass metal plates,and silver electrode.Attached to a small paper cone and coupled to the air via a horn.
As the piezo tweeter is capacitive in nature,therefore in rejects low frequencies,and also it's rated about 1000 ohm at 1khz,so that it presents very very little load to the amplifier.But they can't handle more than 75w rms each,so you wire them in series,until the power handling is achieved,or you buy [Motorola/CTS] Powerline series,a piezo tweeter with a bulit in protection circuit which makes the piezo handle 400w prog/200w rms [PTC Resistor in series,Tungsten bulb in parallel];this is good because as the input woltage increases,the PTC draws the extra current,and lowers it to a safe level for the piezo,and the tungsten bulb lights up to prevent a drop in sound pressure,this is simular to a level compressor.
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  #18  
Old 06-08-2003, 12:00 PM
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1000 ohm

I could see some amps not liking that.
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  #19  
Old 06-08-2003, 09:58 PM
kingk kingk is offline
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no crossover

>>>"Anyway, the reason they use NO xover on this sub is because folded horns act as an acoustic filter."

It's true that a horn acts as an acoustic filter, but this is rather a disadvantage than a reason to use horns in most cases and has not much to do with using a crossover filter or not! A horn can be compared to a high pass filter. The lowest frequency that can pass through the horn is dictated by the circumference of the mouth (where the sound leaves the horn). The bigger the area/circumference of the mouth the lower the frequency that can pass (cut-off frequency of the horn). Reproducing low freqencies takes a very big and long horn ! So the fact that a horn acts as an acoustic filter is not really an advantage .
The benefits of using horns are efficiency and directing sound. A horn is in fact an acoustic transformer that couples the drivers cone's movement to the air in a more efficient way than free radiating drivers.

The reason to avoid crossovers has nothing to do with using horns or not. To adequately cover the audio band with "normal" drivers, three or more drivers are needed (in theory 4 are needed, since the frequencies a driver can reproduce are dictated by its dimensions - a driver can only cover adequately 3 octaves of the audio spectrum). Active or passive crossovers cut the audiosignal in pieces and send the right frequencies to the dedicated drivers or amplifiers+drivers. This creates a lot of possibilities for screwing things up such as phase shifts, time delay errors, distortion, ...
This is one of the reasons why some audiophiles prefer full range drivers. These drivers (most of the time a small whizzer cone inside a larger cone, coupled to the same voicecoil) can produce a broad range of frequencies so no crossover filter is needed. (for hifi reproduction any crossover is especially to be avoided in the critical listening band of 300 to 3Khz where most of the musical information is and where our ears are most sensitive !). Since most full range drivers produce lower SPL's at medium to low bass, they are usually mounted in a rear loaded horn, calculated to amplify the lower frequencies. Another reason to use full range drivers is the fact that these drivers radiate sound from one single point (not 3 or 4) wich results in better stereo imaging.
Of course most of these benefits are only usefull for hifi reproduction, where people want the reproduced sound to be as close as possible to the original recorded music. Avoiding any unneeded component in the signal path is one technique for getting better sound.
All this has not much meaning in a club where, apart from the fact that these full range drivers could never cover a large area - not just one "sweet spot" - with the right amount of SPL's, most of the music being played was never performed live, so there is no reference to the original sound at all. Coloration of sound in clubs is just a matter of taste !
So I don't think Scott and Shorty will be bypassing their RLA X-overs soon in their search for better sound !

PS : papercones aren't crappy. The best audiophile cones are still made out of paper !
PS : for better sound, leave out the mixer ! (no matter how good that bozak sounds, it is probably the biggest source of distortion in the system), just multiply the soundsystem and give each source its own preamplifier, amplifier and speakers (I'm not really into economics )

http://www.aer-loudspeakers.com
http://www.fostex.co.jp/int/pages/sets/prodset.htm
http://www.lowther-america.com
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  #20  
Old 06-08-2003, 11:10 PM
clubman5 clubman5 is offline
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you are right

but the Horns folds act as a filter for the higher frequencys to! Its always been known that folded horns are only useful to about 400hz. And even that high is questionable, and there are also phase problems with horns too. However, large folded horns have a unique sound for sub bass!

I have NO intention of giving up xovers! I cant. And the RLA, well, it just has a sound I like! bear in mind, the RLA does introduce coloration, but a coloration I like!

and yes, in a club or any high level enviroment you MUST use xovers!

But, you did explain it very well.
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  #21  
Old 06-09-2003, 09:16 AM
kingk kingk is offline
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folded horns

I don't think (folded) horns really filter out high frequencies unless a front chamber is used. It is certainly true that high frequencies would be colored very badly by a folded horn (especially 180 degree bends are to be avoided).
If a front chamber is used in a horn (this is a space with a certain volume between the driver and the horn mouth/actual horn) this front chamber acts as an acoustic filter, keeping frequencies above a certain point out of the horn. A front chamber is often used in back loaded horns to keep high frequencies out of the horn to avoid interference with the sound that is radiated from the front of the driver. This way only the lower frequencies that can't be produced very well by the driver are amplified by the horn.
A folded horn is always a compromise to fit a very large horn into a small cabinet. The folds will generate phase shifts, distortion,... and this will color the sound (which is no problem if this is just the sound that you like - just like any $10000+ tube amplifier will color sound and still be loved by a lot of audiophiles). High frequencies are much more directional than low frequencies and the coloration of a folded horn design would be especially audible in the higher audio band (the higher frequencies can't by guided very well by a folded horn but are rather reflected by the folds which causes them to start bouncing around in uncontrolled directions).
The most important reason why folded horns are only used for bass reproduction is the size factor.
A horn for frequencies above 400 Hz takes about 6" of lenght and a mouth of about 10" x 10" (for a round or square horn radiating into free space). So it would be crazy to start folding such a "small" horn to fit into a smaller cabinet but at the same time compromising the sound. A non folded horn that goes down to about 20 Hz would take a lenght of about 15 feet (when placed against a wall), so even for a club this would be rather big and folding the horn starts to pay off (even if this introduces some coloration).
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  #22  
Old 06-14-2003, 02:18 PM
kingk kingk is offline
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high frequencies and horns

Hey Scott, I just read an article about front horns and it seems that some horns DO filter out high frequencies, just as you mentioned. I thought this was only the case when a front chamber was used, but very long horns also act as a filter for high frequencies. Guess you were right after all. I should have known better !
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  #23  
Old 06-15-2003, 12:50 AM
clubman5 clubman5 is offline
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simple rule of thumb

With bass, folded horns were you CANT see the woofer are OK for sub bass. But, everything above the sub bass, i.e., woofer, low mids, etc, you must be able to see the cone!

Any cabinet, except for subwoofers, you use that you can SEE the cone will play satisfactory up into the low mids!
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