[sebrof]

Hey!
OK, first off. Single driver speaker are not for everyone. Depending on you taste of musics, room size and how loud you like to listen.

Right here is the problem (EDIT: I agree that FRs are not for everyone, but some people love them for good reason).
I own 1 pair of Full Rangers but they are not my main speakers. But I do run a SET amp, and whenever the subject of SET comes up many of the responses are the same as for FRs.

The OP said, "I listen to vocal ,violin and string instruments more than anything. I am trying to see if a fullrange speaker can accurately reproduce human voice ( so far no luck with 2/3 ways)." and yet several members will tell him he won't like FRs because they don't play the rock they like to listen to.

Listen to the OP, he knows what he wants and he has articulated very well. FRs do what he is looking for exceptionally well, and that's why people like them. And those people believe the trade offs are worth it.
And little girl with guitar my ass, they also can play fairly loud and fairly complex music. Not as good as multi-ways usually, but again that's not why people who have them have them.

Cons: Usually don't rock the house
Pros: Usually small, inexpensive, efficient, and play vocal ,violin and string instruments very well.

[SET Man]

Hey!

  Im not saying it will not work for him. That is why I encouraged him to see if he can audition them before commit to it, but of course he can't.

  So, what's the problem with my statement? It is true... If you have a giant size room with a 4" drive with 4 watts itis likely that is not going work.

   Or I'm just misinterpret your post.

Take care,
Buddy 
   

 

[sebrof]

Hey!

  Im not saying it will not work for him. That is why I encouraged him to see if he can audition them before commit to it, but of course he can't.

  So, what's the problem with my statement? It is true... If you have a giant size room with a 4" drive with 4 watts itis likely that is not going work.

   Or I'm just misinterpret your post.

Take care,
Buddy 

Sorry for being confusing. I was agreeing with you and pointing out that people act as if FRs are for nobody because it's not for them.
I edited my 1st post to make it even more confusing 

[SET Man]

Sorry for being confusing. I was agreeing with you and pointing out that people act as if FRs are for nobody because it's not for them.
I edited my 1st post to make it even more confusing 

Hey!

     No problem... hard to get mad at a fellow SET and Single driver speaker user.

    One thing I don't like personally is, full range driver in bass reflex box.... I just don't believe in that. For me if you want full range driver especially hi-efficiency one you have to go big...  a good size back horn loaded for the driver, or even transmission line would do for me.

     And yes, driving them with good SET power is cool with me. 

Take care,
Buddy

[kinku]

after reading little bit about Full range and speakers me too think bass refex is not the best idea for FR speaker. But what about a closed enclosure with sub?

[Quiet Earth]

Why can the bass reflex technique work so very well in a two way speaker but not in a single driver speaker?

[kinku]

In my understanding the bass reflex work by bringing down the speaker cone's ineherent resonant frequency(Fs) down  to make a lower bass response. Say if Fs 70Hz, using a bass reflex it can brought down to 60. But needless to say that will increase intermodulation distortion in Full range which is not designed to handle that low of response well. Martin please correct me if wrong. This is the knowledge from 2 days reading.

[rjbond3rd]

Bass reflex is perfectly fine for single driver, as long as that driver is suitable for BR to begin with.

Here is my newie understanding.  There are drivers which don't work in BR so well, and those are the overdamped (low Qts) drivers which need more help in the bass from the cabinet than a BR can manage (in order to overcome the massive magnet relative to the light cone).  So those particular drivers are traditionally put into horns, but any driver can perform on OB with supporting woofers.

Sealed works fine as long as you're okay with the tradeoffs.  In general, the sealed box will give you "less bass" because it starts rolling off very high (as measured by the driver/box combo's F3, point where the falling response has dipped 3dB), but with a slower rolloff (6dB/octave) and superior transient response.  The bass reflex will have a much lower F3 (deeper bass!) with a steeper rolloff (24dB), and potentially issues with transient response (but in practice, if this is audible, you keep tuning or redesign -- it's not such a problem with a well-designed cab used within its sane limits).

So for example (for a given suitable driver), a sealed sub gives a nice tight response, with low notes that are clean (but softer in amplitude).  A bass reflex sub will be more efficient, but the bass can sometimes be "boomy" or " bloated, interacting with the room in bad ways because there's "too much bass", causing people to say it sounds "thick" or "slow".

Some people feel that the best combination is sealed wideband, sealed sub.  Then you mount the sealed widebander on top of the sub, offset to account for phase, and you can use a first-order series crossover (a cap and a coil, that's it).  I've heard this and it's very good, but there are excellent examples of -every- configuration: sealed, BR, TL, MLTL, BLH, front-loaded horns, etc.

EDITED: Oops, I had put the BR rolloff as 18dB/octave, but as Martin notes below, it's 24dB.

[MJK]

In my understanding the bass reflex work by bringing down the speaker cone's ineherent resonant frequency(Fs) down  to make a lower bass response. Say if Fs 70Hz, using a bass reflex it can brought down to 60. But needless to say that will increase intermodulation distortion in Full range which is not designed to handle that low of response well. Martin please correct me if wrong. This is the knowledge from 2 days reading.

An interesting phenominon occurs when you combine two resonant systems, the driver and the enclosure, having approximately equal fundamental frequencies fs ~ fb. It does not matter if it is a ported box (bass reflex) or some form of quarter wave enclosure (TL, MLTL, or BLH), the behavior of the resulting resonances is the same. When two systems, with approximately equal fundamental resonances are combined, the resulting system will have two new resonances that bracket the original resonances as shown below.

f_low < fs~fb < f_high
 
The new resonances at f_low and f_high are the two electrical impedance peaks you see for a bass reflex enclosure and an unstuffed quarter wave enclosures.

The lower resonance, f_low, is the driver moving into the enclosure pushing air out of the open end or port and this produces the 24 dB/octave roll-off of a bass reflex or TL design. The mode shape (vibration theory term - the motion of vibrating systems can be completely described by their natural frequencies and mode shapes) has the driver mass moving into the enclosure and the open end or port air mass moving out of the enclosure.

The higher resonance, f_high, is the driver and the air at the enclosure opening moving out of phase combining to produce SPL. The mode shape has the driver mass moving out of the enclosure and the open end or port air mass moving out of the enclosure, the two combine. As you move up in frequency above f_high the driver's output dominates and you get the SPL curve of the driver.

The common misconception is what happens at fs~fb which is the minimum between the two impedance peaks. This is not a resonance condition in the combined driver/enclosure system. This is the point between the two resonances where the mode shapes combine and result in the driver mass almost stopping (mode shapes cancelling the driver motion) while the motion of the open end air mass combines (mode shapes reinforcing the motion) to be a maximum. When the driver almost stops moving the only significant impedance is the resistance of the voice coil which is the minimum between the two resonant peaks. At this frequency almost all of the bass SPL is being produced by the air in the enclosure.

If you look at the plotted output from one of the shareware programs that shows the driver SPL, the port SPL, the combined SPL, and the driver displacement curves all plotted on a common frequency axis you can visualize what I have described above. The bass response really starts between the two impedance peaks, this is where the driver motion passes throught a minimum. So from a distortion perspective, if the music does not contain much output below 40 or 50 Hz (typical of acoustic and not electrical instrument recordings) and the system is tuned near this frequency then there is not a lot of distortion created by excessive motion of the driver. I think this is one of the advantages of the ported or quarter wave enclosures.

The other problem you touched on with full range drivers is weak bass response. This can be caused by two things. If your full range driver has a low Qts, say below 0.3, then the rising SPL response will require the enclosure to produce significant amounts of low frequency bass and even low mid range output. You will need a really good enclosure design and probably some room boundary reinforcment. It is a little easier with a full range driver that has a Qts between 0.4 and 0.5.

The next problem you run into is the baffle step issue. Depending on the width of your front baffle, the acoustic output from your speaker will gain between 3 and 6 dB of SPL output between 400 and 1000 Hz. If this is not addressed then the system will sound bass light and maybe even harsh. I use BSC filters to tame this problem, purists resist filters and suffer the consequences. In a two way system this is usually handled by the crossover from the woofer to the tweeter and carefully matching the SPL/W/m values for each. You cannot ignore baffle step resposne, it will bite you in the end.

In some ways full range driver speaker systems are fairly easy to design if you recognize the issues up front. You can design a simple bass reflex box and then include a BSC filter to adjust the balance between low frequency and high frequency SPL output. A small two way system with a crossover can be difficult to get right, designing crossovers is an art, and for somebody starting out the full range option will be challenging enough but managable. You cannot expect thundering room shaking bass from a 3 or 4 inch driver for HT or heavy metal, you cannot expect the silky smooth crystal clear highs from an 8 inch driver. But for acoustic music like small jazz groups of chamber orchestras where the midrange is critical, full range driver systems can sound really good.

[MJK]

duplicate post

[kinku]

Martin , great explanation. Really appreciate the time you spend to educate new full rangers.
Unfortunately your explanations lead to more questions.
What would be  the ideal size of a cone that would reproduce human voices more accurately, in your opinion?
I went with 5-6 inch cone from a common sense guided assumption ,from discussions and reading. Larger cones for low frequencies and smaller cones for higher frequencies.
My next question is from your last post, a bass reflex enclosure with a full range speaker with Qts between .4- 0.5 ,can still be better than a two way system  with poorly designed cross over  ,provided it uses a baffle step correction.but do not expect rocking bass and high end treble,is that close to what you are trying to convey?
If so what is the benefit of a TL or BLH over BR enclosure?

[MJK]

What would be  the ideal size of a cone that would reproduce human voices more accurately, in your opinion?

I don't know if there is an ideal size, I would think that any decent full range driver should be able to do voices. It is the very bottom and the very top that is being traded off versus size in most cases. I say in most cases because there are exceptions to every blanket statement. A few of the good 8" full range drivers do a very good job with the highs also and a few of the smaller full range drivers will do lows, but you will probably pay more for them then the inexpensive Fostex drivers. Some of the exceptions might be the Fostex F200A and the Tangband W8-1772 or 1808 for 8 inch drivers and the Jordan JX92 or JX92S for smaller drivers.

My next question is from your last post, a bass reflex enclosure with a full range speaker with Qts between .4- 0.5 ,can still be better than a two way system  with poorly designed cross over  ,provided it uses a baffle step correction.but do not expect rocking bass and high end treble,is that close to what you are trying to convey?

Yes, that is generally what I am trying to say. I think this is really true for the Fostex FF series I believe you were considering in another thread.  There are trade-offs and exceptions to every rule.

If so what is the benefit of a TL or BLH over BR enclosure?

In most cases a TL and a BLH are the same thing in reasonably sized enclosures.

http://www.quarter-wave.com/Horns/TL_and_BLH_Physics.pdf

A rear vented TL/BLH that is corner loaded can produce enough bass to eliminate the need for a BSC filter. Having the large open end or mouth means that a lot of bass can be achieved without dealing with port noise problems that sometimes occur in a bass reflex design. My latest thinking on BLH design is found in this document on my site.

http://www.quarter-wave.com/Horns/BLH_Design_Article.pdf

[frank111]

 You have to listen to Omega/ HoytBedord lines. As a frugal audiophile the HoytBedford 1's have impressed me & visitors in my home for 2 1/2 yrs now. I operate them thru a 50 watt McIntosh amp which is more than enough. One watt 96 decibels @ 1 meter, & I have run them in excess of over 105 decibels with Sinatra and Sabbath.(huh? speak up I cant hear ya). Based on the math, theoretically I could have peaks of over 112 or so but my galpal & cat probably would give me the boot.(suprised that hasnt happened yet, but then again I bought the house). The HoytBedford 1's reproduce music effortlessly, have a pleasant frequency response, and the furniture type quality is why they are in my living room. For bass in normal or low levels I just press in the loudness button on the preamp and all is fine.

[MJK]

Whats the difference between the Hoyt Bedford and the Omega line? They look like very similar designs.

It would be interesting to see some independent measurements of impedance and SPL/W/m of each speaker.

[kinku]

I recently read,  any speaker that reproduce more than 3 octaves from audio spectrum is destined to have distortions in sound. I am wondering how the Full range speakers are able to do that magic?

[cujobob]

  Well first off single driver speakers use no crossover. Advantage. FR speakers cover more of the frequency range. Single drivers are truer to the source. They have a linear reproduction. FR speakers when done right meaning crossover can come close but no cigar.
   Image size though IMO is where the SDS fails in direct comparison. Scale is important in recreating the live event.


charles

Single drivers aren't necessarily truer to the source. Many struggle with highs or lows or have dips/peaks in their response. If they were truer to the source and better than typical multi-ways, they'd be more popular. There are a lot of limitations with single driver speakers, however, if you can live within those limitations...you can get great sound for not a lot of money.

I have a few small rooms and am looking at single driver speakers a bit..for my purposes, they should do quite well. I would cut any single driver speaker off fairly high to at least one sub as to not restrain dynamics. I think a small single driver speaker that can do well to maybe 80-100 hz with good mids/highs, then handed over to multiple subwoofers would be the best way to get good sound out of one.

Distortion in audio is a subject of much ignorance. Distortions the ear can't pick up don't mean much, do they? It also depends on frequency, of course.