[BPoletti]

After much research, gnashing of teet, and expert direction (from TerryO and Dave Dlugos), I have constructed a bipole system using (4) FR125SR drivers.  Sealed box, 12" wide, 9" deep, 21" high, 3/4" baltic birch, 20 litres actual internal volume, no bracing (yet).  I needed it this high to get the drivers to ear level when placed on top of the sub cabinets.   

I completed the cabinets a couple of days ago.  Wired and mounted the speakers today, packed the enclosures with long fibre wool.  This evening, I hooked them up and fired up the system.  I was immediately disappointed.  The system was dark and heavy, lacking detail and without much treble.  I recalled a post from Danny of GR Research in a different thread.  He suggested putting a cap in parallel with the rear-firing driver.  I used 60mf. This made a world of difference.  Brought the speakers out, illuminated the stage, placed the instrument in precise locations.  The system is no longer overwhelmed by midbass bloat and boom. 

I still hear some roughness, dynamic compression, splashy treble (cymbals), some uneven octave-to-octave response, and a few other problems.  They problems are changing so they are probably related to breakin. 

What I don't hear is treble modulation during loud passages.  That was a major concern for running a full-range speaker.

At this point, the speakers are not near what I hope for, but they show promise.  The speakers will run 24 x 7 and I'll check in on their progress from time-to-time. 

It appears that, to reach the full orchestral dynamics I like, it will be necessary to restrict the lf on the FR125SRs and use a sub.  To keep the phase issues to a minimum, the crossover will probably be at around 200hz 1st order.  The subs are old Lambda SB12s so the crossover can't be much higher with 1st order.  But that should be enough to let the FRs sing.

Thanks to TerryO, Dave Dlugos and Danny for getting me this far.  There's serious promise with these drivers.  Time will tell whether they will be as good as my current (DIY) speakers which are pretty good.

[PDR]

Nice!

I also want to delve into the full rangers.......either the FH mklll or the maeshowes.

The frugals seem to be a whole lot less work if I dont get what I expect......but the maeshowes look so damn nice.

I would like to quote Dave if I may........."Pics?"

[BPoletti]

Nice!

I also want to delve into the full rangers.......either the FH mklll or the maeshowes.

The frugals seem to be a whole lot less work if I dont get what I expect......but the maeshowes look so damn nice.

I would like to quote Dave if I may........."Pics?"

Pics?  Coming soon to a web site near you.

[BPoletti]

After about a day of break-in, the driver spiders are starting to soften a little.  Soundstage and imaging are up to expectations.  Octave-to-octave smoothness is improving, high-frequency is much improved.  Still lacks details compared to the very best I've heard, but not by much.  There is bass but it rolls off pretty steeply around 80 - 100 (not measured, just an educated guess).

Dynamics have improved somewhat but limited by the low frequency.  I expect to add a subwoofer to take the lf off of the driver.  That should provide greater dynamic headroom. 

Was playing a superb CD recording of the Paganini Violin Concerto #2 with its famous theme.  I have not heard this piece sound better from a digital source in any system.  But in their current configuration, the speakers are no match for the dynamics of Pictures at an Exhibition or Scheherazade.     

[rjbond3rd]

Hi BPoletti,

In my experience, single-driver designs really shine on small acoustic ensembles, like jazz trios, string quartet, female vocals etc.

They most likely will never do dynamics or big orchestral (most likely -- there are some exceptions). But they can have great realism on the right music.

I heard Frank Sinatra on a big Altec VOTT (Voice of the Theatre) and his high notes came out the top horn, the low notes came out the bottom (woofer) horn.  But on orchestral, they were just sensational to my ears. Tympani would punch you right in the gut.

So maybe you need two systems

[BPoletti]

The VOtTs were fabulous for the application they were designed to address.  You're right, though.  The drivers were not integrated very well.  In those days (40+ years ago) I preferred Bozak for home use.  I had Bozak CGs until the mid-80s.  Much better driver integration, with a little crossover work, but not the definition in the midrange to be a satisfying long-term music experience especially when compared to the competition even back in the 80s. 

Back to the thread....

I've been listening to the FR125SR drivers change and improve over the last few days.  I'm also getting a little more brave with the gain control.  These little 5" drivers (that's being generous) will never handle a big Stravinski piece on their own.  But If I remove the bass, or play music without a much deep bass like the opening movement of the Pines of Rome, they handle the dynamics just fine and don't get congested during loud passages.  For that reason, I'm going to work on integrating a woofer / subwoofer to handle the low frequency. 

[JLM]

Z,

Allow me to quibble, with a super tweeter the Lore aren't full range designs, just extended range (ERD).  OTOH they do meet the criteria for this circle, so play on. 

This has been driving me nuts for days, but can someone name the similar design from about 10 years ago?  Kits were also available, packing peanuts were used for some of them (that the ERD would occasional blow out of the front port  ), and the product life seemed to run a bit long after the designer suddenly died with his widow carrying it on.  The sound was very hit or miss, which resulted in many modification attempts.

Sorry to steal the thread.   

[rjbond3rd]

Hi JLM,

That would be the Hammer Dynamics!

[Bemopti123]

I always wanted to hear a good pair of the Hammerdynamics.  They do seem to be a good value if the purchaser can do some rudimetaty wood work.

[JLM]

Thanks rjbond3rd.   

The only pair of Hammers I ever heard were way less than impressive.  The poor owner had tweaked them to death and beyond trying to find that reportedly good sound.

John, the main/obvious compromise using single driver designs is the limited frequency range.  Even if you can stretch say 9 octaves out of a driver you'll have limited bass output and/or beaming of higher frequencies.  Most fans of extended range drivers choose to add a helper tweeter or woofer rather than give up frequency range, but that's not staying true to the single driver mantra.  It's a useful compromise.  I prefer my 9.5 octave drivers, but my speakers in total cost over 4 times what the Lore does.

[chrisby]

Thanks rjbond3rd.   

The only pair of Hammers I ever heard were way less than impressive.  The poor owner had tweaked them to death and beyond trying to find that reportedly good sound.

with all due respect to the long departed John Wyckoff, I couldn't agree more - in fact that'd be polite

by the time Frank took them as far as they would go, he must have spent as much on upgrading the crossover as the pair of used Hornshoppe Horns ( FE108S if that gives you any idea of the vintage of the both ) which handily outperformed them in several areas - but most particularly in overall balance, midrange clarity and soundstage / imaging

John, the main/obvious compromise using single driver designs is the limited frequency range.  Even if you can stretch say 9 octaves out of a driver you'll have limited bass output and/or beaming of higher frequencies.  Most fans of extended range drivers choose to add a helper tweeter or woofer rather than give up frequency range, but that's not staying true to the single driver mantra.  It's a useful compromise.  I prefer my 9.5 octave drivers, but my speakers in total cost over 4 times what the Lore does.

zman - if you're happy with the Lores (for now  ), and can ignore the pissy debates that we sometimes fall into regarding the "purity" of "true" single driver/full range, that's all that counts

[JLM]

Sorry to come off as pissy, just trying to point out that traditionally single driver fans were more purists and would rather give up the frequency extremes than add a helper driver.  When you recall that bass and crossovers both suck lots of power and that decades ago small tube amps (like SETs)were the norm, it is obvious why high efficiency single driver solutions were popular.  And without much bass, a balanced presentation dictated that the treble be dialed down/out.

Nowadays with bigger amps we're free to add crossovers and helper drivers, while trying to retain the coherence and imaging advantages of extended range drivers.

I'm a fan of history and find this transition interesting. 

[planet10]

John, the main/obvious compromise using single driver designs is the limited frequency range.  Even if you can stretch say 9 octaves out of a driver you'll have limited bass output and/or beaming of higher frequencies. 

There are a growing number of 9 octave FRs available, you do give up either low frequency weight (but not quality), or high frequency dispersion or finese. It is really hard to match the midrange finesse of the best of the FRs.

Now if you look at most of the store bought boxes (even some costing a lot of money) many don't do even 9 octaves.

My preferred approach to extending a FRs FR is to add helper woofers. This fits in with what Toole is getting at with no need for mains to reach below 80 hz, and multiple woofers below that.

dave

[planet10]

...Danny of GR Research in a different thread.  He suggested putting a cap in parallel with the rear-firing driver.  I used 60mf.

An important note about this. The drivers need to be wired in series. If you try it with drivers wired in parallel, the impedance goes to zero at high frequencies and the smoke usually escapes from your mamplifier.

Bill, when you have finished getting the most you can out of the stock FRs there are things you can do to get more finese & downward dynamic range out of them

dave

[JLM]

My preferred approach to extending a FRs FR is to add helper woofers. This fits in with what Toole is getting at with no need for mains to reach below 80 hz, and multiple woofers below that.

dave

I'm so with you on that one Dave.     Several advantages of powered subwoofers versus super tweeters.  Room integration, placement, number of subs, cabinet design, and appropriate power (for each set of drivers) can all be optimized without losing appreciable coherency or imaging.

[chrisby]

JLM - I on the same page as well, but I guess it's just a personal quibble with the use of "sub" for (multiple) woofer(s) crossing over as high as 120 in some cases.

I may have already bored a few folks with details of a little HT system currently evolving, but with the very flexible bass management built into even the most modest of current surround receivers, it's possible to adjust XO points for at least all 3 main front row channels (plus perhaps the new front "height" channels?).  This is a case where the combination of a decent wide-bander capable of say 8-9 octaves ( Alpair7) and multiple woofers really comes into its own.  Freed from the heavy lifting, the "FRD" can work very well - the only complaint I could make is that the LFE channel is summed for mono, and if crossed over high enough, I guess you might be able to detect some localization.  Of course from my POV, since the entire "home theatre" experience buys in even more deeply than "serious" music alone to the willing suspension of disbelief that the mixed sensory assault of sights and sounds are not confined to a space much smaller than those being simulated, we can easily tune out minor artifacts.         

[BPoletti]

An important note about this. The drivers need to be wired in series. If you try it with drivers wired in parallel, the impedance goes to zero at high frequencies and the smoke usually escapes from your mamplifier.

Bill, when you have finished getting the most you can out of the stock FRs there are things you can do to get more finese & downward dynamic range out of them

dave

Yeah, the impedance would go to zero pretty fast.  But the amps I use would be OK.  (Herron amps have a short circuit safety cut-off.    )

I did some measurements using an old Technics SA-8000.  "Factoring out the room," the response was within 1.5dB of flat from 160Hz to 16KHz except for a 4dB "bubble" starting a little above 4KHz, peaking around 6Khz and back to flat at 8KHz (I guess I could put in a parallel notch filter).  So I guess that makes it around +/- 3dB from about the crossover point to the subwoofer to above where my hearing tapers off.

I guess it's time for some pictures....   

[JLM]

Yes Chris, I'm with you there (on stretching the definition of a sub).   

None of those 8 inch cube subs or 2 inch cube mains for me.  And yes, I forgot the advantage of taking the "heavy lifting" (of the deep bass) off the extended range driver.

Sorry for continuing to divert the thread.     Yes maybe pictures would help keep the discussion on track.   

[BPoletti]

As I post these pictures, please know that these are test boxes and are not what I expect as a finished product.  The width is 12" as suggested by Dave (Planet10), 21" high and around 9" or so deep built with 3/4" (18mm) Baltic Birch.

This is the "left" speaker sitting on top of a 12" Lambda SB12 subwoofer cabinet which will eventually become the left side subwoofer.  The speaker is resting on three Vibrapods (courtesy of Sam Kennard who has supplied several gazillion mixed types for testing.)  2 x Herron M-150 amps behind.




Side view.  There is a false bottom a few inches up the inside to create a 20 litre or so speaker compartment.




View of back of speaker showing speaker cable connectors and rear driver.




View of right speaker showing electronics, sources, some of my vinyl collection and my "old" speakers.  Also note the two steel cylinders on top of the speakers, about 10 pounds each.  That extra weight improved imaging and midbass definition.




Left speaker with weights on Vibrapods ready to play.





The marks on the speakers are not build errors or glue spots.  Those are from the holographic grain effects from the wood itself.  Sorta interesting and unexpected.

On using subs:

My concern about using a full range driver has been modulating the highs when the cone is flapping in the air with long excursions.  Take away the long excursions and protect the highs.  Using a sub (that heavy lifting noted in the previous post) can't possibly hurt if there is significant attention paid to the crossover.  For me that means a lot of measurement before I ever start to pick a crossover point, the patience to make the small changes needed to try to make it work, and the judgment / lack of ego to know when to throw out a design that doesn't / won't work and start again.   

[BPoletti]

Yes Chris, I'm with you there (on stretching the definition of a sub).   

None of those 8 inch cube subs or 2 inch cube mains for me.  And yes, I forgot the advantage of taking the "heavy lifting" (of the deep bass) off the extended range driver.

Sorry for continuing to divert the thread.     Yes maybe pictures would help keep the discussion on track.   

I don't feel like you're diverting the thread.  Your comments are central to the design concerns I have for this system. 

I need to add that offline information I got from Dave (planet10) and TerryO were very important to the box design.  Danny from GR gave me the idea for the cap (which made a world of difference).  They saved me weeks of tweaking.