[ajmac]

Hi All,

I'm 'new to this site and am happy to be here to see an opportunity to learn a lot, meet new people...' I posted the following before s a response to Freemand's post. I guess I should start my own.

I have been using a pair of ATC studio monitors (active) for years, and more than half of my listening is on classical/orchestral music. I found the ATCs do have a distinct presentation of classical music where it's hard to find in many other speakers. (Maybe I'm just too use to them. ) Recently I've been trying to decide whether to find a pair of subs to fill in the bass or just start with full range speakers since my pair start to roll off around 80Hz. In this searching process, I stumble on PureAudioProject and was quite intrigued. From then on I've been reading up a lot on OBs as well as DIY. I've read description of the music from OB speaker of presence, wide & deep sound stage, and the singer being on your lap. But i don't seem to come across much description regarding OB speakers playing classical music. So please let me ask:
         
             Are (well designed & implemented) OB speakers good for classical/orchestral music? Would a full symphony be too busy complex for OBs?

I also like the idea of using a wide range driver to cover the most important frequency range. Is there a particularly good/outsanding driver for classical and acoustic jazz type of music? 6.5", 8", Bi-cone, non-bi-cone, Tangband, Dayton, Alpair... I'd like to keep the budget for these wide-ranger under $250 for the pair, but the budget can be stretched if necessary. For example, I know the Tangband 1808 are over $200 each. But if they really work better for classical and jazz, I would stretch the budget.

I've read some of MJK's articles, especially on OB. I only have a limited understanding of the math, but I think I get the basic. But I'm sure I'll have further practical questions down the road. For example, would 2 Eminence Alpha15 (like that of pureaudioproject) be close to using 1 Alpha15 in H-frame in terms of bass output to match a wide/full ranger that has efficiency>95dB?

I appreciate all suggestions and the sharing of your experience.

[steve f]

I just got back from the California Audio Show. The PureAudioProject was there and was pretty good. I've also owned Linkwitz Orions (currently replaced by LX521)  Martin King is your guy for moderate open baffle designs. All you need is a saber saw, soldering iron, and a screwdriver to complete a project.

The open baffle types are very different from your ATC monitors in that they energize the room differently. They are more airy, and less precise in their imaging. If you use an existing design, you can find out if open baffle is for you. You could also build a variant of the genre like the Linkwitz mini. You could also go planar with Magnepan MMG speakers and not get your hands dirty. All of these suggestions are somewhat equivalent.

I have no idea what you mean by yout "too busy" comment.

[PMAT]

He means complex. As in needing the speaker to resolve well. Yes OB speakers can do that. The OB sound is addictive and different. They do not all sound alike though.

[flavo]

I don't have much to add except that I recently built a pair of the X-statics. I was blown away at how differently they sounded compared to the few boxed speakers I heard that were well reviewed by folks who know loads more then me. The music seemed much more around me. But they do benefit from some extra bass. Which has led me, sort of into building a whole new speaker. Or maybe just adding some H frames.
http://gr-research.com/x-statikkit.aspx
It's lead me to wonder though, what would a speaker like the Pure Audio you mentioned or Hawthorne Audio sound like? Unfortunately or fortunately I'm going to have to build a set to find out I think. The hawthorne is well regarded and you can get your feet wet pretty inexpensively.
I've been reading for a while and i'm still hesitant to jump in as I find it a bit confusing. But I think I  might just need to jump in.
Just found this link yesterday and it has a lot of nice suggestions you might find interesting.
http://www.diyaudio.com/forums/full-range/251519-best-8in-fr-eminence-alpha-15a.html

Good luck and I always look forward to seeing where these newb threads go, as they always help me.

[rabbit]

feel i have to warn against the silver iris. i owned a pair of thoes for a year and they are imo only suitable for karaoke. they have numerous complaints actually:
http://www.diyaudio.com/forums/full-range/172747-could-hawthorne-silver-iris-used-enclosure-2.html

lxmini is fair enough, not a dipole but because of the way the fullrange driver is mounted, part of the midrange will sound sort of like a dipole with good imaging.

[steve f]

Just a couple additions about the PureAudioProject drivers. Besides the basic Eminence Alpha 15, there is an updated version that uses a thicker stamped frame, and more importantly shorting rings in the voice coil motor. That should cut distortion significantly. The last, I want to call it a premium version has a cast frame (looks like from delta lite) neo magnets and shorting rings.  I haven't seen any specs on these new drivers, but they are made in cooperation with Eminence engineering.

The Neo drivers were playing at the California show. The passive crossover integration with the TB driver sounded good. Like most 8" full rangers the frequency response is tipped up on axis. Off axis, they were very nice. They also probably can take more abuse than a Lowther or Fostex unit.

I would build the system with  active DSP and crossover. The system is very modular lending itself to easy updates.

[mark@emeraldphysics]

Just a couple additions about the PureAudioProject drivers. Besides the basic Eminence Alpha 15, there is an updated version that uses a thicker stamped frame, and more importantly shorting rings in the voice coil motor. That should cut distortion significantly. The last, I want to call it a premium version has a cast frame (looks like from delta lite) neo magnets and shorting rings.  I haven't seen any specs on these new drivers, but they are made in cooperation with Eminence engineering.

The Neo drivers were playing at the California show. The passive crossover integration with the TB driver sounded good. Like most 8" full rangers the frequency response is tipped up on axis. Off axis, they were very nice. They also probably can take more abuse than a Lowther or Fostex unit.

I would build the system with  active DSP and crossover. The system is very modular lending itself to easy updates.

I would agree 100% with your comment re active dsp and crossover(s).

To really get it right in OB you need purpose designed and built drivers - and then active dsp for crossovers and eq - that would be the way to go.

There are some new ground-up designs using OB that do not utilize dsp - and these are also quite good. YMMV.

Best Wishes,

Mark

[mcgsxr]

feel i have to warn against the silver iris.

rabbit - Appreciate your sharing your own experiences.  Sorry to hear that the Silver Iris did not do it for you.  I know of several folks who love them, so as with many things it often comes down to listening preferences.

As for the OP's original series of questions - in my experience OB can be very satisfying for many musical genres including classical. 

Biamping the wide ranger and the helper woofers allows you to address any efficiency mismatch between them pretty easily.

Building OB speakers is like building any other kind of speaker - you need to determine your goals, your budget, your willingness to DIY, what concessions you are willing to put up with, your level of comfort around a kit vs going it alone etc.

The easiest way to get a feel for OB is to dive in.  Buy a set of drivers, and a sheet of mdf.  Then experiment with a sensible baffle based on the math available in various spreadsheets.

if you like it, keep refining it.  If you don't, your time and $ invested is not significant.

Or, as already suggested, get an ear on some commercial designs and see what you think.  I ran DIY OB's for 7 years.  I now have 2 sets of Maggies.

[matevana]

I have no idea what you mean by your "too busy" comment.

Since the OP mentioned reading some of Martin King's articles, he may be referring to what MLK described as speakers sounding confused with more complex (symphonic) music. I discussed this once with Martin via email.

I do think that OB is far more susceptible to this condition than boxed speakers due to motor control issues. Most drivers rely upon the air spring compliance that is created in sealed and ported boxes to help dampen movement and cause the driver to brake. Many drivers that are not purpose built for OB will simply flop around in an open baffle; this effect is compounded and more audible with more complex music forms.  Contributing to this is the often sought after high Qts TS-parameter that often correlates to smallish magnets, weak motors, and poor control.

While some drivers seem to suffer more than others, this condition can sometimes be minimized by using an amplifier with a high damping factor.

I listen to all kinds of complex music and almost never experience this effect in any of my current OB rigs.     

[Freemand]

Welcome ajmac! I am fairly new and have learned a bunch as I am also new to OB and am looking to build.

I have been pondering myself what to build and have been most curious about a Hawthorne design which is a diy called obsession http://www.hawthorneaudio.us/forums/viewtopic.php?f=2&t=5169&start=60 This may be more then you want to spend however.

I have looked into the pure audio project and am concerned the baffles are a bit wide as it sounds like the more narrower the better.

I was under the perception the Ob would create a more pin point image with voices and such. If anyone could share their thoughts on that?

[flavo]

I asked Darrel about the OBsession and he said he may at some point offer it as a DIY kit. No plans as of now from what I gather. Unless you have heard differently?

[ajmac]

I was typing on the tablet last night, but there was an error when I tried to post and lost it all. I'm going to try smaller be but a few more postings.

First, I really appreciate all your responses, explanation, recommendation, and welcome.

I meant complex instead of 'busy' for classical music. And I have this in the back of my mind, but I can't remember whether it was from MJK's articles, or the review (journey) of someone in 'enjoy the music', or in my e-mail exchange with Planet10.

My listening area is shared with my wife and children. It is a living room opened to the dinning room; therefore, the total area is like a thick 'L' shape. Space behind the speaker is fine but I can imagine myself moving the speakers out for playing music and put them back to the wall at the end of the night. But I can live with that arrangement. I only listen to moderate volume to begin with, but after 9, I'd have to lower it further down for the children to go to sleep. On the weekends, I'd listen to higher volume. I'm working on saving up to put a man-cave in the basement. I hope to get there in 15 months. If that works out, I'll have a 10 x 14 room for the hobby.

A few more questions regarding the Maggies & PureAudioProject to come...

[ajmac]

Thanks Steve for your suggestions. I pretty much have the same thought after reading Mark's (mcgsxr) post of 'Return to OB' a few days ago.

There is a local dealer for the Maggies. I should be making my way there in the following weeks. I'm not shy of trying my hands on DIY. But if they're in a reasonable price range comparing to DIY, yet I can get great music from a pair of well finished speakers, I wouldn't want to rule them out. Besides, they might be better received by my wife especially I can put them pretty much against the wall after listening sessions. And that would certainly help to better negotiate for future upgrades.

I have not heard any of the Maggies first hand, but I recall a fellow hobbyist's saying they are fairly inefficient. Would that means loosing some of the transients? What about dynamics (macro & micro)? The MMGs are posted as 86dB 4ohms, would that limit to a few high power amps to drive them well? And the 'sweet spot', is it narrow or wide as of the whole family can share?

And thanks to flavo link to diyaudio, I got some interesting reads.

I read Poultrygiest's posts on using & modifying the Eminence Beta-12lta with super tweeter & Alpha15 in H-frame. I wonder whether they work well with the more complex classical pieces? And what would be a equivalent super tweeter that I can find today?

I've also follow Matevana's original Hestia for almost all the posts. The Hestia are surely within the budget and probably be alright to be converted to active or semi-active. Would they work well with complex pieces?

I have more questions, but I'll break that into a different post. But thanks in advance for all you inputs.

[steve f]

Maggie MMGs are mail order. They were developed to introduce people to their product line. All of their speakers share a family resemblance both sound and looks wise. You are correct that they aren't very efficient. These days getting sufficient power to your speakers has gotten pretty economical. Some of our forum members are using Crown XLS series amps with their Maggies very successfully.

Here's my take on amps. Some will disagree. Unless you have speakers that are quite efficient, like 95+ DB at 1 Watt, avoid SET and most tube amps. You are better off with high powered solid state units instead. Why? Because high output amps, 250+ WPC, can drive almost every loudspeaker without clipping. This distortion, is the major reason many amps sound bad. We can't hear total harmonic distortion under about 1.0%. For most speakers, you can run a pro type Class D amp, or an audiophile one if looks matter, that will run cool and efficient, driving speakers easily.

There is a warning caveat though. Class D is not a good idea for electrostatic speakers. But that's another topic.

steve

[steve f]

I stand corrected about how/where to purchase the MMGs. I checked the Magnepan website. They can also be purchased through dealers. Years ago, when I bought a pair, they were mail order only.

steve

[ajmac]

I appreciate Mark's (mcgsxr) reminder of

determine your goals, your budget, your willingness to DIY, what concessions you are willing to put up with, your level of comfort around a kit vs going it alone etc.

My goal is to share the beauty of music with my family. Not just the 'sound' or 'melody', but as much of the recorded performance as possible. Therefore, the system, especially the speakers, need to have wide sweet spot. My ATC are studio monitors, and I've tried many ways to get the 3D sound stage. In fact, I got the best result (in terms of sound stage) from placing them like desktop speakers while siting 1.5 feet away. The other part is bass, not the floor-shaking effect, but the notes that I've missing from the bass instruments.

And since I'm sharing the space with my family, it would be very helpful if the speakers can be put out of the way easily. The ATC is 66 lb each, not including the stand. And to be able to put the speaker toward the wall after listening sessions would be great; therefore, I am curious whether 2 Alpha15 (per side) can equal the benefit of using 1 in H-frame.

I was auditioning a pair of 10" sealed subs when I stumbled on this circle and PureAudioProject. The subs may give me the bass notes but it probably would not easy to get the wide sound stage and sweet spot from the combo. I had a few e-mail exchange with PAP, and since they do not have any user in Vancouver, BC, Canada to do a demo, they offered me a slight discount if I were to demo for them. The discount was not able to off-set our dropping exchange rate. And the cost of their xcover is $600-700 a set. So I think I need to find some alternatives. I like their modular design, the frame kits, etc. But I'd like to keep everything (reasonably good amps, active xcover and speakers) within $3k. I could stretch a little if some good gears come off the used market, but I don't want to eat into my 'man-cave' budget yet.

I don't mind doing some DIY. There are some basic tools (drill press, sander, but mostly for metal work) in the office workshop I can use during off-hour. A colleague of mine have built a pair of Linkwitz Pluto with his own modifications. He also built his own amplifiers and has mic for basic measurement. I can get help when needed.

I've followed Matevana's original Hestia posts but I haven't follow his current build. Can someone point me to his latest?

I listen to all kinds of complex music and almost never experience this effect in any of my current OB rigs.     

[richidoo]

OB has great advantages like no box vibration, no box compression, and good room acoustic interaction so it's great for classical music, as long as you have a low Q system to retain the detail and accuracy. Bass violins, tympanies and huge symphonic bass drums need the detail.

Passive OB speakers use high Q bass drivers to play loud and low without electronic boost. The high Q has less detail and control, so you lose the texture and tonal detail needed for classical music. The lack of detail in the woofer smears the midrange driver it's crossed to. Eminence Alpha, Hawthorne, AE Dipole, etc all have high Q to work in OB speakers without any boost, but they lack detail compared to low Q bass drivers.

You can use an active crossover with bass boosting EQ and a dedicated amp to drive a low Q driver to play loud and low with plenty of detail. You need special hifi bass drivers with tight suspension and high excursion which means low sensitivity and high price, so you need a more powerful amp and active crossover circuit, so it is more complex and expensive. This is how Linkwitz Orion works, with excellent results. This probably offers the best possible performance if you want to spend the money on great sub drivers and know how to build and tune it.

Another alternative is a servo OB sub which uses that high Q driver for easy loud and low extension on moderate power, but it makes up for the sloppy suspension and lack of detail by using a servo controlled feedback loop to electronically lower the Q of the whole system to make the detail you want for classical bass. The servo forces the cone to match the input signal at all times, despite the high Q driver. For classical music in OB I think it's a good way to go. The servo sub system has a servo driver and a servo amp that work together. They make special high Q servo drivers just for OB.
Rich

[ajmac]

Thank you for the explanation, Rich.

Would you have some recommendations in mind? I've the circle for your posts on OB. It seems GR Research offers 12" subs for OB as well as servo amps. Are other combos that'd meet my need?

Thanks in advance.

[matevana]

I've followed Matevana's original Hestia posts but I haven't follow his current build. Can someone point me to his latest?

Hi Ajmac,

I own 2 OB sets currently; the Hestia V and Hestia V Dome (both builds are outlined on A/C). They do not require DSP and use a super easy to construct H frame (ready made cube) along with low Q drivers. The more complex top baffle is available from a shop as a flat pack at a very nominal cost, pre milled on a CNC machine, finished or unfinished. 

I have refined the passive crossover(s) from the original post(s) in an attempt to gain additional detail and final resolution; just haven't had time to update the site with my day job encroaching on hobby-time.

I can say that I am very pleased with both designs; each are unique in their own way.   

[JohnCZ]

Passive OB speakers use high Q bass drivers to play loud and low without electronic boost. The high Q has less detail and control, so you lose the texture and tonal detail needed for classical music. The lack of detail in the woofer smears the midrange driver it's crossed to. Eminence Alpha, Hawthorne, AE Dipole, etc all have high Q to work in OB speakers without any boost, but they lack detail compared to low Q bass drivers.

You can use an active crossover with bass boosting EQ and a dedicated amp to drive a low Q driver to play loud and low with plenty of detail. You need special hifi bass drivers with tight suspension and high excursion which means low sensitivity and high price, so you need a more powerful amp and active crossover circuit, so it is more complex and expensive. This is how Linkwitz Orion works, with excellent results. This probably offers the best possible performance if you want to spend the money on great sub drivers and know how to build and tune it.

Rich
[/quote]

Hey Rich,
A question regarding high Qts vs low Qts on open baffle drivers, mainly bass drivers.
I've been using the Alpha 15 which has a relatively high Qts  of 1.26. In the  process of upgrading my open baffle design with a little more effective bass driver, the Alpha 15. I've had some recommendations like the Delta 15lfa or even the Definimax which have a Qts in the mid 50s. If I use one of the lower Qts drivers and not use EQ, could I get by with bass boost on my plate amp?

The Alpha 15 is ok in my current application (18 in baffle with 12 in wings on the back). The bass is sometimes a little thin and not focused. Right now I am not using a separate amp on the bass. The main amp is driving the mids and bass (with a cap and inductor filter).