High Efficiency Speakers

 

Bronze Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 52
Registered: Dec-07
I have an integrated tube amp rated 50WPC triode/80WPC UL, switchable, Class AB1 push-pull, and a high quality source. The time is approacing to get serious about a speaker upgrade, and I want to consider high efficiency speakers for a variety of reasons. Mainly, I want to be able to get detail and decent response across the frequency range at low volumes. Second, it would be nice to be able to have something that works if I were to decide to move to a lower power SET amp down the road. Finally, I have read numerous threads here discussing the concept of the first few watts versus the tendency to require more and more power due to inefficient speaker designs. I guess I am in the camp of fewer watts and more efficient speakers. I have also read several technical articles by amplifier designers that support this approach.

It seems like there are quite a few choices at sensitivities around 89dB-91dB or so. Above that, the choices become fewer and lean more towards horns. I am considering a Lowther 2.8 bass reflex design with the switchable ambiance top firing driver. That said, I have no real basis to evaluate this or to judge how this speaker would differ at 102dB sensitivity than one 10dB lower, other than taking the plunge and sending it back if it doesn't work for me. Hence, this post.

Other than the obvious, it also gets complicated with driver selection. My thoughts there would be to go with the middle of the range with what is recommended for a "medium" room. I think I have that currently based on my crude esimtation, but I could use some direction there as well or a good resource. Room is about 15' x 20' carpeted with drywall over cement block. My reasoning is if I'm in the middle and I'm a bit off, it is probably easier to adjust than if I'm at the wrong extreme. It may also be easier to move their location to another room if they are in the middle of the "live" to "soft" range. That would suggest a DX3 or PM6C driver. Quite a cost difference between those two, with the DX3 being more detailed as I understand it. I am not concerned about big bass, and I think the big port design will be fine for me judging by what I have read. If not, I can add a sub with the amp I have which has a pre-out.

http://www.lowtherspeakers.com/

Anyone have any experience with these or can offer any further insights? I am open to alternatives. These are around $2K/pr.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12342
Registered: May-04
.


How did you decide on the Lowthers? Are you aware of the many reasons not to buy a Lowther?
 

Silver Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 162
Registered: Jul-07
There are a lot of options with single driver full range speakers. There are also some 2-way models with pretty efficient designs. You don't necessarily need a 95+db sensitivity speaker to run set amps....depending on your listening habits. I'm in the market myself and haven't quite decided what I want to do yet.
 

Bronze Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 59
Registered: Dec-07
Chris, thanks. I am in the same boat re: deciding what to do.

Jan, I can probably name a couple of good reasons not to buy the Lowthers. My biggest concern (and this is purely conjecture on my part) is that they are very revealing; that is, every single detail, good or bad, of the source and recording will come through loud and clear. Harsh, tinny sounding stuff will probably be unbearable, but then again why would you listen to it in the first place. I have also heard they are one of the more finicky speakers with respect to room acoustics and positioning, and that the bass is somewhat lacking in some of the designs. Finally, the less detailed single driver designs can get congested with full orchestral passages and not image the individual instruments as well.

As to how I "decided" on them--I don't think I have at this point, but what attracted me to them was the low power to drive them, and their detail and imaging. I don't listen to a lot of rock and full orchestra classical, and when I do it is not at high volume, so the "congestion" issue may not be a big tradeoff for me. You could talk me out of them, and that's fine. You have talked me out of other things in my short while here (directly and through reading your posts), and I have been far better off for it. Quite frankly, I thought you might encourage me to pursue them because I have heard you speak favorably about them in other threads, so I am happy to hear the other side as well.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 12347
Registered: May-04
.

A fair number of people consider the Lowthers to be the Holy Grail of SDFR systems with particular Lowthers garnering more loyalty than other models of Lowther. If you decide on Lowthers, do your homework. Most Lowthers have little bass response beneath 40Hz - if that - and require rather large, complex and expensive enclosures that can, when all is said and done, often leave you wondering what the fuss is all about. It's been decades since I last heard a pair of Lowthers (that weren't displayed to their best advantage) but, at the time, I actually preferred the 16 driver Bozak Concert Grands that were beside them. I have always considered the Lowthers to be praise worthy but not my cup of tea for day to day listening. They are in many respects like buying an engine for a Triumph TR4 when you really wanted your first car. They require extreme care in set up and constant maintenance - most Lowther drivers require the voice coil be cleaned and realigned on a periodic basis. I would encourage you to consider one of the other well designed SDFR units and save the Lowthers for a time when you have already convinced yourself they will be worth the time and expense. System pairing is critical and many Lowther users are in disagreement over which system pieces work well with Lowthers. Most, if not all Lowther drivers in most, if not all enclosures, will require a correction network to tame the Lowther shout and this is another area where Lowther owners disagree.


I do not hear SDFR congestion with my speakers even when the music turns to the complex side of dynamic. I don't listen at levels as loud as some others on the forum. The enclosure will make a large difference in how clean the driver remains in this area. There are too many approaches to single driver systems to recommend any particular one. Some listeners prefer open baffles or dipole arangements of drivers. Some think a whizzer cone can manage well while others sneak a high frequency driver in at the very top octave with the single driver connected directly to the amplifier. You have to make up your mind how you wish to go about dealing with the challenges of SDFR's. Each obviously has its advantages and disadvantages. But I would suggest you try something a bit less esoteric than Lowthers for your first adventure with SDFR's. As to bass response, I use a small powered subwoofer with my system which a cross in at about 35Hz with a 24dB slope and run the SDFR's full range. Personally, I think you're on the right track but stick your toe in the water before you jump into the deep end.


.
 

Bronze Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 64
Registered: Dec-07
Points well taken, Jan.

"They are in many respects like buying an engine for a Triumph TR4 when you really wanted your first car."

LOL. Great analogy. I guess it depends on whether you want to spend your time fussing with gear or enjoying music.

Thanks for the advice.
 

Silver Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 163
Registered: Jul-07
Neil, some other products to consider (if you haven't already)....

http://www.tektondesign.com/

http://www.thehornshoppe.com/index.html

http://www.omegaloudspeakers.com/

http://www.cain-cain.com/audio/

...and there are many others. Myself, I think I'm going with an efficient 2-way design. I'm very interested in the SDFR concept, but I think I'll dive into that via a DIY approach. That way I'll learn way more, and then I can decide whether ultimately it is for me. If it suits me, I can decide then whether I think I can build my own that I can live with, or whether I should buy one from someone who knows what the heck he/she is doing.

I've been building some of my own furniture for a while, so hopefully those skills are transferable into speaker cabinets. From what I've been able to google, there are lots of designs that are really pretty straightforward to build. It actually looks like fun. And there are lots of folks on forums like this that are incredibly helpful.
 

Bronze Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 67
Registered: Dec-07
Chris, thanks. I've seen the Horn Shoppe and the Cain & Cain speakers. The others are new to me.

DIY approach has some appeal. You can also buy the cabinets and mount your own drivers, but any way you do it, you have to have a pretty good idea of where you want to land, and right now I don't. At least with DIY, you're not out nearly as much cash, and as you point out you learn something in the process.

"I've been building some of my own furniture for a while, so hopefully those skills are transferable into speaker cabinets."

IMO, if you can build furniture, you should not have too much trouble building speaker cabinets to plans. I'm more of a framing hammer and 12d nail kind of guy, so I would be challenged. LOL!
 

Silver Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 164
Registered: Jul-07
Neil, I think we're pretty much in the same place. The theory behind single driver speakers makes absolute sense to me, but the few I've been able to listen to (very few) have not been particularly appealing to me. I expect like everything else, success is in the implementation. My thinking is exactly as you stated, if I go the DIY route, I'll be out a lot less if for some reason it doesn't work for me.

I think I have finally decided on the monitors I want to buy in the short term, so I'll do that and maybe in the summer give my hand a try at building a SDFR speaker.
 

Gold Member
Username: Frank_abela

Berkshire UK

Post Number: 2784
Registered: Sep-04
Neil

have you heard your amplifier with a very high 100db/w/m sensitivity design? Do you know if your volume control works particularly well at the limit of its range? A volume control is typically two concentric magnetic tracks. If there is even a slight discrepancy between the tracks at the limit of their travel, you'll lose a channel. If you run a very high sensitivity speaker but want to play at low volume levels, you WILL be near the limit of travel.

50w is more than enough to drive any speaker in the low-mid nineties sensitivity (8 ohm nominal impedance). There are many speakers that would fit this bill, not just SDFR designs such as the Lowthers. Incidentally, if your hearing's not shot, bear in mind that you will get little response from an SDFR above 16khz. People keep telling me that at 43 years of age I can't hear anything above 15khz, but I can always tell when the TV is on thanks to its quite subtle 19khz carrier frequency...

Speakers in the 92 - 95db/w/m range:

Focal Electra 1007 be (sensibly sized standmount)
Audio Note AN-K, AN-J, AN-E (less sensibly sized)
Klipsch (name it)
loads more...

As for SDFR, also have a look at Aurousal which use Ted Jordan's 4" JX92 drive unit and doesn't beam hugely while not sounding papery, or MJ Acoustics Subliminal S1R which uses the same drive unit and transmission line technology to give some bass down to 40hz.

Just some thoughts to bear in mind...

Regards,
Frank.
 

Silver Member
Username: Jazzman71

Phoenix, AZ USA

Post Number: 102
Registered: Dec-07
Hey Frank,

Thanks for the reply. No, I have not heard my amp through anything approaching 100 dB sensitivity speakers. However, the volume control through my phones is very sensitive over the entire range. I can notice a discernable difference between 8:15 and 8:30 on the dial - it is continuously variable, not indexed. However,...

I have backed down a bit on the sensitivity and am now looking at a range more on the order of 90-95 dB.

I'll check into those speakers -- I am a little wary of horn designs, although I know the Klipsch horn designs are well regarded. The SDFRs you list I am not familiar with, so I'll have to look into those as well. Thanks again.
 

Silver Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 172
Registered: Jul-07
Frank's spot on about not necessarily needing to go to high efficiency speakers. You can drive most speakers with a good 50W tube amp, depending on your typical listening volumes. Go the high efficiency route if you think that makes sense for you, but your amp won't drive you there.
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