High efficiency hi-fi speakers, DIY suggestions?

[Pirium]

After taking a closer look on Klipsch, I'd really like to build my own speakers with efficiency over 95db/1w, but can't find any kits or suggestions... Klipsch is really overpriced here in Norway, RF82 cost 1850 US dollars.. My goal is a speaker not (much) bigger than the rf82, but as loud and with the same hifi-quality. I'm a bit suprised that the web isn't flooded with DIY-kits like that, am I the only one that wants to play loud, without monster amps or monster speakers, or is Klipsch making "unbeatable" speakers? Like the aspect of DIY, and would like to save some money too.

Sorry if the title is misleading or anything, I'm not used to writing in english.

[Anthony]

More people will chime in here, but as far as that efficiency goes, you basically have two choices:

Line array
Prosound drivers

I know there are people who build custom folded horns and some horn kits (Pi audio comes to mind), but those are most popular.

I have a pair of Eminence 10" woofers with a coaxial tweeter that are around 95dB, if I remember right. It was an Adire audio kit a while back, but the parts are still available. I am driving them with 8W tube amps.

I am not as familiar with line arrays, but they seem popular in the DIY community, so maybe someone with more experience there will respond.

Good luck and welcome to the shack!

[WmAx]

Pirium wrote:

After taking a closer look on Klipsch, I'd really like to build my own speakers with efficiency over 95db/1w, but can't find any kits or suggestions...

1st, I think you need to re-examine why you want to build something like the Klipsche. Klipsche units do not measure or behave as a known high fidelity speaker should, according to the current perceptual research in the realm of loudspeaker systems.

If it is simply 'loud and clear' that you want, listen to DS-21. The pro sound drivers will get LOUD with low distortion with low power and you can manage decent fidelity with a very careful design.

You can achieve loud and very high-fidelity together, but this usually requires very high power amplifier and high quality drivers with very linear motor systems.

I guess it comes down which one of these following circumstances fits you best:

Are you one to sit in a dark room concentrating on the music?

If so, I would gravitate towards pointing you to the high-power, conventional speaker system design method.

Are you one to listen to music usually in a casual mood, while doing something else, and you want the ultimate party speaker?

If so, I would gravitate towards pointing you to the high-efficiency pro driver speaker system design method.

BTW, regardless of which method you prefer to choose, I recommend building a known good quality design that is published. It is no simple feat to design/engineer a high fidelity speaker system without a substantial amount of study/research/experimentation.

-Chris

[Pirium]

WmAx wrote:

1st, I think you need to re-examine why you want to build something like the Klipsche. Klipsche units do not measure or behave as a known high fidelity speaker should, according to the current perceptual research in the realm of loudspeaker systems.

If it is simply 'loud and clear' that you want, listen to DS-21. The pro sound drivers will get LOUD with low distortion with low power and you can manage decent fidelity with a very careful design.

You can achieve loud and very high-fidelity together, but this usually requires very high power amplifier and high quality drivers with very linear motor systems.

I guess it comes down which one of these following circumstances fits you best:

Are you one to sit in a dark room concentrating on the music?

If so, I would gravitate towards pointing you to the high-power, conventional speaker system design method.

Are you one to listen to music usually in a casual mood, while doing something else, and you want the ultimate party speaker?

If so, I would gravitate towards pointing you to the high-efficiency pro driver speaker system design method.

BTW, regardless of which method you prefer to choose, I recommend building a known good quality design that is published. It is no simple feat to design/engineer a high fidelity speaker system without a substantial amount of study/research/experimentation.

-Chris

Guess I'm more of a casual mood guy, but my music taste is very wide, I'd like something which would perform good on most types of music. Good being as good or better than ie RF82, which gets very good critics here in Norway.
I got the space for big speakers, got my own HT-room in a while. Could mention that I'm going with separate subs, so the mains don't have to do much below say 35-40hz. Most important is good sound, capable of playing loud with low distortion, drivven by ie Onkyo 875, which is the most likely reciever to be used.

[WmAx]

DS-21 wrote:

While the second point is undoubtedly true, and it makes the bigger stuff look that much better, because it's operating so far under its limits at any non-dangerous SPL.

However, really high power isn't really required. Keep in mind that a 96dB/w/m speaker will have identical SPLmax to a typical 86dB/w/m 7" 2-way bookshelf with 1/10 the power. So if 700W are needed to meet one's SPL needs from the latter, 70 will suffice for the former. And of course, the 96dB/w/m system will be far more linear at those SPL, with less power compression, etc.

I typically target a 90db minimum sensitivity range. The problem is that not many mid band drivers with the most desirable CSD and axial radiation patterns combined will be very high sensetivity. But no worries, modern good quality drivers have far more than sufficient linearity vs. spl to be used for high fidelity situations, when used in an intelligent design.

-Chris

[thxgoon]

DS-21 wrote:

And of course, the 96dB/w/m system will be far more linear at those SPL, with less power compression, etc.

This is the 2nd time I've seen you reference this and I'm curious to how sensitivity relates to compression? (given that sufficient amp power is available) Is it a thermal issue or is there anything else involved?

OP: What was it about the Klipsch's that you like?

[WmAx]

thxgoon wrote:

This is the 2nd time I've seen you reference this and I'm curious to how sensitivity relates to compression? (given that sufficient amp power is available) Is it a thermal issue or is there anything else involved?

OP: What was it about the Klipsch's that you like?

Usually, in regards to high sensitivity drivers, this is a function of lower mass vs. a given radiation area. Assuming you have two drivers with equivalent voice coils and motors, and one has a cone mass of 2x compare to the other, the lower mass cone will be able to have greater movement for a given energy input. Every voice coil is subject to power compression at some point- where the coil heats up and becomes more resistive. Given all other factors equal(for theoretical discussion), the lower mass version in this example will reach a higher SPL before the compression sets in at any given ratio, compared to the higher mass cone variant. With pro sound applications, maximizing SPL vs. power input is critical in importance, due to the huge areas required to be filled with high SPLs. For home use, this is not an issue, as any good quality conventinal drivers of average sensitivity can produce very high SPLs in a regular environment before appreciable compression becomes an issue. At least, that is true with a proper/intelligent design. You will need substantially higher power, though. So you might wonder: why ever use lower sensitivity drivers? Simply put, the above was based on 'all else being equal'. Most often, all else is never equal. Many of the more desirable characteristics for a specific target design/objective may only commonly be found with relatively higher mass designs. Let's take woofer as an example: a pro sound woofer may typically have a substantially higher sensitivity, as compared to a conventional high power subwoofer. The reason is it has a lower mass cone and surround, and is designed primarily for higher frequency ranges(usually 40hz and over) and lower excursion levels, which all adds up to typically higher sensitivity. While this unit may be superb for this upper bandwidth, it would not fair well in the commonly desired applications of HT enthusiasts today that want very high SPL response at 20hz or even lower ranges. This bandwidth requires a higher mass driver with lower FS and far greater excursion capabilities. This is just one example, as applied to LF drivers.

-Chris

[Rodny Alvarez]

You said you want high Sensitivity..................here some drivers




beyma.jpg


605Nd

This 6.5” mid frequency loudspeaker has been designed on the basis of the 6MI90 with the purpose of improving the efficiency. The new one includes a high-energy neodymium magnet that increases it and reduces the loudspeaker net weight. Thus, the 605Nd is 3 dB louder and 30% lighter than the ferrite version. By the other hand, this loudspeaker is mounted with an special cast aluminium basket that reduces mechanical vibrations and increases thermal dissipation. All these improvements combined with the 6MI90 excellences (low harmonic distortion and extended frequency response), result in a superb transducer for sound reinforcement applications.

Key Features

- Exceptional power handling: 125 w AES
- High sensitivity: 100 dB
- 1.5” (38.5 mm) edgewound aluminium ribbon voice coil
- Aluminium basket
- High efficiency: 3.3 %
- Excellent dispersion control due to the use of a phase plug
- Low harmonic distortion
- Linear frequency response


Technical specifications
Nominal diameter 165 mm. 6.5 in
Rated impedance 8 ohms.
Minimum impedance 6.6 ohms.
Power capacity 125 w AES
Program power 250 w
Sensitivity 100 dB 2.82v @ 1m @ 2pi
Frequency range 150-8000 Hz
Voice coil diameter 38.5 mm. 1.5 in
Magnetic assembly weight 1.2 kg. 2.65 lb.
BL Factor 13.15 N/A
Moving mass 0.010 kg.
Voice coil length 7 mm.
Air gap height 6 mm.

beyma1.jpg

CP22

This compression tweeter is designed for use in multi-element loudspeaker systems in sound reinforcement applications that require high output, narrow controlled dispersion and long throw. This model produces a very high output level with flat response and excellent transient attack. This unit features an aluminium voice coil diaphragm assembly, which is field replaceable without soldering.

Key Features
- 1.5” (37.6 mm) edgewound aluminium ribbon voice coil
- Great power handling: 25 w AES
- Aluminium diaphragm
- Precise directivity: 40º conical
- High sensitivity : 107 dB
- Compression tweeter designed for long-throw high frequency applications.

Technical Specifications
Rated impedance 8 ohms.
Minimum impedance 8.5 ohms.@ 9 kHz
D.C. Resistance 6.1 ohms.
Power capacity 25 w AES
Program Power 50 w
Sensitivity 107 dB 1w @ 1m
Frequency range 4 - 20 kHz
Recommended crossover 5 kHz or higher
Dispersion H x V 40° conical
Voice coil diameter 37.6 mm. 1.5 in.
Magnetic assembly weight 1.2 kg. 2.64 Ib.
Flux density 1.55 T
BL Factor 5.2 N/A


I think they have some crossovers


http://profesional.beyma.com/ENGLISH/producto.php

[thxgoon]

DS-21 wrote:

Completely, utterly wrong. Take some measurements before and after playing a 94dB pink noise signal on a typical domestic speaker for an hour. It'll open your eyes.

Does it really take an hour? If so this issue seems relatively moot. Voice coils are relatively light and are made of conductive metal (ie conductive to heat) so it shouldn't take more than a few seconds for it to heat up with a given input power.

Do you have any further info, preferably graphs and numbers, that would show just how much compression sets in at a given temp? I've had my system (last night as a matter of fact, watching concert dvd's with the roomies I actually managed to put my amp in thermal protection, whoops!) loud for hours on end and the only thing I noticed different about the sound had more to do with my ears getting tired than my speakers getting tired.

Hey I realized in my little story telling a benefit to the OP of a higher efficiency design... the amp works less hard and you don't have as much chance of sending it into protection and you can party for longer! Ha! I knew I could keep this on topic

[Pirium]

thxgoon wrote:

OP: What was it about the Klipsch's that you like?

I like that they can play LOUD from "small" speakers, and still be good music-performers. I like the dynamic range, the "drive" they put in to music, to put it simple, i like the sound they make.

I also like the idea of playing at reference level without stressing the amp.

My use is mostly HT, but I play a lot of music too, and since I soon got my own HT-room, I'd like to be able to play loud without "destroying" the sound.

[Pirium]

Rodny Alvarez wrote:

You said you want high Sensitivity..................here some drivers




Attachment 5947


605Nd


Technical specifications
Nominal diameter 165 mm. 6.5 in
Rated impedance 8 ohms.
Minimum impedance 6.6 ohms.
Power capacity 125 w AES
Program power 250 w
Sensitivity 100 dB 2.82v @ 1m @ 2pi
Frequency range 150-8000 Hz
Voice coil diameter 38.5 mm. 1.5 in
Magnetic assembly weight 1.2 kg. 2.65 lb.
BL Factor 13.15 N/A
Moving mass 0.010 kg.
Voice coil length 7 mm.
Air gap height 6 mm.

Attachment 5948

CP22


Technical Specifications
Rated impedance 8 ohms.
Minimum impedance 8.5 ohms.@ 9 kHz
D.C. Resistance 6.1 ohms.
Power capacity 25 w AES
Program Power 50 w
Sensitivity 107 dB 1w @ 1m
Frequency range 4 - 20 kHz
Recommended crossover 5 kHz or higher
Dispersion H x V 40° conical
Voice coil diameter 37.6 mm. 1.5 in.
Magnetic assembly weight 1.2 kg. 2.64 Ib.
Flux density 1.55 T
BL Factor 5.2 N/A

Nice drivers, just need som woofers to go with that. Would like a bit more excursion on the mid, though..

[justin.kerr]

I have Klipsch Rf 83's, and I don't think it would be very hard to build speakers that would match them for output/sound quality.
I am also looking for a 5.0 set up. With high sensitivy, and high power handling, coupled with great sound. What I am looking for is around 102db-106db for sensitivity, and around 4,000 watts continous power handling per speaker. But it looks like the cost of just the drivers will be around $3,000. per speaker...

[WmAx]

DS-21 wrote:

Completely, utterly wrong. Take some measurements before and after playing a 94dB pink noise signal on a typical domestic speaker for an hour. It'll open your eyes.



Which will only lead to more power compression.

1. A constant high power signal such as pink noise is not an exact representation of the power use in music, since music is not constant. If you wanted precise values in a specific situation, you could actually use actual music and record a song, and then re-record it at another SPL level, and examine the precise compresssion differences in the peak sections of the signals after synching them later in software.

2. 94dB is a very high average SPL for music playback. Yet, playing music at this average level with 90dB range average drivers with good quality motors will result in marginal compression at best. Barely noticed on a measurement.

Let's assume we take a single channel of an average sensivity 89-90dB speaker system measured, 6.5" driver and dome tweeter with decent motors, using this set down to about 80Hz(assuming active crossovers are switching over to subs by this point). With an averaged sweep at say 96db at 1 meter, vs. an averaged sweep at 101dB(4x power) at 1 meter, one could expect less than a dB of compression difference between the two in the lower band(<200Hz), and far less than 1/2 of a dB at in the higher band(>200Hz), with averageed distortion at inaudible levels for music playback. A sweep will probably be more representative of the kind of power to be expected in music, and still, likely more demanding, depending on the time of the sweep.

This is not any level of compression that is substantial.

The above scenario assumes averages of real measured devices in the conditions as outlined. The above scenario would be representative of extremely high music listening levels - ear damaging levels.

-Chris

[justin.kerr]

Depending on room size, and listening position, that scenario could deliver 85db to the listener, that is not extreme, ear damaging levels.

[WmAx]

justin.kerr wrote:

Depending on room size, and listening position, that scenario could deliver 85db to the listener, that is not extreme, ear damaging levels.

That is one speaker, measured in anechoic conditions. You add 3-4dB roughly, to account for a second unit. Then you account for room/boundary reflections reducing distance losses. In an average room, the final output of 2 speakers, at an average listening distance of 2 meters would be in roughly in the same general SPL vs. power range as the 1 meter measurement of a single speaker, minus 2-3dB on average. The upper SPL example given above would still result in nearly 100dB, given all of these conditions. The upper example above demonstrating compression difference uses sine wave sweeps that heat up the VC, not quick transient signals which do not. Transients peaking at 110dB for short durations would not cause much additional thermal compression, as the transients are too short in duration to heat the VC by a further substantial degree.

I have yet to come across a properly designed/implemented system of average sensitivity(90dB 1 watt/1meter average) with good driver motors that had what could be considered an audible problem due to compression for commercial music playback in regular room conditions when used with the appropriate subwoofer system and crossover. But by the way the DS21 poster is wording his posts, one could erronously assume that this was the case.

-Chris

[justin.kerr]

Thats a very close listening position.
Also OSHA ratings are established A-weighted. There are not many speakers capable of 105 db at 20 hz, A-weighted.
For 1 hour, continuous 105 db is safe.
Short "blasts" up to 140 db safe, according to U.S. Military Standard 1474D.

[thxgoon]

Ok guys (and/or gals) I think we're splitting hairs and getting a bit far off topic.

Pirium, I understand why you like the Klipsch sound as I've never heard anything else quite like them. Unfortunately I do not have much experience in the DIY world for speakers so I can't comment much on building something like them. Line arrays have the added benefit of dramatically higher efficiency and higher power handling... this might be a solution???

[WmAx]

justin.kerr wrote:

That a very close listening position.
Also OSHA ratings are established A-weighted. There are not many speakers capable of 105 db at 20 hz, A-weighted. For 1 hour continuous 105 db is safe. Short "blasts" up to 140 db safe, according to U.S. Military Standard 1474D.

I was not trying to specifically establish hearing safety limits. I was trying o relate to the substantial level that such a SPL equates to in full range use. At about 3 meters (9-10') distance (which I consider a very average for average situations when listening critically), only a dB or 2 of additional loss would occur in a regular room. But as a side issue concerning safety, how long does one listen to music? That's needs to be decided. At 96-99dB, which is extremely loud, and a figure which a high quality average sensitivity speaker set can manage with no substantial compression problems, given a sufficient power amplifier, 4-5 hours is the maximum limit of safety, accumulated in a 24 hour period. Now, if someone actually intends to play music over 100dB averaged on a regular basis, I would in fact recommend that they use high efficiency drivers, or a line array of regular drivers. Sound quality is probably not the highest priority anyways, assuming this condition. Let's put this into perspective: the average classical music performance has an average SPL well below 90dB. Only peaks are over 100dB, and transient peaks do not cause substantial compression. I would speculate that most people, when they are in a mood for short term 'rocking out' at high SPL, do not exceed an averaged energy SPL resulting in greater than 100dB at the listening position, unless they have pre-existing substantial hearing damage.

-Chris

[justin.kerr]

I have found that loudness is completely subjective. To one 150db is loud, to another 80db is loud. When I am "rocking out" lol, the db meter averages around 125-130, and I am looking to upgrade. lol

[WmAx]

justin.kerr wrote:

I have found that loudness is completely subjective. To one 150db is loud, to another 80db is loud. When I am "rocking out" lol, the db meter averages around 125-130, and I am looking to upgrade. lol

Exactly what does this refer to? The mid/treble band? Or a power car subwoofer system run at much higher SPL level compared to the mid/treble band?

125-130 dB in bass is easily tolerable. 125-130dB range in mid/treble band can rapidly cause hearing damage and I would speculate is probably considered extremely painful by most people with regular hearing after a short period.

Virtually no home system can run averaged SPLs in that range, in the mid-treble bands. In order to do this practically, one may as well install pro-sound re-enforcement speaker systems in their house using high powered compression drivers and large high efficiency woofer mid-bass systems, along with an array of horn subs against the wall. Dare to use it at those SPLs on a regular basis and one can expect to find themselves with severe tinnitus eventually, and severely deficient HF hearing.

-Chris