Best money no object 18" driver?

[gavman]

hello all,

i've been trying to avoid asking this question for a while, but i really can't put it off any longer as it's time to order some speakers.

i've built a high-end domestic hifi and absolutely do not want to scrimp on the drivers.
i really like the look of the Aurasound 18's, particularly after what's been said about them on here by cult members, however they do seem to be very inefficient?

are they the current 'state of the art' in terms of sound quality?

if not, may i ask which are?

my room is ~3500 sq ft and i plan to use four of the 18's in a manifold with a 9 sq ft opening into the listening room, and the ceiling has been strengthened with additional steel beams to take the weight of the Aurasound units.

many thanks for your time and opinions

[carvernut]

yes compaired to other hifi speakers they do seem low efficiency but... with the displacement of 4 18 drivers and the combined gain from mulitple drivers and the manifold design which acts somewhat like a horn chamber you don't need alot of power to reach unbarable levels, 800va is more than i need to hit well over 130dB's with 8 AEIB15's and they have similar sensitivity as the Aura18's

you are talking about the NS18-992-4A 18's from Aura correct?
If you have the money those are VERY nice speakers.

can you give us a layout of your room and how you have your speakers positioned please?

Here are the manufacturer's T/S Parameters for the AE IB15.
Fs: 16Hz
Qms: 6.8
Vas: 439L
Cms: .45mm/N
Mms: 220g
Rms: 3.239
Xmax: 18.5mm
Xmech: 25mm
Sd: 830sqcm
Vd: 3.07L (p-p)
Qes: .78
Re: 5.5ohm
Le: .33mH
Bl: 12.49
Pe: 500W
Qts: .7
1WSPL: 86dB
2.83V: 87.3dB


and the Aura NS18

Nominal Diameter . . . . . . . . . . . . . . .18 inches (477 mm)
Nominal Impedance (Z) . . . . . . . . . . 4 Ohms
Sensitivity, 1W/1m (E) . . . . . . . . . . . 86 dB @ 100 Hz
Power Capacity, RMS (Pe) . . . . . . . . 800 W
Power Capacity, Peak . . . . . . . . . . . 3200 W
Frequency Range (-10dB) . . . . . . . . Fo - 1.5 kHz
Minimum Impedance . . . . . . . . . . . . 5 ohms
Voice Coil Diameter . . . . . . . . . . . . . 99.2 mm
Voice Coil Winding Length (h) . . . . . 25.4 mm
Voice Coil Number of Layers (n) . . . . 1
Voice Coil Former Material . . . . . . . . Glass composite
Voice Coil Wire Composition . . . . . . Aluminum Ribbon
Magnetic Material . . . . . . . . . . . . . . Neodymium radial
Stray Flux Shielding . . . . . . . . . . . . . Inherent
Magnetic Gap Depth (He) . . . . . . . . 50.8 mm
Cone Material . . . . . . . . . . . . . . . . . Aluminum
Surround Material . . . . . . . . . . . . . . Injecton molded rubber
Polarity, Outward Motion . . . . . . . . . Positive voltage on (+) terminal
Net Weight . . . . . . . . . . . . . . . . . . . . 19.7 kg
Thiele / Small Parameters
Resonant Frequency (Fo) - Fs . . . . . 20 Hertz
Voice Coil DC Resistance - Re . . . . . 3.1 ohms
Total Q - Qts . . . . . . . . . . . . . . . . . . 0.47
Mechanical Q - Qms . . . . . . . . . . . . 7.7
Electrical Q - Qes . . . . . . . . . . . . . . 0.50
Equivalent Volume of Air - Vas . . . . . 322 L
Radiating Piston Area - Sd . . . . . . . . 1164 cm 2
Electrical / Mechanical Parameters
Flux Density x Length - BL . . . . . . . . 17 Tesla-meters
Compliance - Cms . . . . . . . . . . . . . . 170 ìm/N
Total Mass - Mms . . . . . . . . . . . . . . 400 grams

[ThomasW]

You've been posting about this since mid Nov 2006. In Feb 07 you said you'd post a floor plan "in about a week".

At this point in time we know nothing about this installation other than there's a "9 sq ft hole" located somewhere in the ceiling of a "3500 sq ft room" (a single room larger than most entire homes)

So some 18 months into the discussion the basics haven't been posted. Lacking specifics regarding the installation makes further discussion pointless.

[gavman]

i offered to e-mail the plans to you, and i repeat that offer now

i can't even view them myself, let alone host them

apologies for my IT incompetence, but i'd pretty much concluded you didn't want to help me.

however i hoped it wouldn't preclude me from asking a generic question about drivers to the members. i was still going on your recomendation but wanted some confirmation/clarification

have you ever had a large building project Thomas?

these things can so easily get away from you, i should've moved in this month but still the house isn't ready.

since we seem to have rubbed each other the wrong way i've stopped posting and just tried to figure things out myself, however i was hoping to ask about drivers without getting jumped on

the question is straightforward, i'm sorry to demonstrate my ignorance by asking it, but surely a good driver is a good driver, regardless of room size?

i'm simply asking which is the best 18" driver currently available

if i could just draw my plan on the computer screen that would solve all my issues, but unfortunately i am unable

[ThomasW]

The reason you were "jumped on" is a function of the lack of information posted since you started asking questions. Even lacking the plans themselves, it should be possible to provide the basic information used to design an IB. For example...

Where is the IB located in the room?
How far is the listening position from the IB
What are the expected output levels?

If the listening room is really ~3500 sq ft (an area large enough to seat 200 people) 4-18"s are completely inadequate to the task.

Now to answer your questions....

have you ever had a large building project Thomas?

I suppose that depends on whether or not you consider this skylight system...



Or 3.3 million gallon storage tanks



to be large construction projects....

but surely a good driver is a good driver, regardless of room size?

Yes a good driver is a good driver. Whether any specific 'good' driver is the 'best' choice for a particular installation is a completely different question. And yes there are certainly instances where 18" drivers may not be the best choice

i'm simply asking which is the best 18" driver currently available

Probably this one.... www.audiopulse.com/products/subwoofer-drivers/lms-ultra

Whether it's the right driver for your installation is a completely different question.

my email addy is [e-mail]

Or you could upload them to Flickr
www.flickr.com/

[gavman]

thankyou for your answers

heading up north today to check on things, so just spoke to the builder/surveyor. he will send me the latest plans when he returns home this evening, and i'll post/forward them when i return on saturday

the volume of the listening room is 120 cu metres, so my estimates were some way out

the main speakers are at one end, with the hole for the IB exactly between where the mains will stand, and slightly forward to allow for the height difference relative to the listening position, (approx 1.5 metres from the rear wall.)

it will be the same distance from the listening position as the main speakers, ~4 metres

i've never measured my speakers output so i would only be guessing the required IB output, but i will say that i 'like to recreate the live experience'
which is a hifi euphemism for 'loud'
sorry to be so vague

hopefully there's a bit more info there now?

[jasonshep]

HI Gavman,
Take a look at the SICKO 18" Kevin Haskins is designing at diy cable,he is aiming for it to be the best 18" & its looking awesome:'(

[ThomasW]

jasonshep said:

HI Gavman,
Take a look at the SICKO 18" Kevin Haskins is designing at diy cable,he is aiming for it to be the best 18" & its looking awesome:'(

Yep a very interesting design.....

www.audiocircle.com/circles/index.php?topic=50871.20

[gavman]

just had confirmation from the surveyor, room volume is 3985.86 cu ft

[gavman]

cheers jason

i see you're in the uk, do you have an IB yourself?




Thomas you have e-mail

kind regards
gavin

[ThomasW]

We need to know

The height of the ceiling?
The distance from the IB outlet to the listening position?
The desired output level at the listening position?
The dimensions of the room?

[jasonshep]

Gavman,
I do have an ib,did all my research on this site & imported the drivers from the usa, now have stunning bass

[gavman]

may i ask which drivers you used?

Thomas, was my e-mail no good?
i've just made an urgent request to my surveyor to send me another plan of the listening room

[jasonshep]

I used the AEIB15"s,extraordinary value & i just ordered another four

[ThomasW]

gavman said:

may i ask which drivers you used?

Thomas, was my e-mail no good?

I received no email, there are no filters in that particular account

[gavman]

and now?

[ThomasW]

gavman said:

and now?

And now you look for different drivers since neither the Aura 18" or the Audio Pulse 18" are available.

BTW viewing the pdf's at this late date is somewhat problematic we weren't involved in the IB design or location process.

As per the FAQ we don't recommend making the manifold out of a single layer of MDF..

The size of the manifold 72"X 24"X 15.75" manifold is a bit weird (larger than necessary). 72" is a lot longer than needed for 4-18"s.

The engineering drawings provide no specific information about the actual layout of the listening area. Most builders provide floor plans with the layout of the furniture, seating positions, speaker locations, etc, etc.

[gavman]

you basically told me to go away until i was ready to order drive units, hence my lack of contact?

however now i really need to select some drivers as i need to know their combined weight for structural calculations

Thomas, i'm more than happy for you to post my plans on this thread, if possible. then everyone (including me) can see what we're talking about!

i have no intention of building the manifold from a single thickness of mdf, having read the faq's the proposed design was a sandwhich of mdf and marine-type plywood. not sure where you're getting this from- perhaps there's an error on the drawing?

currently the hole in the ceiling is larger than the proposed manifold to allow for some movement of the box before it is mounted permanantly.
this is to allow for:

1 not owning a spare sub to audition proposed locations

2 i won't know the exact location of my main speakers until i move in and position them by ear. this will dictate the starting place for auditions of the IB manifold
(same distance from listening position as main speakers),
which i will then move around within the vacant area to get the best in-room sound.

once i've arrived at the best compromise the box will be fixed in place, until then it will sit on top of the joists for ease of movement

the proposed size of the hole/manifold opening is the combined sd of the drivers, as per the faq's.
so for the four 18's i was proposing a 9sq ft opening into the listening room.
if i'm going to need more drivers then this will increase.

the ceiling height is approx seven feet
the listening position will be exactly between the two mains, approx 4-5 metres from the baseline connecting the mains.
desired output would be equivalent to a nightclub or live event, so quite loud.
the main speakers are very happy at these sort of levels, but also capable of subtlety, which is why i don't plan to scrimp on the quality of the drivers.

i'm sorry there's no furniture marked on the plan but i am basically building the house around the stereo, so there will be no compromise; the listening position will be in the optimum place for sound quality, so at the head of a triangle, with the main speakers forming the baseline.
all other furniture will have to 'fit in' around these considerations, and nothing will be allowed to interfere with the perfect hifi positioning.
there will be a 'dual aspect', with most of the room orientated towards the hifi, however i plan to have another seating position 'back to back' with this, facing out of the main patio windows to the south. tv will be watched from here, the tv going between kitchen and patio windows on the south east corner.

there will be an emphasis on soft furnishings, rather than hard surfaces, with a thick underlay and wool twist type carpet

the void between the rear wall and plasterboard/studwork will be filled with expanding foam to prevent resonance

the floor is concrete with underfloor heating, however it will have a single layer of mdf laid flat between concrete and carpet underlay to reduce sonic refractions and 'improve' their characteristics
all first and second fix carpentry, damproofing and internal restructuring has been done in such a way to prevent any sympathetic resonances/vibrations taking hold, and there is additional steel bracing x 2 gone into the ceiling to allow for the extra mass of the manifold and drivers
both audio systems have their own dedicated 'clean' mains spur, with another for the house and a third, 'dirty' spur for the ground source heat pump, air con, fridge, washing machine etc

many thanks for your time and consideration
gavin

[gavman]

jasonshep said:

HI Gavman,
Take a look at the SICKO 18" Kevin Haskins is designing at diy cable,he is aiming for it to be the best 18" & its looking awesome:'(

thankyou very much, that does look pretty cool....but the site wouldn't let me register to ask for an update or log my interest

[ThomasW]

Unfortunately these won't work as hyperlinks.....

home.comcast.net/~infinitelybaffled/Speaker%20Manifold%20Calcs%20-1.pdf
home.comcast.net/~infinitelybaffled/SPEAKER%20MANIFOLD(DRAWING)-1.pdf
home.comcast.net/~infinitelybaffled/FLOORPLANS%20(Speakers)-1.pdf
home.comcast.net/~infinitelybaffled/FLOORPLANS%20(Speakers)-2.pdf

It will be necessary to copy an paste the URLs since whoever named these files doesn't understand the conventions used to correctly name files.

gavman said:

however now i really need to select some drivers as i need to know their combined weight for structural calculations

Thomas, i'm more than happy for you to post my plans on this thread, if possible. then everyone (including me) can see what we're talking about!

i have no intention of building the manifold from a single thickness of mdf, having read the faq's the proposed design was a sandwhich of mdf and marine-type plywood. not sure where you're getting this from- perhaps there's an error on the drawing?

currently the hole in the ceiling is larger than the proposed manifold to allow for some movement of the box before it is mounted permanantly.
this is to allow for:

1 not owning a spare sub to audition proposed locations

2 i won't know the exact location of my main speakers until i move in and position them by ear. this will dictate the starting place for auditions of the IB manifold
(same distance from listening position as main speakers),
which i will then move around within the vacant area to get the best in-room sound.

once i've arrived at the best compromise the box will be fixed in place, until then it will sit on top of the joists for ease of movement

the proposed size of the hole/manifold opening is the combined sd of the drivers, as per the faq's.
so for the four 18's i was proposing a 9sq ft opening into the listening room.
if i'm going to need more drivers then this will increase.

the ceiling height is approx seven feet
the listening position will be exactly between the two mains, approx 4-5 metres from the baseline connecting the mains.
desired output would be equivalent to a nightclub or live event, so quite loud.
the main speakers are very happy at these sort of levels, but also capable of subtlety, which is why i don't plan to scrimp on the quality of the drivers.

i'm sorry there's no furniture marked on the plan but i am basically building the house around the stereo, so there will be no compromise; the listening position will be in the optimum place for sound quality, so at the head of a triangle, with the main speakers forming the baseline.
all other furniture will have to 'fit in' around these considerations, and nothing will be allowed to interfere with the perfect hifi positioning.
there will be a 'dual aspect', with most of the room orientated towards the hifi, however i plan to have another seating position 'back to back' with this, facing out of the main patio windows to the south. tv will be watched from here, the tv going between kitchen and patio windows on the south east corner.

there will be an emphasis on soft furnishings, rather than hard surfaces, with a thick underlay and wool twist type carpet

the void between the rear wall and plasterboard/studwork will be filled with expanding foam to prevent resonance

the floor is concrete with underfloor heating, however it will have a single layer of mdf laid flat between concrete and carpet underlay to reduce sonic refractions and 'improve' their characteristics
all first and second fix carpentry, damproofing and internal restructuring has been done in such a way to prevent any sympathetic resonances/vibrations taking hold, and there is additional steel bracing x 2 gone into the ceiling to allow for the extra mass of the manifold and drivers
both audio systems have their own dedicated 'clean' mains spur, with another for the house and a third, 'dirty' spur for the ground source heat pump, air con, fridge, washing machine etc

That's a lot of information but doesn't answer the primary questions.

Approximately where will the mains be placed in relation to the IB?

When you're sitting in a chair listening to the stereo, you're sitting where in the room? And what wall are you facing?