Thanks to 90 minutes with the very helpful folks at Prestige Audio in Middlesex and 5 solid days of on-line review searching, I've narrowed down my Roadster install to the following:

Speakers: Diamond Audio HEX 6.5" components or possibly Xine Audios (has anyone heard these? They are comparable to the Diamond Audio M5's but slightly brighter), to be installed in kickpanels. I haven't actually heard the HEX's yet, but I'll do so next week. The reason I've pretty much decided on them without even hearing them is I heard the M5's in a BMW and they rocked. The owner of the car said the HEX's were even better, and yes, worth the extra £200. Once you've heard them, you can't go back, etc.

Amp: McIntosh MC420M or MC440M (haven't decided yet - 4 channels or 6). I'd like to power the components with a channel each, so a sixer would allow that plus save 2 for the subs.

Sub(s): Possibly Diamond Audio 8" M3's, although I've heard that the a/d/s 8"er is good. I'm going to see how things sound without for a while, and then probably take the car into Prestige for a custom sub install somewhere behind the seats. They do nice work.

Incidentally, does anyone know a good on-line dealer for the McIntosh's? My dealer can't get a demo amp, so if I'm going to buy one without hearing one, I may as well get one on-line from the US cheaper. Failing that, does anyone know a UK dealer with McIntosh's on demo?

Let me know what you think!

Sally

Speakers: Diamond Audio HEX 6.5" components

Almost everything I have heard about Diamond Audio speakers has been very good. The only bad thing I have heard probably won't apply to your installation: In very cold weather (say 20 degrees below zero Fahrenheit and colder) the wires embedded in the speaker cones (sending signal to the tweeter part of a coaxial model) are known to fail.

Sub(s): Possibly Diamond Audio 8" M3's,

If there is any way you can go with 10" speakers rather than 8", you will be very glad that you did. You will probably gain close to an octave lower of usable frequency response, but still retain warmth and tonality that you would lose by going to 12" or larger.

Alternatively, you can put two 8" speakers in a common (sealed) enclosure. I have been told (and am building my new system to incorporate this) that the lowest frequency response will be proportional to the total cone area within the enclosure, so that a pair of 8" speakers (96 square inches) would produce the same low end response as a single subwoofer 11" in diameter, yet retain the tonality and responsiveness of the smaller speakers. One caveat: you can only send monaural signal to the two subs. If each sub is playing a different signal, you will have phase cancellation problems.

I haven't actually seen or heard this in operation, but to me it sounds suspiciously like a free lunch! But I'll be finding out in the next few weeks.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"

Final purchases:


- McIntosh MCC446

- Diamond Audio HEX 5.5 components (silk tweeters)

- Diamond Audio HEX Mac Daddy 12" subs


I might end up only using one sub, but I got them cheap and could only buy them in a pair.

I'll let you know how it sounds! : )

Edited by crewe on 06/02/01 09:51 PM.

Ooooh - sounds nice. Pictures if poss!

Paul.

Paul Haigh, Reg. 4120
(mk1) 6GB, Blue, 00254
(mk2) 12GB, Red, 00357

I've just taken delivery of a couple of 12" HEX Mac Daddy subs (they came as a pair and were cheap so I bought them on impulse). Anyone got any opinions on whether or not I should install them or sell them and get 10" versions? Also, how about the debate of one sub or 2? My car is an MGB roadster. I think the 12's will fit, but it's more a case sound - will it be too much? I don't want boomy bass.

Thanks!

The way to prevent boomy bass is to run those subs in sealed enclosures with the proper amount of amplification, and the proper crossover frequencies. And not turning them up too loud.

The Empeg's parametric equalizer (combined with a good ear and some patience) can also help adjust the bass frequencies to reduce boominess.

___________
Tony Fabris

It's not boomy yet - well, I don't know as I haven't installed them. Do you think they will be? I had read stuff about 10"'s sounding tighter, but I thought perhaps since these were HEX's and so renowned for SQ I might be ok. And I'd also heard that bass is the first thing to leave out the open top of the car at speed and that it's a good idea to compensate.... but am I compensating too much?

I had read stuff about 10"'s sounding tighter,

That was probably Doug talking. He could be right, I've never installed 12's in any of my cars. I'm guessing that if you do things right, you can get great sound out of either 12's or 10's. You just have to be careful to get your box volume right and to provide them with enough power.

Do you know if those subs were designed to go in a sealed enclosure or a ported enclosure, or either?

And I'd also heard that bass is the first thing to leave out the open top of the car at speed and that it's a good idea to compensate.... but am I compensating too much?

As long as you can adjust the gain on the sub's amplifier, there's nothing wrong with going "big". Having extra power in reserve is a good thing.

___________
Tony Fabris

As long as you can adjust the gain on the sub's amplifier, there's nothing wrong with going "big".

Well.... maybe. Disclaimer: The following is based only on my own personal experience, not on any research or information from people who know more about car stereo than I do (about 90% of all the people on the planet, I would guess...)

I have found 10" subwoofers to be more responsive and less atonal than 12" (or larger) subwoofers. Now, that may be because I run my single 10" sub full range, and as a result produce quite a lot of mid-range sound (100--500Hz) from my sub. The 12" subs I have heard seem to be dark and atonal, that is non-melodic. Just "blump blump blump" sounding. Even if those "blumps" are crisp and tight sounding, the fullness, richness of sound isn't there.

However, since my car has been called "...a freak of acoustics" by my stereo installer, I can't recommend that you run your subs full-range (i.e., not crossed over). According to most knowledgeable people, my system should sound terrible the way I run it. (It doesn't -- I have the trophies to prove it! :-) But if I ran my sub crossed at 90 Hz, maybe I would think it was atonal just like the 12's I have heard.

The downside of a 10" sub is that it it won't play as low a frequency as a 12". I'd guess the 12s will go about half an octave lower than the 10s. However, there is a clever workaround for this that, even as I write this, my stereo installer is working on for my new car. The lowest frequency that a speaker system will produce is not a function of the diameter of the speakers; it is a function of the total cone area within a single enclosure. So a pair of 10" subs in a common sealed enclosure has the same amount of cone area (157 square inches) as a single 14" subwoofer (154 square inches) and will produce the same low frequencies as the larger sub. It has the further advantage of being able to produce the higher frequencies and brigher sound of the 10" that a 14" couldn't produce. (Not that there is any such thing as a 14" subwoofer, but you know what I mean. :-)

Finally, I'm not sure I would put a pair of 12" speakers in an MGB, just on the off chance that I might want to save room in the trunk for a bag of groceries or a pair of hiking boots or something. A pair of 10s could be packaged in about half the volume of 12s.

Having extra power in reserve is a good thing.

By "power", Tony is referring to the amount of sound producing capacity you would have with the subs, not the amount of watts from the amplifier. Both are good things to have more of than you need, because remember just because you have it doesn't mean you have to use it. It's really easy to turn the gain down on the subs if there's too much. It's real hard to turn it up if there isn't the capacity to have enough.

So, at the end of this rambling discourse... if it were me, I would go with two 10's in a common sealed enclosure with plenty of "headroom" in the amplifier to drive them. I'd try them both crossed over, and full range to see which I liked better.

Be sure to tell us what you did and how it worked out.

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"

Generally you could say:
The greater diameter, the better the low frequencies. So a 12" will be better in giving lowest frequencies than a 10".
Of course a low-quality (!Attention! - I don't say cheap at this point!) 12" could be worse than a high quality 10".
But I think the difference is not that big.

I'm with tony that a sealed box is fine an you don't have a too boooommbastic bass. A sealed box brings a very clear sound and doesn't need a too big box volume.
Every sub can go in either sealed box, bassreflex box or bandpass-box.


TeeMcBee
Got my Mk2! # 080000143

What kind of car do you drive Crewe?

Calvin

A 1974 3.5 litre V8 MGB Roadster

: D

That's right. I almost forgot. I'm attaching a picture of my subwoofer installation. It's mounted free-air to take advantage of the interesting "feature" in convertibles where the trunk is isolated from the cabin. And it allows me to get great sound without losing the trunk. Ignore the bright sweater in the trunk :-).

Calvin

Hmmm... interesting. : ) That looks like a great solution. However nice the install job, I really don't fancy some kind of custom made MDF/fibre glass box behind the seats, (would spoil the old car look and attract too much thieving attention) so sticking them in the boot would be perfect.
How exactly are they installed? Is there sound deadening, or did you just cut holes in the back panel and stick them through? I'm really interested to know how this could be done.
Thanks

Mounting subs free-air like that will work, but you need to take into account the following:

1) The speakers must be specifically designed for free-air use. You have to check with the manufacturer or the dealer to make sure. If you don't, you can blow the subs, or at least shorten their lifespan significantly.

2) The trunk (oh, sorry, "boot") becomes the enlosure. There must be an airtight seal between the cabin of the car and the trunk. As well as around the edge of the speakers. The front of the speaker cones are inside the car's cabin, the back of the speaker cones are inside the trunk.

3) The trunk itself must close and seal tightly.

___________
Tony Fabris

My trunk seals pretty tightly in fact it's a little difficult to open sometimes. :) And I had so many things thrown in to ensure a complete seal as well. All in all I'm happy with it. I'll be by the Norcal meet. I forgot if you're attending or not, but you can listen then.

Calvin

One of the advantages of a free-air (or infinite baffle) installation like mine is there is no MDF box to be found. The sound is very linear as long as you seel the trunk ("boot"). And it's quite stealthy/clean as well. The way it's done is the back panel of the trunk is removed, and rebuilt in MDF, the MDF is then cut and speakers and installed in them, the edges of the MDF mount is made to create a seal, re-install and voila. :) Nice clean bass in the cabin even with the top down. :-)

I'm using JL Audio IB subwoofers. They're intended for just this purpose.

I'm using a Phoenix Gold amp, and the amp has a remote attenuation knob that's mounted in a secret location I can reach with my hand, so then I can adjust the bass for top up and top down and highway vs street with a little twist. :) :)

The best part is I retain my trunk, I can throw a full suitcase in there now. When I had a 8" bazooka tube, I couldn't fit anything in there except the tube. Plus the tube tended to mush out and create bass that doesn't exist. I've quite happy with the built and quality. I've had a lot of bad experiences with audio installation, (you can check by searching the site ;-) so if i'm happy with the sound on the first go, then that says a lot :-).

Calvin

Right, I knew that you knew those things, I was saying that for Crewe's benefit.

And of course I'll be at the meet. Interested in hearing those subs.

___________
Tony Fabris

I'm stating it for the reader's benefit as well. ;-)

Calvin

OK, I've sold the 12's and am on the lookout for a 10 or two. (Girls love to shop ;)

Has anyone heard anything about Aliante subs? They are supposed to be SQ subs and are very thin, requiring not a lot of installation space (80mm depth). They also make an 8" free-air version which is technically a 'mid-woofer' not a sub, but it might do the job up-front until I get round to my boot install.

Any other sound quality subwoofer suggestions would be welcome too!

Thanks (as ever)
Sally

Alis are great subs. Hugo's got a 10 in his Beetle. They're very definitely not the best choice if all you're looking for is sheer power, but for sound quality, they're one of the best options out there. The 8s are, as you say, not so much a sub, and more of a mid-bass driver, so I think you'd probably be better off with a 10, but with them being so slim, getting one into the passenger's footwell shouldn't be too difficult.

Dominic

Cambridge Car Audio
http://www.cambscaraudio.co.uk