6.5 or shallow 8 for mid-bass

Hi all, I am trying to complete a stealth-upgrade of the ICE in my BMW 1-series and thus I intend to use the stock locations for the front speakers (i.e. DLS IR1 tweeters + MB Quart QM100MX 4" in the doors + woofers underneath front seats) and fibreglass a 20l ported enclosure for a 10" woofer in the rear (Phoenix Gold Octane R10). HU is a Nakamichi CD400 linked to an Alpine H701. Tweeters + Mids are powered by a Genesis Q90X amp, mid-woofers (planned for 70-130 Hz) by a Genesis Stereo 100 and the sub by a bridged Genesis Dual Mono. I have yet not completely decided on the mid-woofers to mount underneath the front seats. They will be able to play in a box of approximately 20 dm3 (liter) and it is possible to fit a speaker with a mounting depth of about 70mm. It is thus possible to select among a few 6.5" woofers, but as the stock location also allows mounting a shallow mount 8" woofer (such as the Earthquake SWS or PL Aliante) I am looking for input on how you think that these will compare. Any input is useful - thanks!

I think it would be a waste to mount any mid bass speaker under a seat. The frequency range you want will be lost under that seat. Upwards of 80 hertz becomes rather directional. It would be in your best interest to either use the door location or fab up some kick panel/pods. There are 6.5" drivers available that will suite your needs if space is an issue. For example Rainbow offers separate mids, particularly the Kick bass series within the lines, but I have experience with the Pro Fi line. The new Seas 6.5" is a superb driver found here By the way, very nice setup thus far. There is no digital out on the Nak so you are running the 701 analog?

dwarren wrote: I think it would be a waste to mount any mid bass speaker under a seat. The frequency range you want will be lost under that seat. Upwards of 80 hertz becomes rather directional. It would be in your best interest to either use the door location or fab up some kick panel/pods. There are 6.5" drivers available that will suite your needs if space is an issue. For example Rainbow offers separate mids, particularly the Kick bass series within the lines, but I have experience with the Pro Fi line. The new Seas 6.5" is a superb driver found here By the way, very nice setup thus far. There is no digital out on the Nak so you are running the 701 analog?

Thanks for the input - I hope the system will sound ok when it is done! I agree that it would be better to mount the woofers somewhere else but underneath the seats, but as the car is brand new I would not like to rebuild the doors at this stage. Using the kick-panels would lead to problems with volume for the drivers (as there is no opening behind) and therefore it feels like it would be worthwhile to try the under-seat monting where I could make a sealed box of up to perhaps 10 liter or use the original mounting to allow the speaker to play in volumes up to 20 litres. I think that I'll try this first and if it sounds crap I'll have to rethink afterwards. The Seas driver looks mice, but I think that I will need to save up a bit before I could get t hem! I do not think that Rainbow are on sale in Sweden.. I have looked a bit on the JL6W0 that some seems to have good experiences with in small, sealed enclosures. The CD400 -> 701 is analogue at present (and I do get some hiss due to this) but if I can find the time there is a guy around that has done a mod of the CD400 to create an optical out and that might be something for the future....

Perhaps you could forgoe the 4's? and run an active two way system up front? I realize you have many options with the h701, but some times keeping it simple sounds better. The 1 series doesn't have a three way system built in? Although we don't have them (1 series) in the US, the 3 series all utilize a three way setup. Good luck in the the under seat setup, but I wouldn't expect too much. Like you mentioned above about air space, most mid bass drivers, although not all, perform better in free air applications (i.e doors). Customizing that deck would be sweet!

The 1 series do have a 3-way system standard like the 3-series (where they also have 4"+tweeters in the doors and a woofer underneath the front seats). The air space underneath the front seats is expanded by an opening to the door sills, which will give the speakers underneath the seats about 15-20 litre of air to work with, and eventhough it is not as large as a door, it is reasonable for most I think? I now have an MB Quart QM160TX 6.5" woofer (open air construction) mounted under the front seats and there is no mid-bass peak, which indicates that it has at least some air to play with... The problem with a 2-way system with larger speakers in the doors is the depth - the total speaker height can be no larger than about 50mm without hitting the window -> the doors would need to be rebuilt significantly to fit e.g. 6.5" woofers...