515-8G HP ; how low?

[Cobra2]

Shipping from here (export) is more than $ 250 for 2x 515-drivers (by post-system. I admit that I did not check with other transporters, yet). This really ruins sale/export of a heavy item...
I can get hold of a complete ok looking & working 816a (w/515-8G-HP) for less (each)!
(Several, actually!)
A friend tried to make a model-19 clone out of a pair of these 816, (with a "flat" front-plate, they have just a little more volume, that can be reduced by bracing), -but he admitted that he lost some of the "smack" & fun-factor of this bass-arrangement.

Arne K

[bowtie427ss]

FWIW, my days of international transactions are over as a buyer, and i'll only sell internationally if international part of the shipment is done by an "agent" at their sole liability.

It seems we now have a situation where "authorities" at the US border are opening parcels to inspect them, particularly incoming parcels.

These "authorities" are under no obligation or liability to properly repack the parcels, they are not held accountable for their actions.

Long story short, no shipping insurance provider that i'm aware of will award a claim for damages that have occurred as a result of improper packing.

Beware folks, you risk the damage/loss of the goods in addition to being obligated to refund the buyer in full as Paypal almost universally sides with the buyer.

[GM]

Good to know, thanks!

GM

[Earl K]

Hi,

- If I was in a similar situation ( blessed with an over abundance of midbass woofers such as the 515-8HP / but land-locked within Norway & therefore having little to access to "flipping the originals for a more desired bass-woofer" ) I'd be looking to find a way to turn those 515s into a driver that'll produce more bass .

- An idea ( such as this ) is only for the adventerous, & those who have the required tools to measure a woofers TS parameters ( & those who understand the relevance to woofer/enclosure alignments that the new numbers will offer ) .


- One way ( to turn a midbass woofer into a bass woofer ) is to add weight to the cone to increase its' MMS ( moving mass ) up to a value ( more conducive to producing convincing bass ) . My calcs. show that you want to get the 515-HPs "MMS" up to at least 100 grams .
- This is accomplished by adding weight to the cone . I'd start with 20 to 30 grams ( in a unconnected ring of non-ferric/non-magnetic metal ) temporarily glued to the joint between the dustcap & the cone .
- The advantage of adding cone weight in this way ( as opposed to just gooping up the cone with aquaplas ) is that the originals' midbass response is mostly retained .

- This is the very approach that JBL used when they decided to create the 2231/5 from their standard "Sound-Reinforcement" woofer; the 2205 or 2225 .
- They glued a 35 gram, lead-like "mass-ring" to the top of the voice-coil to increase the "MMS" . They kept the originals' paper cone and voice-coils .
- JBL also increased the compliances ( looseness ) of the spider & surround ( which is admittedly hard for the "hobbyist" to do ) .

- FWIW, typically, by not changing-out any of the original compliances ( spider or the surround ) / the Qts will rise some (ie; sacrificing a bit of cone control for better bass reproduction ) . Vas will increase .
- Depending on the resilience of the stock Altec parts, Fs "may/or may" not drop very much ( one would need to monitor the trend as more & more cone weight is added ) .

- Once a reasonable new moving weight is arrived at / it would be best to permanently glue it just over the voice-coil ( but under the dust-cap ) . Obviously removal of the cap & it's reinstallation will be necessary .

- Just a thought, mostly for those "hooped" by geographical ( &/or ) economic circumstances .

>< cheers